EFFECTS OF DIETARY ENERGY, FREE CHOICE ALFALFA HAY AND MASS MEDICATION ON CALVES SUBJECTED TO MARKETING AND SHIPPING STRESSES 1

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1 EFFECTS OF DIETARY ENERGY, FREE CHOICE ALFALFA HAY AND MASS MEDICATION ON CALVES SUBJECTED TO MARKETING AND SHIPPING STRESSES 1 Glen P. Lofgreen, L. H. Stinocher 2 and H. E. Kiesling 2 New Mexico State University, Clayton Livestock Research Center, Clayton Summary Five-hundred and fourteen calves subjected to the stresses of marketing and shipping from Florida to New Mexico were used to study performance after arrival at the feedlot. Flaked milo diets containing 50 and 75% concentrates promoted more rapid recovery of purchase weight and more efficient gains than a diet containing 25% concentrates. Free-choice alfalfa hay with the flaked milo diets reduced death loss, number of calves requiring medication and number of treatments per medicated calf. A 3-day mass medication with oxytetracycline injected intramuscularly at 11 mg/kg body weight reduced death loss and number of calves requiring subsequent medication. Calves requiring subsequent medication, however, needed more treatments than control calves. Dry matter and energy digestion determined with Iambs increased with concentrate level but decreased with addition of alfalfa hay. Net energy intake was highest for the 50% concentrate diet during the first week and for the 75% concentrate diet during the next 3 weeks of the week receiving period. (Key Words: Beef Calves, Stressed Calves, Energy, Alfalfa Hay, Oxytetracycline.) Introduction Calves subjected to stresses of marketing and shipping have made more rapid gains with diets containing 70% or 72% concentrates than with diets containing higher or lower levels of concentrates (Koers et al., 1975; Lofgreen et al., 1975). In one trial with a 72% concentrate diet containing 49.5% rolled barley providing free access to alfalfa hay did not improve perfor- ~Journal article 723, Agr. Exp. Sta., New Mexico State Univ., Las Cruces Graduate assistant and assistant professor, Dept. of Anita. and Range Sci., Las Cruces mance of stressed calves (Lofgreen et al., 1975). Addis et al. (1975) showed that stressed calves fed a 72% concentrate diet containing flaked milo consumed less feed the first week after arrival than calves fed a similar diet containing rolled barley. Performance during a week receiving period, however, was not different between the two groups. Thus, calves consumed less of the milo diet during the first week but performed well the next 3 weeks. The effect of providing free choice hay with the milo diets was not studied. Addis et al. (1976) found that intramuscular administration of oxytetracycline for the first 3 days after arrival of stressed calves reduced the number of animals needing subsequent treatment. Oral administration of oxytetracycline, however, depressed feed intake and did not reduce sickness. The objectives of this study were to determine the effects of providing free-choice alfalfa hay with receiving diets containing different amounts of flaked milo, to investigate further the effect of intramuscular injection of oxytetracycline for 3 successive days after arrival of stressed calves and to relate digestibility to feed intake and performance during the 28-day receiving period. Experimental Procedures Five-hundred and fourteen (four loads) Good to Choice male stocker calves weighing approximately 160 kg were purchased from an order buyer in Florida and shipped by truck to Clayton, New Mexico. The time in transit varied from 39 to 46 hr, with no rest stop. The loads were received in October, December, January and February, so that some of the calves were subjected to cold weather stresses as well as stresses of gathering, transporting and processing. Calves were processed upon arrival, since this procedure was shown to be superior to delayed processing (Lofgreen et al., 1978). Pro- 590 JOURNAL OF ANIMAL SCIENCE, Vol. 50, No. 4, 1980

2 RECEIVING PROGRAMS FOR STRESSED CALVES 591 cessing consisted of weighing, castrating as necessary (32% bulls); vaccinating for infectious bovine rhinotracheitis (IBR), blackleg and malignant edema; branding; administration of a grubicide (13.2% Famophos); intramuscular injection of 500,000 IU of vitamin A; dehorning as necessary, and deworming with levamisol hydrochloride. In addition, each calf was eartagged, and rectal temperature was recorded. Those calves designated to receive the 3-day treatment of oxytetracycline were given intramuscular injections at a level of 11 mg/kg of body weight at the time of processing and for the next 2 days. Following processing, calves were assigned randomly to the treatments shown in table 1. Initially, calves having a rectal temperature of 39.4 C or above were considered sick and medication was initiated. The 158 calves diagnosed as sick on arrival were assigned randomly to treatments with all other calves. Since rectal temperatures increased with processing rime, the temperature at which calves were treated was increased to 40.0 C after approximately 1.5 hr and to 40.6 C after 3 hours. Calves with temperatures equal to or greater than the above levels were given an initial treatment of 11 mg/kg of oxytetracycline intramuscularly. If this treatment resulted in a lowered body temperature within 24 hr, it was continued for a total of 3 days. If the temperature was not lowered within 24 hr, treatment was changed. All calves were observed daily for visual signs of sickness, and each calf diagnosed as sick was treated for 3 successive days or for 1 day after return to normal body temperature, whichever was greater. Feed was provided twice daily in amounts sufficient to allow free-choice feed consumption. Composition of the diets is shown in table 2. The calves were weighed every 7 days for the first 4 weeks. After 4 weeks, the free-choice alfalfa hay was eliminated from the diet, and feeding was continued without hay for another 4 weeks. Diets consumed by the calves were evaluated by digestion trials with 24 wether lambs in a randomized block design consisting of four trials (blocks) with six lambs (diets) per trial. To simulate diets containing free-choice hay, alfalfa hay was coarsely ground and mixed with milled diets so that it comprised the same percentages of the total diets as the long-stem hay consumed by calves during the week feeding trials. Each animal was fed twice daily an amount slightly below its ad libitum intake, so that complete TABLE 1. DESIGN OF EXPERIMENT Load Free choice alfalfa hay Treatments Oxytetracycline preventive medication (No. of c~ves per pen) i0 I I I II -- I 0 11 II

3 592 LOFGREEN ET AL. TABLE 2. COMPOSITION OF DIETS Ingredient Internat'l Ref. No Ground alfalfa hay Cottonseed hulls Steam flaked milo 0444 Ground corn Rice bran Cottonseed meal Fat Molasses, cane 0696 Urea Limestone Sodium phosphate, monobasic Salt, trace mineralized Vitamin A Crude protein, % NE m, Meal per kg NEg, Meal per kg (%) ,200 IU per kg.5 (Estimated content) consumption of all diets was insured. This method resulted in feed intakes ranging from 900 to 1,200 g daily9 Preliminary feeding periods ranged from 17 to 20 days; collection periods were 7 days. During collection periods, feed and fecal samples were collected daily, and 10% fecal aliquots were immediately frozen. Aliquots from succeeding days were added to form composite samples for analysis. Nitrogen was determined prior to drying, and energy was determined on dry samples. Statistical analyses for all criteria were made by least-squares analysis of variance involving five factors (energy level, free-choice alfalfa hay, 3-day oxytetracycline treatment, loads and weeks). When treatment effects were indicated, means were compared by Duncan's multiple range test (Duncan, 1955). Results and Discussion Table 3 contains the F values for seven criteria of response to treatments. Although differences were observed among weeks and loads, the comparisons of primary interest are concentrate levels, addition of free-choice alfalfa hay, administration of oxytetracycline for the first 3 days and interactions of these three factors with each other and with weeks. Health and performance data for the first 28 days are shown in table 4. Because of greater energy density in the diet, calves fed the 75% concentrate diet consumed less feed than those fed the two lower levels. Not expected, however, was the greater consumption observed in calves on the 50% concentrate diet compared to those on the 25% level. Although differences were not statistically significant, the expected trend to lower feed requirements per unit of weight gain with increasing concentrates was observed. These findings with milo diets confirm those of Koers et al. (1975) and Lofgreen et al. (1975) that newly received calves respond well to diets containing up to 75% concentrates9 It is of interest to note the trend toward lower amounts of alfalfa hay consumed as concentrate level increased. One might expect the reverse because of the lower fiber levels in the higher concentrate diets. Apparently, the demand for readily available energy overrides any cravings for additional roughage. Moreover, adequate roughage may be supplied by the 75% concentrate diet. None of the differences in health criteria among concentrate levels was significant, although there was a trend toward increased numbers of calves treated and increased days treated as concentrate level increased. Similar trends have been noted in another study (Lofgreen, 1979). Consumption of an average of 1.76 kg of alfalfa hay over the week receiving period

4 RECEIVING PROGRAMS FOR STRESSED CALVES 593 TABLE 3. F VALUES FROM ANALYSES OF VARIANCE Criteria of response Feed Weight Gain per Death No. Days Comparisons intake gain kg feed loss treated treated Returns Concentrate level (Conc) 15.2"* 3.5* <1 <1 (All) 85.7** 14.4"* 9.9"* 4.8* 4.4 <1 <1 Oxytetracycline (Oxy) < * 30.0** 32.4** <1 Weeks (Wks) 576** 21.2"* 9.4"* 15.6"* a a 18.4"* Loads 23.4** 6.8** ** 48.8** * Interactions of interest Conc X alf < * 1.1 <1 <1 Conc X oxy 8.0** <1 <1 <1 Conc X wks <1 <1 <1 <1 a a <1 Alf X oxy <1 <1 <1 <1 < Alf wks ** 4.9* <1 a a <1 Oxy X wks 1.9 <1 <1 <1 a a 1.1 Means squares for error Degrees of freedom for error aweeks not included in the analysis of number and days treated. All except first three treatments occurred during the first week. *P<.05. **P<.Ot. resulted in lowered death loss, fewer calves returning for additional treatments after going through one series, a greater total feed consumption, a greater rate of gain, an improved feed conversion and a shorter period of time needed to regain weight lose during shipping. Lofgreen et al. (1975) reported no beneficial effects of free-choice alfalfa hay for newly TABLE 4. PERFORMANCE OF CALVES ON THREE CONCENTRATE LEVELS, WITH OR WITHOUT ALFALFA HAY AND WITH OR WITHOUT OXYTETRACYCLINE Oxytetracycline Free Three Item None choice None days No. of calves Death loss b 7 a 13 b 7 a No. treated d b 121 a 159 b 104a Days treated d No. of returns b 16 a 32 b 8 a Daily feed intake, kg a 1.76 b Milled diet b 2.77 a Totals 4.21 b 4.49 c 4.08 a 3.99 a 4.53 b Daily weight gain, kg.57 a.64 b.67 b.46 a.82 b.56 a 9 72b Feed per kg gain, kg b 5.52 a 7.63 b 5.90 a Days to regain shipping shrink b 22 a 36 b 26 a a'b'cvalues in appropriate comparisons having different superscripts are different (P<.05). dfor the oxytetracyctine group, only those calves requiring treatment following the 3 day mass treatment are included.

5 594 LOFGREEN ET AL. received calves fed diets containing barley in studies conducted in the Imperial Valley of California. Differences in dietary consumption and climatic conditions between the Imperial Valley and northeastern New Mexico could account for the differences in the effect of alfalfa hay between the two experiments. Interactions between alfalfa hay and weeks (table 3) are due to the effect of alfalfa hay on weight gain being significant only during the first 2 weeks and its effect on feed conversion is limited to the first week. The effect of alfalfa on death loss was significant on the 25% and 75% concentrate diets but not on 50% concentrates. The mass treatment of all calves with oxytetracycline for 3 successive days upon arrival resulted in reductions in death loss and in the number of calves requiring medication after treatment, an increase in rate of gain, an improvement in conversion of feed to gain and a reduction in time required to regain weight lost during shipping. Those calves in need of further medication after 3 days of oxytetracycline treatment took 2 days longer to return to normal than those requiring treatment from the control group. Apparently, calves that are still sick after the 3-day oxytetracycline treatment are more difficult cases and do not respond to medication as rapidly as calves not subjected to the treatment. Although there appeared to be no influence of oxytetracycline on feed intake, those calves fed the 25% concentrate and receiving the 3-day prevention medication program ate more feed than control calves. This difference was not observed in calves on the 50 and 75% concentrate diets. This observation accounts for the interaction of concentrate level and oxytetracycline shown in table 3. A comparison of the performance during the first 28 days, the second 28 days and for the entire 56 days is shown in table 5. The trends observed during the first 4 weeks are still evident in the comparison of concentrate levels, with an improved conversion of feed to gain as concentrate level increased. This improvement was to be expected once calves had recovered from stresses associated with marketing, transporting, receiving, et cetera. The important finding is that even when suffering from these stresses, the calves were able to utilize higher energy diets. Following removal of free-choice alfalfa from the diet after the first 28 days, calves that had received alfalfa hay gained less weight, and gain was less efficient during the next 28 days than for those that had had no hay during the first 4 weeks. Much of this effect was due to elimination of the differences in fill. Not all differences in performance were due to fill, however, since the weight gained over the TABLE 5. COMPARISON OF PERFORMANCE DURING SECOND 28 DAYS ON A COMMON DIET WITH THE FIRST 28 DAYS AND THE ENTIRE 56 DAYS Treatment during first 28 days Oxytetracycline -' Free Three Item None choice None days First 28 days: Daily feed intake, kg 4.21 b 4.49 c 4.08 a 3.99 a 4.53 b Daily weight gain, kg.57 a.64 b.67 b.46 a.82 b.56 a.72 b Feed per kg gain, kg b 5.52 a 7.63 b 5.90 a Second 28 days: Daily feed intake, kg 6.70 a 7.17b 6.57a Daily weight gain, kg Feed per kg gain, kg a Entire 56 days: Daily feed intake, kg 5.38 a 5.83 b 5.26 a 5.62 b 5.36 a... Daily weight gain, kg b.70 a.80 "173 Feed per kg gain, kg a 7.66 b a'b'cvalues in same row having different superscripts are different (P<.05).

6 RECEIVING PROGRAMS FOR STRESSED CALVES 595 TABLE 6. EFFECTS OF CONCENTRATE LEVEL AND FREE-CHOICE ALFALFA HAY ON DIGESTIBILITY Item None Free choice Dry matter digestion, % 60.9 a 63.6 b 69.5 c 65.3 b Energy digestion, % 58.2 a 64.0 b 69.7 c 65.8 b Crude protein digestion, % 68.9 a 71.6 b 72.0 b 69.5 a Digestible energy, Mcal/kg DM 2.56 a 2.72 b 2.96 c 2.79 b Digestible protein, % of DM 11.2 a 12.5 b 12.4 b 11.6 a 63.7 a 63.1 a 72.2 b 2.70 a 12.4 b a'b'cvalues in appropriate comparisons having different superscripts are different (P<.05). entire 8 weeks favored the calves fed alfalfa during the first 4 weeks. Weight gained over the entire 8 weeks was determined from the arrival and 8-week weights, neither of which would have been influenced by difference in fill due to hay consumption. Calves that had received the 3-day oxytetracycline treatment on arrival were fed along with control calves during the second 28 days, so no comparisons of this treatment could be made for feed consumption or feed conversion during the second 28-day period. The comparable weight gains, however, indicate that this treatment had no effect beyong those observed during the first 28 days. Effects of concentrate level and free-choice hay on digestible nutrient content and digestibility of diets are shown in table 6. Dry matter and energy digestion coefficients increased (P<.05) with increasing diet concentrate levels, but hay additions reduced (P<.05) dry matter and energy digestion coefficients of the diets. Increasing concentrate level from 25 to 50% iocreased crude protein digestion (P<.05), but increasing it from 50 to 75% resulted in no significant additional improvement. Hay additions increased apparent digestibility of dietary protein. Much of this increase might merely be due to the increase in total crude protein with the addition of hay. Such an increase would cause higher apparent digestibility even though true digestibility might be unaffected. Nutrient intake calculated from information obtained in the digestion trials applied to feed intake and weight gains observed in the feeding trials is presented in table 7. All diets appear to have been adequate in protein since the proteinto-energy ratios are well above those found adequate by Preston (1966). Apparent weight gains TABLE 7. NUTRIENT INTAKE AND ESTIMATION OF FILL Item 25 Free None choice Daily intake Feed, kg Digestible energy, Mcal (DE) Net energy for gain, Mcal (NEg) Digestible protein, kg (DP) DP/DE ratio, kg/kcal Apparent weight gain, kg a Expected weight gain, kg b Estimated fill, kg c Apparent gain due to fill, % auncorrected for death loss. bcalculated from NEg intake determined from digestion trials. r minus expected weight gain.

7 596 LOFGREEN ET AL. for the entire receiving period were correlated (r=.88, P<.05) with digestible energy (DE) intake; no significant correlation was observed between gains and protein intake. Because newly received calves are usually subjected to varying periods of starvation and are often dehydrated, weight gains observed during a 28-day receiving period would contain significant quantities of feed and water in contrast to actual tissue gain. It is possible to estimate the size of this fill by calculating the expected weight gain from net energy deposited in the weight gain (NEg). DE was converted to NEg by the method of Lofgreen and Garrett (1968). Metabolizable energy used in the conversion was calculated by multiplying DE by.82 (Maynard and Loosli, 1969). Feed used for maintenance was deducted from total intake to determine the portion remaining for gain. NEg values were then applied to this amount to determine the NEg deposited in weight gain, and the expected gain was determined from the equation developed by Lofgreen and Garrett (1968). Deduction of the expected weight gain from the apparent gain provided estimates of fill; these are shown in table 8. One half the apparent weight gain observed on the 25% concentrate diet consisted of fill; the apparent gains achieved by calves with access to alfalfa hay contained almost twice as much fill as those made by calves receiving milled diets only. Perhaps an estimate of NEg intake would be super- ior to apparent weight gains in evaluating receiving diets differing in roughage content. Literature Cited Addis, D. G., G. P. Lofgreen, J. G. Clark, J. R. Dunbar and C. Adams Barley vs milo in receiving rations. 14th Calif. Feeders Day Rep. 1975:53. Addis, D.G., G. P. Lofgreen, J. G. Clark, J. R. Dunbar, C. Adams and F. D. Cress Preventive medication for feedlot replacement calves. California Agr. 30:18. Duncan, D. B Multiple range and multiple F tests. Biometrics 11 : 1. Koers, Walter C., J. C. Parrott, II1, L. B. Sherrod, R. H. Klett and W. G. Sheldon Receiving and sick pen rations for stressed calves. J. Anim. Sci. 41:40 (Abstr.). Lofgreen, G. P Further studies with newly received calves. Proc. Livestock Res. and Cattle Growers Short Course. New Mexico State Univ., p. 33. Lofgreen, G. P., D. G. Addis, J. R. Dunbar and J. G. Clark Time of processing calves subjected to marketing and shipping stress. J. Anim. Sci. 45:1324. Lofgreen, G. P., J. R. Dunbar, D. G. Addis and J. G. Clark Energy level in starting rations for calves subjected to marketing and shipping stress. J. Anim. Sci. 41:1256. Lofgreen, G. P. and W. N. Garrett A system for expressing net energy requirements and feed values for growing and finishing beef cattle. J. Anim. Sci. 27:793. Maynard, L. A. and J. K. Loosli Animal Nutrition (6th Ed.). McGraw-Hill Book Co., New York. Preston, R. L Protein requirements of growingfinishing cattle and lambs. J. Nutr. 90:157.