F.L. Fluharty, S.C. Loerch, and F.E. Smith
Department of Animal Sciences
Six mature Simmental x Angus cows that were determined to be non-pregnant and six Simmental x Angus steer calves were used as trainer animals in a completely randomized design experiment to determine the effectiveness of trainer animals on the performance and behavior of newly weaned calves after arrival at the feedlot. The trainer cows gained 135 pounds, and the trainer steers gained 109 pounds during their 5 weeks in the feedlot. On day 1, more (P < 0.05) calves in the trainer cow group (81.7%) were observed eating compared with either the steer trainer group (60%) or the control group containing no trainer animal (48.3%). Furthermore, newly arrived calves in both the cow and steer trainer groups came to the bunk more frequently (P < 0.05) compared with the control group (1.4 and 1.5 vs 0.9, respectively). On day 2, more (P < 0.05) calves were observed eating in both the cow and steer trainer groups compared with the control group (68.3% and 63.3% vs 38.3%, respectively). From days 3 to 7, there no longer were any differences (P > 0.10) in the percentage of calves eating between the cow trainer group and the control group. Calves with trainers tended to gain faster (2.5 and 2.4 pounds/day) than calves without trainers (1.5 pounds/day) during week 1. There were no differences in the final weights of the calves (day 28 after arrival) due to the presence of trainer animals. Additionally, the overall average daily gain (ADG) was nearly identical for all groups. Calves without trainers compensated for any decrease in ADG early in the receiving period by having an increased ADG in subsequent weeks.
Newly weaned calves undergo a period of depressed feed intake during the first 2 weeks following feedlot arrival (Cole and Hutcheson, 1988; Fluharty et al., 1994b). This depression in feed intake occurs at the same time that the calves need to mount an immune response to several pathogenic organisms, as well as vaccines given at the time of arrival. Recent research has shown that the reduction in dry matter intake (DMI) normally associated with newly arrived feedlot calves is not due to a reduction in the digestive capability of the ruminal microbial population (Fluharty et al., 1994a; Fluharty et al., 1996). Additionally, receiving diets formulated to contain a high concentration of dietary crude protein (CP) resulted in an increase in performance compared with diets formulated to be between 11 to 12% CP (Fluharty and Loerch, 1995). However, the diets containing a high concentration of CP were considerably more expensive than those containing 11 to 12% CP. Furthermore, increasing the CP concentration of receiving diets does very little to benefit those calves that consume very little or no feed. The best solution to the problem obviously would be to find a way to make all the calves consume the receiving diet at a normal level of intake consistent with their body weight.
Prior to weaning, calves are reared in an hierarchical society, with the brood cow being the dominant figure. The cow teaches her calf how to eat, where to find water, and serves as a protector. When newly weaned calves are grouped together in a feedlot, they are placed in a new environment where both the feed and water sources are foreign, and the social hierarchy is destroyed. In Ohio, there is an abundant supply of cows in the fall that have not rebred. These cows normally are somewhat thin and are relatively inexpensive due to their lack of condition. These non-pregnant cows may be an ideal trainer animal for newly weaned feedlot calves, because they could potentially show the calves how to eat from a feed bunk and drink from a waterer. Furthermore, due to their thin condition, efficiency of gain may be excellent for these animals when given a feedlot receiving diet. The objectives of this experiment were 1) to determine the effects of using either open cows or previously feed-bunk adapted calves as trainer animals for newly weaned feedlot calves, and 2) to determine the effects and economic possibilities of using a short-term feeding program for open cows prior to marketing them for slaughter.
Six mature Simmental x Angus cows that were determined to be non-pregnant and six Simmental x Angus steer calves were used as trainer animals in a completely randomized design experiment to determine the effectiveness of trainer animals on newly weaned calves after arrival at the feedlot. The experiment was initiated in October and had a duration of 28 days. The trainer animals were housed individually in pens (18 x 18 feet) constructed with metal gates and cables, slatted concrete floors, concrete feed bunks, automatic waterers, and located in an open-sided barn. The trainer animals were allowed a 3- week pen and diet adaptation period. During the adaptation period, the trainer animals were fed a feedlot receiving diet formulated to contain 70% concentrate and 30% forage, with a protein concentration of 16% (Table 1). Daily DMI was determined on each individual animal during week 3 of the adaptation period.
| Table 1. Diet composition. | |
|---|---|
| Item | %, Dry matter basis |
| Ingredient | |
| Shelled corn | 20.00 |
| Corn silage | 60.00 |
| Ground corn | 0.84 |
| Soybean meal | 15.85 |
| Urea | 0.40 |
| Limestone | 0.90 |
| Dicalcium phosphate | 0.59 |
| Trace mineral salt1 | 0.50 |
| Vitamin A (30,000 IU/g) | 0.01 |
| Vitamin D (3,000 IU/g) | 0.01 |
| Selenium (201 mg Se/kg) | 0.05 |
| Aureomycin-S 700 | 0.10 |
| Potassium chloride | 0.35 |
| Dynamate2 | 0.40 |
| Calculated composition | |
| Crude protein, % | 16.00 |
| Calcium, % | 0.63 |
| Phosphorus, % | 0.43 |
| Potassium, % | 1.24 |
| NEm, Mcal/kg | 1.77 |
| NEg, Mcal/kg | 1.16 |
| 1 Contained: > 93% NaCl, 0.35% Zn, 0.28% Mn,
0.175% Fe, 0.035% Cu, 0.007% I, and 0.007% Co.
2 Magnesium sulfate and potassium sulfate. Contained: > 22% S, 18% K, and 11% Mg (International Minerals and Chemical, Terre Haute, IN). | |
After the trainer animals had been given 3 weeks of diet adaptation, 180 newly weaned Simmental x Angus crossbred steer calves purchased in Dublin, Virginia, and transported approximately 500 miles by truck to Wooster, Ohio, were allotted by weight to 18 pens, each containing 10 steers. The three experimental treatments were 1) one trainer cow per pen, 2) one trainer steer calf per pen, or 3) no trainer animal in the pen. Therefore, six of the pens contained one previously adapted cow, six of the pens contained one previously adapted steer calf, and six of the pens contained no trainer animals. Calves in the pens containing no trainer animals were housed so that they were out of sight of animals in the other treatment groups.
All pens of cattle were fed once daily, commencing at 0800 hours. On a daily basis, feed refusal was weighed, recorded, and discarded so that ad libitum feed intake for each pen could be determined. Feed intake was determined for each individual trainer animal based on the average daily intake during week 3 of the adaptation period, and the feed intake subtracted from the amount recorded as consumed by the newly arrived steers. On days 7, 14, 21, and 28, all steers were weighed before feeding (starting at 0800 hours) to determine weekly performance. Initial and final weights were determined by using the average of two consecutive days. The ADG and dry matter intake (DMI) were determined for each weekly period. Additionally, daily DMI was calculated for the first 14 days of the experiment to determine the effects of trainer animals on DMI of newly arrived feedlot calves. On day 15, all trainer animals were removed from the pens prior to feeding to determine if the newly arrived calves would continue to consume feed at the same level once the trainer animal had been removed from the pen.
On the first 7 days following feedlot arrival, calves were observed to determine the number of calves coming to the feed bunk and the number of times that an animal came to the bunk during the first half-hour after feeding.
The performance of the trainer cows and steers is shown in Table 2. The trainer cows gained 135 pounds, and the trainer steers gained 109 pounds during their 5 weeks in the feedlot (3.8 and 3.0 pounds/day, respectively). However, during the first 7 days after arrival of the newly weaned calves, the cows lost 24 pounds, and the steers lost 13 pounds. There was a great deal of activity during the first week following arrival of the newly weaned calves as the trainer animals became adjusted to the newly arrived calves. This weight loss indicates that intake of trainer animals was decreased due to introduction of the newly weaned calves. Attempts to estimate DMI of just the newly arrived calves was problematic, because no good measurement of trainer animal DMI could be made.
| Table 2. Performance of trainer cows and steers. | |||
|---|---|---|---|
| Dates | Cows | Steers | |
| Initial weight, pounds | 09/13/95 | 1196 | 543 |
| On-test weight, pounds | 10/05/95 | 1285 | 631 |
| Off-test weight, pounds | 10/10/95 | 1331 | 652 |
| Gain, pounds | 135 | 109 | |
| ADG1, pounds/day | 3.8 | 3.0 | |
| DMI2, 7 days prior to going on test, pounds/day | 39.0 | 18.7 | |
| Weight on day 7, pounds | 10/12/95 | 1261 | 618 |
| 1 ADG = Average daily gain.
2 DMI = Dry matter intake. | |||
| Table 3. Effects of trainer animals on eating behavior of newly weaned beef calves. | ||||
|---|---|---|---|---|
| Trainer animal group | ||||
| Item | Cow | Steer | None | SEM1 |
| Day 1 | ||||
| % Eating | 81.7a | 60.0b | 48.3b | 6.4 |
| Number of meals | 1.4a | 1.5a | 0.9b | 0.2 |
| Day 2 | ||||
| % Eating | 68.3a | 63.3a | 38.3b | 8.8 |
| Number of meals | 1.0 | 1.0 | 0.7 | 0.2 |
| Day 3 | ||||
| % Eating | 56.7 | 53.3 | 50.0 | 8.3 |
| Number of meals | 0.9 | 0.8 | 0.7 | 0.1 |
| Day 4 | ||||
| % Eating | 80.0a | 53.3b | 71.7a | 7.2 |
| Number of meals | 1.2a | 0.6b | 1.0a | 0.1 |
| Day 5 | ||||
| % Eating | 80.0 | 71.7 | 65.0 | 5.4 |
| Number of meals | 0.9 | 0.9 | 0.9 | 0.1 |
| Day 6 | ||||
| % Eating | 93.3a | 73.3b | 88.3a | 4.1 |
| Number of meals | 1.1 | 1.0 | 1.1 | 0.1 |
| Day 7 | ||||
| % Eating | 91.7 | 85.0 | 83.3 | 4.2 |
| Number of meals | 1.4a | 1.2a | 0.9b | 0.1 |
| 1 SEM - standard error of mean.
ab Means in a row with different superscripts differ (P < 0.05). | ||||
The effects of trainer animals on eating behavior of newly weaned calves are shown in Table 3. On day 1, more (P < 0.05) calves in the trainer cow group (81.7%) were observed eating compared with either the steer trainer group (60%) or the control group containing no trainer animal (48.3%). Furthermore, newly arrived calves in both the cow and steer trainer groups consumed more meals (P < 0.05) compared with the control group (1.4 and 1.5 vs 0.9, respectively). On day 2, more (P < 0.05) calves were observed eating in both the cow and steer trainer groups compared with the control group (68.3% and 63.3% vs 38.3%, respectively). From days 3 to 7, there were no longer any differences (P > 0.10) in the percentage of calves eating between the cow trainer group and the control group. On days 4 and 6, fewer (P < 0.05) calves in the steer trainer group were observed eating compared with the cow trainer group. Although not always significant, the cow trainer group had the numerically greatest percentage of calves observed eating on all days.
The effects of trainer animals on performance of newly weaned calves is shown in Table 4. There were no differences (P > 0.10) in final weight due to the presence of trainer animals. Additionally, the overall ADG was nearly identical for all groups. During week 1, there was a trend (P < 0.10) for calves in the cow trainer group to have an increased ADG compared with calves in the control group. However, during week 2, the control group had the greatest (P < 0.05) ADG. Therefore, calves compensated for any decrease in ADG early in the receiving period by having an increased ADG in subsequent weeks. There were no differences (P > 0.10) in morbidity due to trainer animals. However, from a numerical standpoint, the greatest percentage of calves became sick in the pens containing trainer steers. This probably occurred because 4 out of the 6 trainer steers themselves became sick following introduction of the newly weaned calves. Most health and intake problems occurred in the first 2 weeks after feedlot arrival. This report suggests that use of trainer cows may have potential to reduce these problems.
| Table 4. Effects of trainer animals on performance of newly weaned beef calves. | ||||
|---|---|---|---|---|
| Trainer animal group | ||||
| Item | Cow | Steer | None | SEM1 |
| Number of steers | 60 | 60 | 60 | |
| Initial weight, pounds | 528.7 | 527.6 | 529.0 | 0.97 |
| Final weight, pounds | 616.4 | 614.6 | 616.3 | 4.25 |
| Average daily gain, pounds/day | ||||
| Week 1 | 2.51 | 2.42 | 1.48 | 0.50 |
| Week 2 | 4.37a | 3.77a | 5.56b | 0.39 |
| Week 3 | 4.08 | 3.96 | 3.68 | 0.47 |
| Week 4 | 1.57 | 2.28 | 1.75 | 0.30 |
| Overall | 3.13 | 3.11 | 3.12 | 0.14 |
| Morbidity, % | 8.3 | 28.3 | 16.7 | 8.0 |
| 1 SEM = standard error of mean.
ab Means in the same row without a common letter in their superscript differ (P < 0.05). | ||||
The authors wish to thank Johanna Calgie, Shereen Hejazi, and Heather Young for their assistance in observation of the cattle.
Cole, N.A., and D.P. Hutcheson. 1988. Influence of protein concentration in prefast and postfast diets on feed intake of steers and nitrogen and phosphorus metabolism of lambs. J. Anim. Sci. 66:1764.
Fluharty, F.L., and S.C. Loerch. 1995. Effects of protein concentration and protein source on performance of newly arrived feedlot steers. J. Anim. Sci. 73:1585.
Fluharty, F.L., S.C. Loerch, and B.A. Dehority. 1994a. Ruminal characteristics, microbial populations, and digestive capabilities of newly weaned, stressed calves. J. Anim. Sci. 72:2969.
Fluharty, F.L., S.C. Loerch, and B.A. Dehority. 1996. Effects of feed and water deprivation on ruminal characteristics and microbial population of newly weaned and feedlot-adapted calves. J. Anim. Sci. 74:465.
Fluharty, F.L., S.C. Loerch, and F.E. Smith. 1994b. Effects of energy density and protein source on diet digestibility and performance of calves after arrival at the feedlot. J. Anim. Sci. 72:1616.
NRC. 1984. Nutrient Requirements of Beef Cattle (6th. Ed.). National Academy Press, Washington, DC.