>^ M K Division of Agricultural Sc e n c e s UNIVERSITY OF CALIFORNIA ' ^ NICHOLAS R. ITTNER H. R. GUILBERT FLOYD D. CARROLL A AGRICULTURAL ENT STATION BULLETIN 745 MPERIAL VALLEY and other irrigated desert areas of California are ideal for cattlemen and dairymen to use in pasture and feedlot opera- tions — except for the summer heat load problem. The heat makes cattle breathe hard. Their body temperatures go up. Milk production goes down, and livestock feed consumption decreases. TO FIND OUT how gains of beef cattle and production of dairy cows can be improved through reducing the summer heat load, the University of California set up a study program at Imperial Valley Field Station, El Centre This bulletin tells the results of that study. V PROPER MANAGEMENT, the right feeds, well-constructed shades, cool water, airy corrals, and an understanding of how different breeds react to heat — these are some of the ways described in this bulletin for maintaining beef and dairy cattle production in irrigated desert areas. \ THE AUTHORS: Nicholas R. Ittner is Specialist in the Experiment Station, Imperial Valley Field Station. H. R. Guilbert, Professor of Animal Husbandry, University of California, Davis (deceased). Floyd D. Carroll is Assistant Professor of Animal Husbandry, Davis. SEPTEMBER, 1954 CONTENTS Why This Study Was Undertaken pages 5 to 7 The new trend — matching livestock to climate • Imperial Valley — ideal except for summer heat • How cattle react to heat and humidity • Cli- matic conditions in desert regions. Dairy Cattle 7 to 1 3 Reaction of Holsteins and Jerseys to heat • Effect of coat color on heat absorption • How temperature affects milk production • Effect of heat on pasture use. Beef Cattle 13 to 33 Crossbreeding tests using Hereford cows • Winter feedlot test com- parisons • Summer feedlot test comparisons • Summer and winter tests on pasture • Alfalfa pasture superior to Alta Fescue • Tropical grasses unsuitable • Summer grazing habits of beef cattle • Measurements — a new yardstick • Slaughter and carcass data show similarity. Management Problems 33 to 35 Cattle need effective shades • Avoid a roughage diet in hot weather. mm t $s$ APR. TO NOV. Average for six years 1946-52 August September October Summers are HOT in the desert area Figs. 1 and 2 (above and below). Daily maximum and minimum temperatures and noon humidity, April to November, in the desert area of southern California. mm APR. TO NOV. 1946 ADAPTATION OF BEEF and DAIRY CATTLE TO the IRRIGATED DESERT NICHOLAS R. ITTNER • H. R. GUILBERT • FLOYD D. CARROLL Why, where, and how the studies described here were undertaken Oince the 15th Century, European cattle have been shipped to many parts of the world. They were accustomed to temperatures averaging 35° Fahrenheit in winter and 65° in summer. In climates similar to Europe's they thrived, but in many others they suffered — for example, in those parts of Africa, Australia, and South, Central and North America where temperatures averaged 75° and higher. For a long time livestock research aimed at improving the environment to suit the animals. In the last 50 years this trend has changed. The aim now is to develop animals suited to hot climates:* the Africanders of South Africa, the Santa Gertrudis of Texas, the Brahmans, and the Brahmans crossed with European cattle in the South and Southwest. Imperial Valley — Ideal Except for Summer Heat Imperial Valley and similar California regions have fed large numbers of cattle and sheep during the winter for many * A few of the experiment station researchers who have contributed basic information on how livestock react to high temperatures are: J. C. Bonsma, South Africa; J. D. Findlay, Hannah Dairy Research Institute, Scotland; A. 0. Rhoad, formerly with the Jeneret Station in Louisiana; W. M. Regan and associates, California Experiment Station, Davis; Samuel Brody and colleagues, University of Missouri; and M. H. Fohrman, U. S. Department of Agri- culture. years. Imperial Valley alone fed some 250,000 head of cattle in 1951 and usu- ally feeds 200,000 sheep yearly. Except for high summer temperatures this re- gion is ideal for pasture and feedlot operations because of its long growing season for alfalfa and other pasture crops, because of its abundance of cheap irrigation water, and because of its low average yearly rainfall which eliminates much of the mud problem. f As more cattlemen began operating in Imperial Valley and other hot California valleys on a year-around basis, the need became apparent for information on summer management of livestock. Early in 1946 the University of California in- augurated a livestock program at Impe- rial Valley Field Station, El Centro, to study the following: best shades for cattle, livestock gains, food consumption and economy of production in summer; and the comparative values of the differ- ent breeds of cattle fed. These studies are still in progress. The winter research program at the station consists primarily of livestock management studies on pasture and in the feedlot, comparing European and t Extension Circular 176, Desert Agriculture, by N. L. McFarlane and G. L. Winright, gives detailed information on crops and pastures grown in these areas. Manual 2, California Beef Production, by H. R. Guilbert and G. H. Hart, has considerable data on the heat tolerance of cattle. 5] Brahman types of cattle. In addition to this program, the station continuously searches for pasture grasses and legumes that are best adapted to irrigated desert areas. How Cattle React To Heat, Humidity Climatic stress in tropical and semi- tropical regions is caused by air temper- ature, solar radiation, and humidity — singly or in combination. There is evi- dence that these factors affect the physio- logical systems of animals through their anterior pituitary, adrenal, and thyroid glands. The air temperature beyond which cattle begin to have a higher than normal body temperature is known as the crit- ical temperature; it may be defined as the highest temperature the animal can stand continuously without increase of body temperature. Normal body temper- ature for the cow is usually considered to be 101° to 102° F.* and the comfort zone for respiration rate is between 20 and 50 per minute. There is some variation among breeds in the critical temperature. Regan (1) found that for full-fed producing cows the upper critical temperature was about 80° for Holsteins, and 85° for Jerseys; and with each 18° increase in air tem- perature, respiration rates approximately doubled. Ragsdale et al. (2) found that the critical high temperature at which the depressing effect on milk production, feed consumption, body weight, and a rise in body temperature became evident was 75° to 80° for Holsteins and 80° to 85° for Jerseys. Brahmans are reported by Kibler (3) to have a critical tempera- ture between 90° and 95°. Reports from South Africa and the United States indicate that Herefords have the highest heat tolerance of the European breeds, followed by the Short- horn and then the Angus. At 90° Here- * All temperatures in this bulletin are on the Fahrenheit scale. fords had a respiration rate of 85 per minute, Angus 95 and Shorthorn 141 — Bonsma (4). Since European breeds do not sweat, air movement may not be im- portant. Humidity apparently is not a great factor in the comfort of the dairy cow, except when it approaches saturation. Regan (1), and Seath and Miller (5) be- lieve high humidity is not harmful to dairy cattle. Arrillaga (6) reporting on work done in Puerto Rico, feels that humidity is more of a factor with beef breeds than dairy breeds. The beef breeds he studied were native grades, Brahman grades, and Herefords, while the dairy cattle were Jerseys, Brown Swiss, Guernseys, Ayrshires, and Hol- steins. Their adaptability to thermal stress follows that order. Kibler and Brody (7) report that changes in humidity at temperatures be- low 75° have little effect on the dairy cattle tested. At higher temperatures changes in humidity raised body tem- peratures and respiration rates. These relative humidities ranged from 40 to 75 per cent at temperatures ranging be- tween 75° and 100°. California's desert areas usually have humidities below 40 per cent during the heat of the day and more often than not range between 15 and 35 per cent. Humidity is probably not much of a problem in this area ex- cept as discussed under climatic condi- tions. European cattle lose some water by transpiration through the skin but they do not sweat; this is a primary reason why their rectal temperature increases at air temperatures from 70° to 80° and above. They dissipate excess body heat chiefly by increasing their rate of respi- ration. Much excess heat is lost through evaporation of water in the lungs. Climatic Conditions In the Desert Regions Imperial Valley, Coachella Valley, Palo Verde Valley, and other desert re- [6] gions of California have a mean monthly temperature above 75° for about six months of the year; for nearly four months it exceeds 85° and for two months it is 90°. June and part of July are dry; nights are comfortable. From about July 15 to September 20, the pre- vailing winds from the south and south- east bring moist air from the Gulf of Lower California, and minimum temper- atures at night seldom drop below 70° ; furthermore, they are seldom below 80° for more than four hours. Such condi- tions are oppressive to animals as well as to humans. Temperature is of primary importance in summer livestock management. Figure 1 (page 4) presents average daily maxi- mum and minimum temperatures and noon humidity between April and No- vember, 1946-1952. Figure 2 gives the same data for 1946, showing more clearly how night temperatures rise above the critical temperature (the temperature beyond which cattle body heat rises above normal) and how night tempera- tures coincide with increased humidity in July and August. Most of the figures were compiled at Imperial Valley Field Station.* Humidity is an important climatic ele- ment in the desert regions, but in a dif- ferent way than might be supposed. The air becomes laden with moisture and tends to reflect heat back to the earth instead of letting it dissipate in the upper atmosphere. Since the soil cannot cool, night temperatures rise and the mean temperature for the 24-hour period goes above the critical point. Cattle body tem- peratures rise above normal, with conse- quent reduction of food consumption and decrease in beef and milk produc- tion. What was learned during the studies made on dairy cattle Reaction of Holsteins And Jerseys to Heat Information for this study was col- lected from Imperial Valley dairymen in 1946. It substantiates laboratory findings and data from other countries. Records of milk production, body tem- peratures, and respiration rates of 10 purebred Holstein cows were taken at an Imperial Valley dairy between May and November, 1946. Table 1 shows the inter-relationship of air temperature, milk production, body temperature, and respiration rate. The greatest drop in milk production came in July. The de- crease was 11 pounds daily, or 23 per cent, compared with a 9 per cent drop between May and June. During May and October, body temperatures and respira- tion rates of the cows were normal in the afternoon ; respiration rates ranged from 65 to 67 in the middle of the day. July and August were similar : body tempera- tures averaged 104.8° between 3 and 5 p.m. ; respirations averaged from 67 per minute in the morning to 99 in the after- noon. September was cooler, but body temperature and respiration rates were above normal throughout the day and night. To see if there is any difference in the way high- and low-producing cows react to high temperatures, data for the three highest-producing cows and the three lowest were segregated. In May and Oc- tober they differed little, but during the other four months the high producers consistently averaged 0.3° to 0.8° higher in body temperature. Differences in res- piration rates were not so definite, but the high producers tended to breathe more rapidly. (See table 2, page 9.) * Imperial Irrigation District furnished the missing data. [7] Table 1. Average Milk Product Rates of ion, Body Temperatures, and Respiration Ten Holstein Cows Milk produc- tion Body temp. Respiration rate Daily temp. Date 3-5 3-5 3-5 10-11 1-2 3-5 Av. Maxi- Mini- a.m. p.m. a.m. a.m. p.m. p.m. mum mum pounds deg. F. deg. F deg. F deg. F May 10 . . . 52.9 101.0 101.7 30 42 50 33 39 85 57 June 11 ... . June 12 . . 48.3 101.6 102.3 37 67 65 46 54 104 108 74 68 July 15. . 37.2 102.6 104.1 67 90 * 77 * 112 81 Aug. 8 Aug. 9 30.3 102.5 104.2 71 87 99 87 86 108 107 82 79 Sept. 6 .. . 27.9 102.4 103.4 50 75 75 52 63 108 71 Oct. 7 Oct. 8 22.2 101.0 101.6 29 46 49 38 41 86 86 50 50 This reading was not taken. Similar data were collected on five grade Holstein and five Jersey cows at another dairy; the results are shown in table 3. The Holsteins had higher body temperatures and higher respiration rates than the Jerseys, particularly dur- ing the hotter months. The Jerseys dropped 15.4 per cent in milk production in July, while the Holsteins dropped 27 per cent. From July 29 on, the two groups produced the same amount of milk. As in the first tests (table 2), the high-pro- ducing cows in both groups ran higher body temperatures and respiration rates than the low producers. Color of a Cow's Coat Determines Heat Absorption More radiant heat is reflected from a white surface than from a black one. Consequently, a light-coated cow in the sun absorbs less radiant heat than a dark-coated cow. The relation of coat color to respira- tion rate in cows (a) exposed to direct sunlight and (b) under shade was studied at a Holstein dairy. The dairy kept dry cows and older heifers on pasture during the entire summer without access to shade. On August 8, between 11 a.m. and noon, with an air temperature of 102°, nine cows that were 80 per cent or more white had an average respiration of 105 per minute while five cows 80 per cent or more black had an average rate of 118. This difference is statistically sig- nificant. But when a similar test was made of cows under shade the difference was not statistically significant: On Septem- ber 6, between 10 and 11 a.m. — the air temperature was 103° — ten predomi- nantly white cows showed an average respiration rate of 76, and 10 predomi- nantly black cows showed an average respiration rate of 70. Dry cows, although they had fast res- piration rates, did very little driveling compared to lactating cows. [8] How Temperature Affects Milk Production To learn the effects of daily tempera- tures on milk production, three dairies were studied. Records of Dairies 1 and 2 covered June, July, and part of August; Dairy 3 records covered the months from June to November. Generally, these rec- ords give a good picture of Imperial Valley milk production during the sum- mer. Dairy 1 pastured its purebred Guern- seys most of the year, but corral-fed them in summer. Most of its cows were bred so they would be in the later stages of lactation in summer. Shades provided were made of 10-foot galvanized iron sheets and were about 8 feet high. Dairy 2 had grade cows of all breeds with no particular freshening time. Tree shade was excellent and ample, and the cows were corral-fed (fig. 3). Dairy 3's high grade Guernseys were brought into the Valley in the spring of 1946. Its cows calved in the Valley, the last six in July. They were corral-fed in summer, and had good tree shade but not enough of it. Dairy 1 kept the same number of cows through the test period, while Dairies 2 and 3 added and discarded cows from the milking string without recording dates. Figure 4 shows that in Dairies 1 and 3 there was a decided drop in milk pro- duction on July 9, while No. 2 had a slight rise; its production began to fall off after July 9 but not as rapidly as in the other two. The production drop co- incides with the rise in night tempera- Table 2. Average Milk Production, Body Temperature, and Respiration Rate of the Three High-Producing Holstein Cows Compared to the Average of the Three Low-Producing Holsteins Produc- tion Milk produc- tion Milk production drop Body temp. Respiration rate per minute Date 3-5 a.m. 3-5 p.m. 3-5 a.m. 10-11 a.m. 1-2 p.m. 3-5 p.m. pounds pounds deg. F deg. F May 10 High 61.9* 101.2 101.6 29 49 53 33 Low 44.8 101.1 101.8 32 40 51 34 June 11 High 59.3 2.6 101.8 102.3 43 73 72 47 June 12 Low 44.7 0.1 101.5 102.0 33 72 63 44 July 15 High 43.5 15.8 103.0 104.4 79 91 86 Low 34.0 10.7 102.2 103.9 66 96 84 Aug. 8 High 37.1 6.4 102.6 104.4 70 89 107 89 Aug. 9 Low 27.2 6.8 102.0 103.9 77 91 99 87 Sept. 6 High 35.5 1.6 102.6 103.5 53 80 79 59 Low 25.1 2.1 102.0 102.9 45 70 72 51 Oct. 7 High 27.8 7.7 100.8 101.4 29 53 47 41 Oct. 8 Low 16.4 8.7 101.2 101.7 30 41 51 41 * Records of production were used to differentiate between high- and low-producing cows and did not indicate the stage of lactation. [9] Table 3. Average Milk Production, Body Temperature, and Respiration Rate of Five Holstein-Type Cows Compared with Five Jersey-Type Cows Milk produc- tion — pounds Body temp, in deg. F Respiration rate Date 4-6 a.m. 4-6 p.m. 4-6 a.m. 10-11 a.m. 1-2 p.m. 4-6 p.m. Average Holstein Type May 14 June 17 June 18 July 22 July 29. July 30. Aug. 31 Oct. 3 Oct. 4 . May 14 June 17 June 18 July 22. July 29. July 30. Aug. 31 Oct. 3 . Oct. 4 . . 43.3 101.3 101.9 30 60 54 40 37.4 101.5 102.4 51 56 72 51 27.3 102.6 104.0 74 96 24.3 101.7 103.3 65 105 109 85 23.0 102.0 102.9 77 94 97 82 19.4 101.2 102.0 31 48 53 38 46 58 91 88 43 Jersey Type 29.5 101.3 101.6 27 52 51 36 27.9 101.6 102.1 39 57 69 51 23.6 101.5 103.0 44 •• 82 24.4 101.0 102.6 46 94 84 80 23.2 101.3 102.2 54 76 75 72 19.5 101.4 101.5 23 36 50 30 42 54 76 69 35 tures. From June 1 to July 9 the average minimum temperature was 66.5°, and from July 9 on — for the next 34 days — the average minimum was 79°, with only two nights below 75°. Some dairymen report that cows fresh- ening in summer show an increase in production when the cooler weather of autumn arrives. Dairy 3 did not show such a rise after the break in the hot weather, which came on October 1; in fact it showed a continued drop — per- haps due to advanced lactation — all through October. Records furnished by all three dairies showed several more marked drops in production after the 10] Fig. 3. These eucalyptus trees at Dairy No. 2 provided adequate shade for all cows during most of the day. It was not necessary for them to crowd together and make ground wet and muddy. drop of July 9, and these seem to have coincided with hot nights when tempera- tures were above 75°. About November 10 all the cows of Dairy 3 were given good alfalfa pasture and production then increased. If green pasture could have been provided on October 1 the cows might have increased production at that time, since the weather was cool enough for them to make efficient use of it. Fig. 4. Milk production records of the three dairy herds. The data shown here may be compared with weather data in figure 2 (bottom of page 4). 40 30- Q 20 45 35 25 15 Dair y No. 3 June July August September October November [ii] How Heat Affects Cow's Use of Pasture The following observations were made to learn how summer heat affects the cow's use of pasture and to learn what changes it makes to compensate for the heat. One dairy herd, with access to pasture at all times, was observed during this period (May through October). The senior author made careful observations once a month and combined his findings with those of the owner of the herd. As summer approached the cows used the shade more and more. In May the first cows milked waited in the drylot for the others; then all the animals went out to graze at 7 a.m., for one hour. They rested from 8 to 9 and then grazed again. The first cow came into the drylot at 10; all were in by 11. They ate the hay fed them there, and then stood under the shade. Most lay down from 1 to 3 p.m., and most lay in the shade. The first cows of the milking string went out to graze at 4 p.m.; the others followed as soon as they were milked. The cows were always back in the drylot by 8:30 to 9 p.m. and spent the night there. In June the first cows milked went right out to pasture at about 4:30 a.m., and the first cows were back in by 8. By 9 half the cows were in, but the last ones were not in until 11 a.m. In the evening the first string stayed around the drylot until 5 p.m. During the day about 10 per cent of the cows were lying in the sun. During July, the first cows milked were on pasture by 4:40 a.m., but 60 per cent were in the drylot by 7, and all were in eating hay by 8:30. All the cattle were under the shade by 9:30. The cows ate very little after 9:30 during July and August. At night they did not go out to graze until a little after 5 p.m. August was much the same as July. All the cows were in by 8:30 a.m., and all used the shade. September was a little cooler, and the cows spent a little more time grazing. It was still dark when the first string finished; they remained around the dry- lot until 5 a.m., then started out to graze. The first ones came in at 9, and all were in at 10. In the evening the cows went out at 4:30 p.m. In October the cows went out after sun-up, a little after 5 a.m. Many ate hay during the day, after coming in from the pasture. One day, for example, at 10 a.m., 30 cows were eating; 19 were in the sun and 11 were still on the pasture. All were in the drylot by 10:30 a.m.; at 1 p.m. 16 cows were eating, 74 were lying down, and 10 were in the sun. In the evening the cows went out to graze right after they were milked at 4 p.m. All showed considerably more life and seemed to have improved in appetite. Discussion and Results The climatic record (figures 1 and 2), shows that night temperature and hu- midity rose simultaneously and coin- cided with the first precipitous drop in milk production. The data concerning the relative effects of temperature and humidity seem to indicate that the rise in night temperature to above the critical temperature of the cattle was the primary factor causing body temperature to rise above normal, with consequent reduction of food consumption and decrease in production. The data indicate that dry cows suffer less than lactating cows during the hot months. On the basis of the limited data in table 2, high-producing cows tend to have higher body temperatures and res- piration rates than low producers. Yet there are reasons to presume that ex- tremely high-producing cows must be more efficient heat-eliminators to dispose of the excess incident to heavy food con- sumption and milk production. The dif- ference in heat tolerance of dry and producing cows confirms other observa- tions. The explanation probably lies in the lower food consumption of dry cows. [12 The observation of significantly higher respiration rates in predominantly black animals compared to predominantly white ones exposed to direct sunlight agrees with data obtained in Louisiana and South Africa, where white or light- colored animals reflected 22 to 55 per cent of solar radiation compared with 2 x /2 to 10 per cent by black animals. The comparison of Jerseys and Hol- steins confirms work done at Davis and other stations that Jerseys are more heat- tolerant than Holsteins. The Holstein cows made four adjust- ments to reduce their heat load during July and August: (1) They grazed early in the morning or after 5 p.m. to avoid direct rays of the sun. Most of their non- grazing time was spent under shade. (2) Nearly all cows stood up during the day, thus exposing all the surface possible for radiating excess heat and probably facili- tating respiratory movement. (3) Very little hay was eaten during the middle of the day. This reduced their heat of digestion. (4) Although an accurate measurement of food consumption was impossible, there was an over-all drop that also cut down the heat generated by digestive processes. What was learned about the reactions of beef cattle Crossbreeding Tests Using Hereford Cows To determine if there is any advantage in using Brahman bulls on Hereford cows in a warm climate that is neverthe- less considered satisfactory for Hereford cattle, the following test was organized in cooperation with Louis H. Rochford, president and general manager of the Tejon Ranch, Bakersfield. In 1946 Mr. Rochford selected 101 head of high quality Hereford cows and segregated them in a pasture. From March to September, 1947, two Brahman and two Hereford bulls were placed with these cows. The calves resulting from these matings were purchased by the University late in 1948 and transferred to the Imperial Valley Field Station. In 1948 two Brahman, two Hereford and two Shorthorn bulls were placed with the selected cows on the Tejon Ranch to pro- vide for the additional comparison of Shorthorn-Hereford crossbreds. Calves from these matings were secured in the autumn of 1949. This procedure was fol- lowed again in the 1949 breeding season, and the last group was transferred to Imperial Valley in September, 1950. Table 4 gives data on reproduction, numbers of purebred and crossbred calves obtained, and average weaning weights. Weaning weights of the Here- ford, Braford, and Shorthorn x Here- ford calves averaged 419 pounds. Lack of definite records at weaning age pre- cludes conclusion on the significance of weight differences. Although this area is warm, there was no obvious evidence that the Hereford cows were under stress. The average data for combined steers and heifers in 1949 are affected by vari- ation in the steer-heifer ratio between groups. The six bulls were together in the pasture and had equal breeding op- portunities. In this case at least, the Hereford bulls were the most aggressive and active. All calves made good weaning weights (419 pounds average) ; the Hereford cows showed no particular stress from the heat, and in this test the Hereford bulls were more aggressive and active. Winter Feedlot Test Comparisons In addition to obtaining data to wean- ing at Tejon Ranch, the general plan [13] was to feed out part of the calves in Im- perial Valley during the fall, winter, and spring, when climatic conditions pre- sumably would favor all animals. This was expected to show any inherent dif- ferences in gaining and finishing ability and efficiency of feed utilization when none of the animals were subjected to environmental stress. The remaining cattle were fed on pasture and hay that winter and the following summer, and were finished out in the fall to obtain in- formation on how they compared under hot summer temperatures. All of the 1950 calves were pastured through the winter and spring. The steers were fin- ished in summer and sold in September, 1951. For further comparison, steers and heifers of comparable age and carrying a high percentage of Brahman blood were purchased in 1949. These were much better than the average Brahman then available for feeding. Table 5 presents data for steers and heifers from two feedlot tests of about 200 days each. These were on Brahmans, Herefords, Shorthorn x Herefords, and Table 4. Record of Crossbreeding Test, Tejon Ranch, Bakersfield, California 1948 1949 1950 Cows in breeding herd for calf crop 101 4 57 36 93 92.1 452 423 438 430 101 f 6 44 31 26 101 100 •••§ 99 f 6 42 25 16 83 83.8 434 413 413 389 395 360 Number of bulls * Calves weaned Hereford Brahman-Hereford .... Shorthorn-Hereford TOTAL Percentage calf crop Weaning weights % Hereford steers Brahman-Hereford steers Shorthorn-Hereford steers Hereford heifers Brahman-Hereford heifers Shorthorn-Hereford heifers * The bulls consisted of two Hereford and two Brahman bulls all two years of age in 1947. In 1948 and 1949, two Hereford, two Brahman, and two Shorthorn bulls were used. t During the 1949 breeding season there were 150 cows in the herd. Fifty-one head were sold subsequently. t In 1948 the estimated average age of the Hereford steers was seven to eight months ; the Hereford heifers seven months; the Brahman-Hereford steers and heifers seven months. Thus there may have been a slight advantage in age in favor of the Herefords. In 1949 the average age at weening was about seven months, and in 1950 about six months. The Shorthorn crossbreds average slightly younger in both years, and therefore were lighter at weaning than Herefords or Brafords. Both early and late calves were represented in all groups, but the Brahman and Shorthorn crosses were distributed more throughout the season than were the Herefords. § The steer and heifer calves were not weighed separately in 1949. The combined data for steers and heifers were as follows: Hereford 18 steers, and 26 heifers, average weight 432 lbs. Brahman-Hereford 14 steers, and 17 heifers, average weight 443 lbs. Shorthorn-Hereford 16 steers, and 10 heifers, average weight 423 lbs. [14] Brafords. Table 6 gives these data for both sexes for the 1948-49 test. These figures are more reliable and offer a better comparison, although they cover only the last 104 days of the test. Table 7 contains 1949-50 data on steers and heifers, separately. Figure 5 shows the animals of table 6 at the end of the feed- ing trial. Rate of Gain. Considering the steers and heifers in both winter trials (table 5), Herefords ranked first; Shorthorn x Herefords second; Brafords third; and Brahmans last — in rate and efficiency of gain and in feed consumption. When the sexes were considered separately in the first trial, the difference between the gain of the Hereford heifers and that of the Braford and Brahman heifers was highly significant. The difference be- tween the Braford and Brahman heifers was doubtless real, but with the small numbers were not quite statistically sig- nificant at odds of 20 to 1 for the entire 205 days. During the last 104 days the difference in gain was greater and sta- tistically significant (table 6). The average gains of Hereford and Braford steers in the first trial were essentially equal; both were greater than that of the Brahmans. The difference was of borderline significance for the whole Table 5. Results of Feed Lot Trials with Brahman, Hereford, Braford, and Shorthorn x Hereford Steers and Heifers (All figures are in pounds unless otherwise indicated) 1st year's test — 205 days October 8, 1948-May 1, 1949 2nd year's test — 197 days October 4, 1949-April 29, 1950 Brahman Hereford Braford Hereford Braford 16 487 860 1.89 S XH No. of animals * 12 433 767 1.64 12 501 934 2.15 12 504 896 1.91 16 492 922 2.18 10 455 873 2.10 5.48 3.75 5.39 2.62 Av. initial wt Av. final wt AV. DAILY GAIN Av. daily feed Grain f 4.68 3.13 6.88 6.78 3.71 8.61 19.10 6.23 3.33 8.45 18.01 5.63 3.81 5.34 2.59 5.53 3.72 5.22 2.56 Dry beet pulp Alfalfa hay J Sudan and barley hay . TOTAL 14.69 17.37 17.03 17.24 Feed/100 lb. gain Grain 285 190 396 315 172 379 326 174 416 258 174 245 119 292 197 276 135 260 178 256 124 818 Dry beet pulp Alfalfa hay Sudan and barley hay . TOTAL 871 866 916 796 900 * The first year only 11 animals were in the Brahman and Hereford lots during the first 101 days. There were 12 head in each lot during the last period. t The grain was barley although some milo was included in the ration during the last part of the first year's test. X Some sudan hay and barley hay was fed with the alfalfa hay during the first year. [15] 5 Tuiiiwiiiir Fig. 5. From left to right are shown Brahman, Braford, and Hereford steers at the Table 6. Comparison of Brahman, Hereford, and Braford Steers and Heifers During the Last 104 Days of the 205-Day Feeding Period Jan. 17, 1949-May 1, 1949 (All figures are in pounds unless otherwise indicated) Group 1 Brahman steers Group 2 Brahman heifers Group 3 Hereford steers Group 4 Hereford heifers Group 5 Braford steers Group 6 Braford heifers Number in lot Av. initial wt 7 641 816 1.68 3.49 1.63 4.06 5.24 1.73 207 97 241 311 103 5 567 698 1.26 6 713 943 2.21 6 719 924 1.97 6 743 979 2.26 6 634 814 1.73 Av. final wt AV. DAILY GAIN Av. daily feed Barley Milo 2.54 1.44 3.85 4.81 1.29 4.84 2.52 4.59 6.51 1.66 4.96 2.52 4.86 6.53 1.56 5.14 2.50 4.94 7.09 1.68 3.85 2.14 3.65 6.26 1.31 Dry beet pulp Alfalfa hay Barley hay Feed/100 lb. gain Barley 202 114 306 382 103 219 114 208 295 75 252 128 246 330 79 227 110 218 313 74 942 223 124 211 362 76 Milo Dry beet pulp Alfalfa hay Barley hay TOTAL 959 1,107 911 1,035 996 [16] nclusion of the 1948-1949 winter feeding test which was conducted for 205 days. Table 7. Comparison of Braford, Hereford, Shorthorn x Hereford Steers and Heifers on Full Feed for the 197-Day Feeding Period, October 4, 1949-April 29, 1950 (All figures are in pounds unless otherwise indicated) Hereford steers Hereford heifers Braford steers Braford heifers S XH steers S XH heifers No. of animals 8 504 959 2.31 8 479 884 2.06 8 474 859 1.96 8 499 860 1.83 5 471 912 2.19 5 437 835 2.02 Av. initial wt Av. final wt AV. DAILY GAIN Av. daily feed Barley Dry beet pulp Alfalfa hay 5.75 3.88 5.52 2.64 5.52 3.73 5.16 2.53 5.56 3.74 5.33 2.61 5.50 3.71 5.12 2.51 5.55 3.80 5.78 2.70 5.41 3.70 5.00 2.53 Sudan and barley hay . TOTAL 17.79 16.94 17.24 16.84 17.83 16.64 Feed/100 lb. gain Barley 249 168 239 114 268 182 251 123 284 191 272 133 300 202 280 137 254 174 264 124 268 183 248 125 Dry beet pulp Alfalfa hay Sudan and barley hay . TOTAL 770 824 880 919 816 824 [17] period but was highly significant during the last 104 days of the test (table 6) . In the 1949-1950 trials (table 7) there was no great difference between the gains of the Herefords and the Short- horn x Hereford crossbrcds, although the latter averaged slightly lower. The gains of the Herefords, both steers and heifers, were significantly larger than the Bra- fords'. The steers and heifers were fed for equal periods in each trial, and since the heifers are faster maturing they were fatter at slaughter time as the carcass data show. The Hereford heifers, par- ticularly, were highly finished, were ready for marketing several weeks before the steers, and their rate of gain de- clined during the last of the feeding pe- riod. Both the Braford and Brahman heifer groups in the first trial were nervous and excitable; doubtless this fact affected their gains. The Braford steers quieted down after getting on feed. The Brah- man steers, although alert and active, had quiet dispositions and most of them appreciated petting. Economy of Gain. There was no significant difference in feed cost for 100 pounds gain between the Herefords and Shorthorn-Hereford crossbreds. Both of these groups required less feed per pound of gain than the Brafords and Brahmans. This appears to be highly significant, since not only did the Here- fords and Shorthorn x Herefords require less total feed per pound of gain but also their gain contained somewhat more fat, which has a higher energy content than lean tissues. The higher carcass yield of the Brahmans and Brafords may offset their apparently lower efficiency based on live-weight gain. The feed cost for 100 pounds of gain was uniformly greater for the heifers than for the corresponding steers. This may be accounted for by the higher av- erage degree of fatness of the heifers. When two such groups are fed to equal finish, and the heifers marketed earlier, there is usually no significant difference in economy of gain compared with steers of similar age and breeding. Feeding Habits. Herefords and Brahmans exhibited a marked difference in the way they consumed feed. The latter ate more slowly and not so much at one time, while the Herefords gulped their grain. The Braford cattle ate more like the Herefords. The average daily food consumption for each 100 pounds live weight in both trials was: Brahman, 2.21; Braford, 2.48; Hereford, 2.46; and Shorthorn-Hereford cross, 2.60. Some bloating occurred during the first trial. It was more noticeable among the Brahmans but not severe and appar- ently had little effect on gain. These two feed lot tests show that Herefords ranked first; Shorthorn x Herefords second; Brafords third; and Brahmans last in rate and efficiency of gain and in feed consumption. Feed cost for 100 pounds of gain between the Here- fords and Shorthorn-Hereford crossbreds were about the same and both these groups required less feed per pound of gain than the Brafords and Brahmans. However, the higher carcass yield of the Brafords and Brahmans may offset this lower efficiency of gain. Summer Feedlot Test Comparisons Only the steer calves from the 1950 group were fed out during the summer; the heifers were used for other tests. Table 8 summarizes this feeding trial. Figure 6 shows the Brafords and Short- horn x Herefords at the end of the ex- periment. Rates of gain. Over-all results were good for the one drylot summer feeding trial. Braford, Hereford, and Shorthorn x Hereford steers all gained a little more than two pounds daily. High summer temperatures definitely affected these gains during July and August. The Bra- fords and Herefords had a daily gain of [18] Fig. 6. (Left) Braford and (right) Shorthorn x Hereford steers at the conclusion of the 122-day summer feeding test period. Table 8. Summer Comparison of Braford, Hereford, Shorthorn x Hereford Steers on Full Feed for 122 Days, May 15- September 14, 1951 (All figures are in pounds unless otherwise indicated) Mid- summer July 10-Sept. 3 Summer May 15-Sept. 14 Braford Hereford S XH Braford Hereford S XH No. of animals 10 905 1,006 1.80 8 970 1,070 1.79 6 958 1,039 1.45 10 759 1,027 2.20 8 824 1,087 2.15 6 812 1,067 2.09 Av. initial wt. Av. final wt AV. DAILY GAIN. . Av. daily feed Barley 5.73 3.86 10.77 1.89 5.73 4.06 9.60 2.34 5.40 3.32 6.11 4.03 5.54 3.63 11.33 1.98 5.38 3.72 10.74 2.36 5.37 3.32 9.16 3.53 Dry beet pulp Alfalfa hay Barley hay TOTAL 22.25 21.73 18.86 22.48 22.20 21.38 Feed/100 lb. gain Barley 318 214 598 105 320 227 536 131 373 229 421 278 252 165 516 90 250 173 499 110 257 159 438 169 Dry beet pulp Alfalfa hay Barley hay TOTAL 1,235 1,214 1,301 1,023 1,032 1,023 [19] 1.80 and 1.79 pounds respectively. The Shorthorn x Here fords gained only 1.45 pounds and showed more distress (table 8). Economy of gain. For the three breeds of steers the economy of gain in the summer feeding trial was almost identical. To make 100 pounds of gain during mid-summer, the Brafords and Herefords needed about 200 pounds more feed and the Shorthorn x Herefords about 300 pounds more than the same groups needed for a 100-pound gain in the over-all period (May 15-Sept. 14). Although strictly comparable data are not available, tables 6, 7, and 8 indicate that more feed is required for a pound of gain in summer than in winter. Feeding habits. The Shorthorn x Hereford steers consumed less feed in July and August. It was a problem to keep them on feed. In the evening they often had to be driven to the feed trough. They showed marked distress, but the Braford and Hereford groups did not seem especially uncomfortable. The Herefords had a faster respiration rate than the Brafords. Both of these lots were always ready to eat at feeding time, and the Herefords' food consumption was very close to that of the Brafords (table 8). Tests on Pasture — Summer and Winter Comparison of Hereford, Braford and Shorthorn x Hereford cattle : Tests were conducted at the Field Station to compare pasture and roughage utiliza- tion during the seasons, particularly in the hot summers. Pastures vary at differ- ent times of the year in Imperial Valley. Alfalfa is the most common irrigated- pasture crop. Many livestock men reno- vate, fertilize, and then plant barley or oats in their alfalfa fields about October 1 for winter pasture, and it is usually ready for grazing about December 1. Livestock gains in December and Jan- uary are often less than in the spring. This difference is due partly to the excess of water in feed at that time. Spring pas- tures in the Valley are exceptionally strong; cattle often make gains of 1.75 to 2 pounds per head per day. In sum- mer the pasture growth slows somewhat, and there is always the danger of scald- ing alfalfa on the heavier soils. The pasture tests were as follows : Group 1 consisted of 12 Herefords and 12 Braford calves from the Tejon Ranch, each lot including six steers and six heifers. These animals were received De- cember 7, 1948. The data are summa- rized in tables 9 and 10. Group 2 — Tejon Ranch yearlings — consisted of 16 Hereford and eight Bra- ford steers, purchased May 5, 1949. Data are in tables 11 and 12. Group 3, the last lot of cattle received from Tejon Ranch, were pastured from September 27 to May 15, and the steers were fed in the dry lot during the sum- mer (table 8). Conclusions This summer feedlot experiment shows that Herefords can make good gains during the summer if they have good shades and airy corrals. Daily gains drop somewhat in July and August and the feed required per 100 pounds of gain is higher for summer than for winter feeding, but Brafords, Herefords, and Shorthorn x Herefords all required about the same amount of feed per 100 pounds of gain during this period. Short- horn x Herefords showed considerable distress during July and August and were hard to keep on feed. In the summer of 1948 a preliminary test was made with a fourth group. Eight head of good quality Braford steers from Texas were compared with 21 Hereford steer calves transferred from the San Joaquin Experimental Range herd. The Hereford calves were born the preceding fall, while the Bra- fords presumably were several months older. Since these cattle were fed to- [20] Table 9. Comparative Seasonal Gains of Herefords and Brafords (1948-1949) (All figures are in pounds unless otherwise indicated) Winter, hay in dry lot Dec. 7- March 4 (88 days) 510 655 1.65 Spring, pasture March 5- June 13 (101 days) 655 839 1.82 Summer, pasture June 14- Sept. 14 (93 days) Fall, hay and grair in dry lot Sept. 15- Oct. 22 (37 days) Average all periods (319 days) Hereford steers 6 head Av. initial wt. . 839 987 1.58 802 939 1.47 987 1,080 2.51 1.79 1.57 Av. final wt AV. DAILY GAIN Hereford heifers 6 head Av. initial wt 513 629 1.32 629 802 1.71 939 1,015 2.08 Av. final wt. AV. DAILY GAIN Braford steers 6 head Av. initial wt 461 598 1.56 598 815 2.15 815 1,006 2.05 1,006 1,090 2.29 1.97 Av. final wt AV. DAILY GAIN Braford heifers 6 head Av. initial wt 444 558 1.30 558 744 1.84 744 912 1.80 912 993 2.19 1.72 Av. final wt AV. DAILY GAIN Av. 24 head Av. initial wt. 528 610 1.47 18.49 1,259 610 800 1.89 3.44 183 800 961 1.73 3.45 200 961 1,045 2.27 11.02 6.53 486 288 f 1.80 7.35 0.84 408 46.8 Av. final wt AV. DAILY GAIN Av. daily feed* Alfalfa and grain hay Concentrates Feed/100 lb. gain* Alfalfa and grain hay Concentrates * Feed records do not include the first 32 days of the test. t Barley and beet pulp was the concentrate feed during this period. [21] Table 10. Sale and Slaughter Data on Braford and Hereford Steers and Heifers (1948-1949) Braford steers Hereford steers Braford heifers Hereford heifers No. of animals 6 1,090 4.93 3.33 25.25 5 good, Icomm. 61.47 6 1,080 5.53 3.06 26.50 6 good 59.35 6 993 5.98 3.71 24.00 5 good, 1 comm. 62.51 6 Av. wt. at home, lb Percent shrink to Los Angeles . . Percent shrink on selling wt Selling price, cents 1,015 5.14 1.28* 24.00 Grade Not graded Dressing percentage (3 percent shrink) 58.94 * The Hereford heifers were not sold until 11 a.m. and had taken on a good fill. The other groups were sold early in the morning. gether, no comparative feed consumption data were obtained. For the period of hot weather, July 28 to September 20, the Brafords gained at the rate of 1.99 pounds daily, the Herefords 0.85. The final weight of the Brafords was 691 pounds, the Herefords', 591. The differ- ence in initial weights averaged 41 pounds. Group 1 . During winter dry-lot feed- ing on hay the 12 Herefords outgained the 12 Brafords. In the spring and sum- mer pasture period the situation was re- versed, the difference being greatest dur- ing the hot weather, June to September. The average consumption of dry hay in addition to pasture for both groups was 3.4 pounds per head daily. The pasture was mainly alfalfa with a small amount of alta fescue. These cattle were marketed in October after 37 days in dry lot on a hay and grain ration. The total gain for the 319-day period was: Hereford steers, 570 pounds; Braford steers, 629 pounds; Hereford heifers, 502 pounds; and Braford heifers, 549 pounds. All cattle except one Braford steer and one Braford heifer graded good (grade de- scription prior to 1951). The total aver- age concentrates used per head was 242 pounds (table 9) . This test shows the possibilities for producing good grade long yearling beef with a minimum of concentrates through promotion of continuous growth and development after weaning by win- tering well and providing good pasture during the summer, followed by a short dry-lot period in the fall. Producing quality beef with a minimum of concen- trates is a major problem facing future beef production. Herefords proved more efficient on full feed in dry lot both in this and in the dry-lot feeding trials. Brafords out- gained Herefords, however, on pasture during both the moderate and high tem- perature periods. Their average daily gain on pasture and roughage was com- parable to that of their mates on full feed of concentrates in dry lot during the fall, winter, and spring (tables 5, 6, and 7). It is possible the Brafords and Herefords were not equally adapted dur- ing the winter even under the very mild conditions of Imperial Valley. The indi- cations are, however, that Brafords were especially efficient in pasture ulitization. From August 5 to September 14, when day and night temperatures were high, there was a drop in gain of all lots as shown by the tabulation on page 23. [22] Average Daily Gain — in Pounds Hereford Hereford Steers Heifers June 14-Aug. 4 2.03 1.71 Aug. 5-Sept. 14 1.02 1.15 Difference 0.91 0.56 Sraford Braford Steers Heifers 2.60 2.28 1.35 1.20 1.25 1.08 Quality of pasture as well as climatic conditions may have been involved. It would seem that during the extreme heat of summer (Aug. 5-Sept. 14) the Bra- fords were somewhat affected by high temperatures, although not as much as the Herefords. Sale and slaughter data are in table 10. Again there was no consistent differ- ence in transit shrinkage between Here- fords and Brafords. Considering the dif- ference in yield of more than 2 per cent in favor of the Brafords and the carcass data (see page 31), the spread of $1.25 Table 1 1. Comparative Seasonal Gains of Hereford and Braford Steers (1949-1950) Spring pasture : May 13- June 9 (28 days) Summer pasture : June 10- Sept. 15 (98 days) Fall, hay in dry lot: Sept. 16- Nov. 1 (47 days) Winter hay and grain dry lot: Nov. 2- Jan. 7 (66 days) Average of all periods (239 days) Hereford steers (16 head) Av. initial wt. 549 601 1.89 601 727 1.28 727 825 2.07 825 967 2.16 1.75 Av. final wt. . AV. DAILY GAIN Braford steers (8 head) Av. initial wt 481 530 1.74 530 729 2.03 729 828 2.33 831* 960 1.95 2.04 Av. final wt AV. DAILY GAIN Av. of 24 head Av. initial wt 526 578 1.84 578 728 1.53 728 829 2.16 827* 965 2.10 1.84 Av. final wt AV. DAILY GAIN Av. daily feed Alfalfa and grain hay Concentrates 3.54 6.70 25.7 24.11 9.63 14.77 2.57 Feed/ 100 lb. gain Alfalfa and grain hay Concentrates 193 437 1,192 1,151 460 f 801 140 * Only 7 Brafords during feedin t A barley-and-beet-pulp concer g period. One animal was sol ttrate was fed during this per d. iod. 23 per hundred pounds in favor of the Here- fords was probably not justified. Group 2. As table 11 shows, Here- fords outgained Brafords slightly during spring pasturing. During the hot weather (June to September), however, there was a conspicuous difference in favor of the Brafords and also, to a lesser ex- tent, during the fall period on roughage consisting of alfalfa and grain hay. The gains of 2.07 and 2.33 pounds respec- tively for the Herefords and Brafords on roughage alone were remarkable during this 47-day period. Other records at the Station showing gains higher than nor- mally expected by young animals on roughage alone emphasize the possibili- ties of high-quality hay and suggest the need for an explanation. These cattle were marketed in January, 1950, through the Los Angeles Union Stock Yards. Although they carried about the same finish as those sold the previous October, they were held by the buyer for further feeding, and no slaughter data were obtained. The selling data are shown in table 12. Evidence from these trials indicates that Hereford cattle brought into the area during the fall and gradually ac- customed to the climate do better during subsequent hot weather than those brought in early in summer. Group 3. From September 25 to Oc- tober 24, all 53 animals grazed on indi- vidual plots of Sudangrass, tall fescue, Hardinggrass, Dallisgrass, Rhodesgrass, blue panica, Paragrass and Napiergrass. The European cattle did poorly, averag- ing from 0.10 pound of gain per head per day for Hereford steers to 0.47 pound per day for Shorthorn x Hereford heifers. Braford steers and heifers aver- aged about a pound a day. This again shows how Brafords efficiently use rather poor quality pasture. After the first month this group had good alfalfa pasture or alfalfa with bar- ley planted in it for winter grazing. In the spring all the animals were on fescue pasture for not more than eight days when other pastures were too wet to graze. Steers and heifers were pastured separately during the spring except for the eight-day period on fescue. Table 13 shows comparative seasonal gains of Hereford, Braford, and Short- horn x Hereford steers and heifers for fall, winter, and spring pasture periods. The steers were fed out during the sum- mer as reported previously, while the heifers were retained for other tests. The hay and grain fed these animals while on pasture during the three seasons (table 14) ranged from 3.73 to 4.85 pounds of hay per head per day, with a very small amount of barley. The fall grazing period showed an av- erage gain of 0.84 pounds per head per day for all animals. This poor showing was due partly to the poor pasture dur- Table 12. Selling Data on Braford and Hereford Steers Braford steers Hereford steers No. of animals 7 960 6.22 24.50 16 967 5.91 25.00 Av. wt. at home — pounds Percent shrink on selling weight Selling price for hundred pounds, dollars Note: The Hereford steers carried the same finish as those in the 1948-1949 group; however, these went to a packer for further feeding. Hence slaughter data were not obtained from this group. [24] U) ffi oc K oc V. X CO t- n th •O tH *0 z o m o m •g g ■c 2 ft p. ■u CO WiH T> "tf t- T3 "* c 3 cS ?? O oc 5 ^& u o -i— IC s 03 cog "eel o to ff 1- M^H O CO l> i- ih o m iH O^ o co oc i- 43 O lO H i- &. Ih « a W i- 4> X iH iH t- **• CO oc CO t- k X a oc oc a cn cc X X co co t> T- x 00 O CO H t- -^ (N O c k 1 o CO "^ CC 2 i CO ■^ lO X 0) D ^5 0) C75 ft iH 'C *o c a cc oc a cn CO n « M 3 X CO o cc c X 00 t- O 1 o — o o CO t> CO C5 a 1 s CO Tj< *tf T3 OJ CO CO ^ O Ih O a> O tH t-i ^ i_ 01 r-f 0) rH rt X a ft w N "O oc » W N TJ ^ -a © ^ k! M CR 4> ^" h! *H a JS a> 3 (h cS > 373© to CO w o O 00 « iH C* W c M c8 > wcCT o co o 'S J3 > -o Ih ■1- «2 *g Li 8 M Q. .l E M hi to u • co a fc 'S g CO 5 H 3 •CO "S CO b ft CO CO "e3 += _0) X I t t * 3 *3 5 II! cd T3 ec 3 CO CO aa CO o 5^ O* > > fc < < > o:§cg o > > Jz; < < > < Oh ing the first month. In winter when the animals were on alfalfa and barley pas- ture they averaged 1.65 pounds per day but in spring the steers made 1.91 pounds while the heifers gained 1.71 pounds per day. During 231 days on pasture these ani- mals gained 351 pounds per animal, av- erage weight for the period being 592 pounds. They required about one acre per animal. After April 20, 1953, the pastures began to produce more than they could consume, and by May 15, when this phase of the test was com- pleted, some of the plots were cut for hay. In these four tests Braf ords made daily gains of 0.3 to 1.1 pounds more than Herefords during the summer pasture period. The dry-lot feeding trials at the conclusion of these pasture tests again showed the Herefords more efficient. Sev- eral periods in these tests showed that Brafords were very efficient in their use of poor quality pasture. All groups made gains of 1.5-2.0 pounds daily during winter and spring pasturing. Gains of 2.0 pounds a day on roughage alone in- dicate that at least some of the hay had a high feeding value. Alfalfa Pasture Better than Alta Fescue Alfalfa is the major irrigated-pasture crop in the desert, and Imperial Valley usually has some 160,000 acres every year. Alta fescue, under test on this Sta- tion for a number of years, showed enough promise to warrant a field test. In September, 1950, a 20-acre pasture was planted in 6-inch rows at the rate of 10 pounds of seed per acre, and a good Table 14. Seasonal Food Consumption for Animals in Table 13 (1950-1951) (All figures are in pounds unless otherwise indicated) Fall Winter Spring Sept. 27- Nov. 21 56 days Nov. 22- Feb. 20 91 days Steers Feb. 21-May 15 83 days Heifers Feb. 21-May 17 85 days No. of animals 58 417 464 0.84 57 464 613 1.65 25 634 793 1.91 28 Av. initial wt. 596 Av. final wt. 742 AV. DAILY GAIN 1.71 Av. daily feed Barley Alfalfa hay 0.63 4.17 0.12 1.77 2.11 1.00 0.34 3.39 0.33 4.52 Barley hay TOTAL 4.92 4.88 3.73 4.85 Feed/100 lb. gain Barley 74 497 15 107 128 61 18 177 19 Alfalfa hay 264 Barley hay TOTAL 586 296 195 283 [26] Table 1 5. Comparison of Fescue and Alfalfa Pasture with Hereford Steers, December 14, 1951 -June 18, 1952 (All figures are in pounds unless otherwise indicated) Fescue Alfalfa Winter Dec. 14- Feb. 7 56 days Early spring Feb. 8*- March 24 46 days Spring March 25- June 17 84 days Winter Dec. 14- Feb. 7 56 days Early spring Feb. 8- March 24 46 days Spring March 25- June 18 85 days No. of animals 21 472.1 529.6 1.03 21 529.6 623.4 2.04 21 623.5 694.8 0.85f 21 472.4 556.6 1.53 21 556.6 650.7 2.05 21 650.8 768.0 1.38f Av. initial wt. Av. final wt AV. DAILY GAIN. . . . Av. daily feed Alfalfa hay 4.22 0.92 12.02 2.87 0.54 3.08 3.65 0.95 2.05 0.54 2.70 Barley hay Barley and milo TOTAL 5.14 15.43 3.08 4.60 2.59 2.70 Feed/100 lb. gain Alfalfa hay 411 90 589 141 27 363 239 62 100 27 196 Barley hay Barley and milo TOTAL 501 757 363 301 127 196 * Between February 8 and March 24 the fescue steers were fed alfalfa hay in dry lot — no growth on the f During the time on pasture the fescue steers' average gain was 0.92 lb. while the alfalfa steers' gain was 1.62 lb. per head per day. stand was produced. In the fall of 1951 a pasture study was started comparing the fescue with an alfalfa pasture that was renovated in late September and re- seeded with 5 pounds of alfalfa, 20 pounds of oats, 20 pounds of barley, and 20 pounds of wheat per acre for winter pasture. At the time this field was seeded it was fertilized with 100 pounds of 46 per cent phosphate and then irrigated on October 6. The fescue pasture was fer- tilized three times during the pasture period and each time received 40 pounds of nitrogen per acre. In early November, 42 head of good quality Hereford steers averaging 450 pounds were secured. Between November 21 and December 14, all 42 steers were pastured on fescue since the alfalfa pas- ture was not quite mature enough for grazing. The animals made an average daily gain of 0.87 pounds per head per day and received 2.30 pounds of barley hay and 0.42 pounds of barley per head per day in addition to their pasture. On December 14 all animals were weighed again and divided into two groups — one group going on the 20 acres of fescue and the other on the 20 acres of alfalfa and grain. Results of this test are shown in table 15. Between February 8 and March 24 the weather was rather cold and the fescue made little growth; so the fescue steers were fed alfalfa hay in dry lot for this 46-day period. During this period on hay the fescue group [27] gained 2.04 pounds per head per day, but the group on alfalfa and grain pas- ture made 2.05 pounds with 2.59 pounds of supplemental feed. When both groups were on pasture the alfalfa lot consistently averaged a half pound more gain per head per day than the fescue group. Counting the original 23 days when all the animals were on the fescue pasture, the fescue produced 3,528 pounds of beef, while the alfalfa produced 6,197 pounds during these 187 days with almost the same amount of supplemental feed. Figure 7 shows fescue and alfalfa steers at the end of the test. The fescue pasture, slightly smaller than the alfalfa field, measured 15.8 net acres; the alfalfa plot had 16.9 acres. Thus the fescue field, during the time the cattle were pastured (140 days) , had 1.33 head of 548-pound animals per acre, and the alfalfa pasture had 1.24 head per acre of 579-pound animals until April 18. From April 18 to June 18 the 21 head of steers were pastured on only 10 acres of alfalfa, and during this time 2.1 head of 721-pound animals were pas- tured per acre. The pounds of beef pro- duced per acre is the final yardstick of any pasture experiment. Thus the fescue field produced 223 pounds of beef per acre while the alfalfa pasture made 422 pounds of beef per acre. Since only 10 acres of the 17 acres of alfalfa pasture was utilized during the last 60 days of the test there was only an average of 14.7 acres actually used for the experiment. This would give the alfalfa pasture a carrying capacity of 1.43 head per acre of 620-pound animals for 187 days, with an average of 3.19 pounds of supple- mental feed per day. Recent work by Station Agronomist Shofner B. Boswell (now at Riverside Experiment Station) and Dr. M. L. Peterson, of the Department of Agron- omy at Davis, showed Africa alfalfa to have a yield per acre of 102,500 pounds green weight for 10 clippings during the year; the five fescues tested showed a yield range of green material from 42,000 to 70,800 pounds with the same number of clippings. Fescue 144 was the high yielder followed by alta fescue, Kentucky 31 fescue, Goar's fescue and 4-36 fescue. Considering daily gains, carrying ca- pacity, beef produced per acre and pro- duction of green forage as shown by clipping tests, it is apparent that alfalfa pasture is superior to alta fescue in this area. „teMmmmm Fig. 7. (Left) Hereford steers pastured on alfalfa and alfalfa and grain and (right) steers pastured on fescue; both at the end of the winter feeding tests. [28] Tropical Grasses Seem Unsuitable Two tropical grasses were tested in one-acre plots and grazed by cattle for two years: Paragrass (Panicum purpura- scens) , which grows in Florida, southern Texas and other Gulf states; and Napier- grass {Pennisetum purpureum) , also called Elephantgrass — a native of Africa. Napiergrass is a perennial with much the same habits as sugar cane. These grasses are perennials but are dormant all winter. Although they fur- nish some pasture from May to the middle of November, their rate of growth is quite slow except in July and August. Cattle like both grasses but because of their limited production the grasses do not seem well suited to Imperial Valley and similar regions. Summer Grazing Habits of Beef Cattle Experiment station personnel in many parts of the world have observed that Brahmans and their crosses spend more time grazing on hot summer days than do European breeds. To check these ob- servations under local climatic condi- tions, a herd composed of Brahmans, cross-bred Brahmans, Santa Gertrudis type, Herefords, and Shorthorns was ob- served from April through October, be- tween 5 a.m. and 6 p.m. All of the cattle had access to a large drylot with ade- quate shade. In April and May all animals had four observable grazing periods. The first was from early morning until about 7 a.m. The time between 7 and 9 a.m. was spent in the drylot, and many of the Herefords and Shorthorns spent this time under the shade. The second graz- ing period was between 9 and 10:30 a.m. ; from then until 1 p.m. the animals rested in the drylot. All of them grazed a third time between 1 and 2 p.m., rest- ing in the pasture about two hours there- after. At 4 p.m. they grazed again, until 6 p.m. After May 16 many of the Here- fords and Shorthorns missed this third grazing period and did not go out to graze until about 4 p.m. Differences develop. In June a dif- ference in grazing habits of the various breeds began to develop. Almost all of the Herefords and Shorthorns were in the drylot by 7 a.m., then the Santa Gertrudis came in, and last of all the Brahmans. All cattle were in by 9 a.m. Most stayed in the drylot until 1 :30 p.m. missing their second grazing period. About half of the cattle grazed for one- half hour; then all Herefords and Short- horns came back to the shade, and many of the others lay down in the pasture. By 3 p.m. half of the Brahmans were grazing but all Herefords and Shorthorns were still under the shades. At 3 p.m. half of the Brahmans were grazing but all Herefords and Shorthorns were still in the shade, and 80 per cent of them were lying down. By 3:30 p.m., 90 per cent of the animals were grazing, and at 4:30 p.m. all were grazing. Grazing habits for July and August were similar but most of the observations were taken in August. All the animals were in the drylot by 8 a.m. and their order of arrival was the same as in June. Most stayed in the drylot until 1 p.m.; then 75 per cent of the Brahmans and 20 per cent of the Santa Gertrudis grazed for a while. Some rested in the pasture while others came back to the drylot. After 4 p.m. the Herefords and Short- horns began going out to graze. September was much like June: the Herefords and Shorthorns did not begin to graze until after 4 p.m. While October was somewhat like May, the October pas- ture was very short and considerable hay was being fed so it was difficult to make comparisons. These observations show that the Herefords and Shorthorns spent most of the time between 7 a.m. and 4 p.m. under the shades during July and August. 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A high roughage diet in summer will produce a large amount of heat that cannot be used for meat pro- duction, whereas a ration with some con- centrate will produce about the same amount of digestible energy but less waste heat; consequently more meat is produced. This difference has been dem- onstrated on the Station several times in feeding trials. The following rough cal- culations further illustrate what takes place in the body on a roughage and a roughage concentrate diet (table 18). Net Energy The metabolizable energy of a feed represents the energy remaining after deducting the energy lost in the feces and urine. The heat increment is the heat produced in the body due to the in- creased metabolism brought about by consumption of food. This heat is only of value to the animal during cold weather. It is a detriment during hot weather. By subtracting the heat incre- * F. B. Morrison, Feeds and Feeding, 21st edition. ment from metabolizable energy, net energy is obtained, which is the energy actually available to the animal for maintenance and production of body gain. It will be noted from the calcula- tions that this figure is considerably lower for the roughage groups than for the concentrate lots. The concentrate lots seem able to take care of a little more total heat and still end up with more energy available for productive purposes. Finishing It is probably not wise to put a high finish on cattle during the summer but to plan operations so they will be finished just before summer starts or after the hot weather. During the summer cattle show a drop in food consumption on any ration tested thus far, and, at least when hand-fed, it is sometimes difficult to get the concentrates very high and keep the animals on feed. Yet they do gain, as the table indicates. Feed-yards in the Valley report good gains during the summer even though there is a drop in food con- sumption and rate-of-gain during the hottest periods. Even though a strictly roughage diet is not desirable for summer feeding, good quality alfalfa hay that has plenty of phosphorus has given excellent results during the cooler months. Several tests have shown this, but to cite one example : Consuming an average of 17.72 pounds of good alfalfa hay per day, five Hereford steers started with an average weight of 391 pounds. Fed for 187 days in fairly cool weather, they gained an average of 1.99 pounds per day and weighed an average of 763 pounds at the end of the test. ACKNOWLEDGMENTS The authors gratefully acknowledge the assistance of the following men and organizations whose cooperation made these experiments possible: Tejon Ranch Company, Bakersfield, Sterling Meat Company and Safeway Stores Inc., of Los Angeles. Members of the Agricultural Extension Service of Imperial County, Members of the Animal Husbandry Department at Davis, Harold Hunt, Keith Mets, Don C. Bassett, Fidel Gomez, Joe Bishop, and H. G. Farnsworth, farmers in Imperial Valley. [35] REFERENCES (1) Regan, W. M. and G. A. Richardson Reaction of the dairy cow to changes in environmental temperature. Journal of Dairy Science 21 : 73-79. 1938 (2) Ragsdale, A. C, Samuel Brody, H. J. Thompson, and D. M. Worstell Influence of temperature, 50° to 105° F. on milk production and feed consumption in dairy cattle. Mo. Exp. Sta. Res. Bui. 425. 1948 (3) Kibler, H. H. and Samuel Brody Environmental physiology with special reference to domestic animals. Mo. Exp. Sta. Res. Bui. 464. 1950 (4) Bonsma, J. C, G. D. H. Scholtz, and F. G. J. Badenhorst The influence of climate on cattle. Fertility and hardiness of certain breeds. Farming in S. Africa 15, 7. 1940 (5) Seath, D. M. and G. D. Miller High humidity not harmful to cows. Dairy Res. Dig. (La. Sta.) 3 (3) 1945. (6) Arrillaga, C. G., W. L. Henning, and R. C. Miller The effect of environmental temperature and relative humidity on acclimation of cattle to the tropics. Jour, of Anim. Sci. 11: 50-59. 1952 (7) Kibler, H. H. and Samuel Brody Influence of humidity on heat exchange and body temperature regulation in Jersey, Holstein, Brahman and Brown Swiss cattle. Mo. Exp. Sta. Res. Bui. 522. 1953 (8) Black, W. H., A. T. Semple, and J. L. Lush. 1934 Beef production and quality as influenced by crossing Brahman with Hereford and Short- horn cattle. U.S.D.A. Technical Bulletin No. 417 (9) Kelly, C. F., T. E. Bond, and N. R. Ittner Thermal design of livestock shades. Agr. Eng. 31: 601-606. 1950 (10) Ittner, N. R. and C. F. Kelly Livestock shades. Jour, of Anim. Sci. 10: 184-194. 1951 7Jm-9,'54(4878)RMB