Calf management before transport influences later performance under stress, Canadian researchers say.
Behavioral and physiological indicators of stress, as well as growth performance and morbidity rates, were assessed in 174 steer calves (480 lbs. ± 81.5 lbs.) for 30 days after transport from ranch to feedlot.
The calves were conditioned (C) or not (NC), and subjected to either short (2.7 hours, SH) or long hauls (15 hours, LH). Calves in the study were weaned and vaccinated 13 and 29 days, respectively, prior to transport, and therefore defined as conditioned. All calves in the study were dehorned and castrated 10-14 days after birth.
Upon arrival at the feedlot, calves were randomly assigned to 16 pens, four pens/treatment, one of which was equipped with a radio-frequency ID system for continual monitoring of individual bunk attendance. As part of the NC treatment, calves were also exposed to a short (2-hour) transport 24 hours after their initial arrival to the feedlot. All calves were fed a barley silage/barley grain-based starter ration and weighed every seven days.
Cortisol concentrations were higher in NC compared to C calves regardless of transport distance. NC calves also had higher pre- and post-loading cortisol concentrations than C calves. In transit, CSH steers had the lowest heart rate (67.8 beats/minute). Heart rate was highest during the first 15 minutes of the journey for all calves and gradually declined until 121-161 minutes into the trip. NC calves spent more time at the feed bunk than C calves (222.9 minutes/day vs. 128.6 minutes/day) in the first two days in the feedlot. CLH calves were observed more frequently at the water than NCLH calves.
An interaction was observed for shrinkage and average daily gain (ADG). Shrinkage was greater in CLH than in NCLH steers (52 lbs. vs. 32.2 lbs.), and in NCLH than in either CSH (17.2 lbs.) or NCSH (20.3 lbs.) steers. The lowest ADG was recorded for CLH and NCSH calves (1.76 lbs. and 1.98 lbs., respectively), although their dry matter intake (13.2 lbs./day vs. 15 lbs./day) was similar to calves in the other treatment groups. Morbidity rate was 5.17% with no treatment effect.
The study shows conditioning calves prior to transport allowed them to better tolerate the stressors of transport and handling. This was observed in lower cortisol concentrations pre- and post-loading, as well as higher percentages of time feeding and less time standing and milling in their pens immediately after transport compared to NC calves. In addition, the combined effect of conditioning and short-haul transport was least stressful as witnessed by the low shrink, high dry matter intake and ADG in the first month after transport.
— Schwartzkopf-Genswein, et al, 2007, Applied Animal Behavior Science, 108.
Combining parasite products decreases parasite burden and improves feedlot performance compared to a single approach, Kansas State University researchers say.
Two studies utilizing 1,862 yearling heifers were conducted to determine the effects of a fenbendazole oral drench in addition to an ivermectin pour-on (SG+IVPO), compared to an invermectin pour-on (IVPO) or a doramectin injectable alone (DMX) on parasite burden, feedlot performance and carcass merit of feedlot cattle.
In the first study, heifers receiving the SG+IVPO had fewer cattle retreated for disease and 73% fewer worm eggs/fecal sample 98 days after treatment than heifers treated with IVPO. Heifers treated with SG+IVPO consumed more dry matter (DM), had greater ADG, were heavier at slaughter and had heavier carcasses than IVPO-treated heifers. Heifers treated with SG+IVPO also had more carcasses grading USDA Prime or Choice than IVPO-treated heifers.
In the second study, heifers treated with SG+IVPO had fewer worms/fecal sample 35 days after treatment and had fewer numbers of adult and larval Cooperia and Trichostrongylus spp. in the small intestine at slaughter compared to heifers treated with DMX. Heifers treated with SG+IVPO consumed more DM, were heavier at slaughter and had heavier carcasses than DMX-treated heifers. The SG+IVPO-treated heifers also had greater ADG.
Researchers summarized that the broad-spectrum effectiveness of a combination of a fenbendazole oral drench and an ivermectin pour-on reduced parasite burden and increased feed intake, ADG and carcass weight in feedlot heifers compared with treatment with an endectocide alone.
— C.D. Reinhardt, et al, 2006, Journal of Animal Science, 84:2243.
Ticks can survive being put through the washing machine, a USDA Agricultural Research Service entomologist says.
When he found a live lone star tick (Amblyomma americanum) on the agitator of his washing machine, the researcher decided to find out how tough ticks are. He bagged up nymphs from two species — the lone star tick and the deer tick (Ixodes scapularis) — and put them in the washing machine.
Ticks were placed in mesh bags, which kept them from draining away during the rinse cycle.
A combination of water-temperature settings and detergent types were used to wash ticks. The majority of lone star ticks survived all the water-detergent combinations with no obvious side effects. Most of the deer ticks lived through the cold- and warm-water settings as well. But when one type of detergent was used with a hot-water setting, only 25% of the deer ticks survived.
The entomologist also tested tick hardiness in a dryer setting. All of the ticks of both species died after an hour of tumbling around at high heat. But when the dryer was set to “no heat,” about one-third of the deer ticks and more than half of the lone star ticks survived.
The researcher noted that ticks might survive a sudsy interlude by sheltering in the folds and crevices of a typical load of laundry. Some ticks have been observed to survive hours of submersion in fresh water.
This research reinforces recommendations by the U.S. Centers for Disease Control and Prevention to wash and dry clothes at high temperatures after spending time in areas known to harbor ticks.
— ARS Research Report, October 2007
The method of delivering supplements to steers on wheat pasture isn't that important, Oklahoma State University researchers say.
A two-year study, 2004-05 (YR1) and 2005-06 (YR2) was conducted during winter wheat-grazing seasons to determine the effects of supplementation strategies and delivery methods on supplement intake and growth performance of grazing steers. The first year consisted of 253 steers whose initial body weight was 562 ± 55 lbs.; the second year consisted of 116 steers weighing 633 ± 31 lbs.
Five treatments were as follows:
Negative control (NC), no supplemental nutrients;
free-choice, non-medicated mineral (MIN);
free-choice, medicated mineral with 1,785 mg of monensin/kg of mineral mixture (RMIN);
RMIN and soybean hull (SH-RMIN); and
a soybean hull-based energy supplement containing 165 mg of monensin/kg (GRNGOLD).
Energy supplements were hand fed on alternate days (average daily intake = 2 lbs./steer).
Inclusion of monensin in the free-choice mineral mixture decreased intake of the mineral mixture by 63% in YR1 and 55% in YR2 when no other supplement was offered. Consumption of RMIN provided from 129 to 161 mg of monensin/steer, whereas GRNGOLD provided 150 mg of monensin/day.
Compared with NC, MIN did not affect ADG in YR1, but increased ADG by 0.485 lbs./steer in YR2. Conversely, ADG of RMIN steers was greater than that of MIN steers during YR1 (1.59 lbs. vs. 1.21 lbs./steer) but not different in YR2.
Providing supplemental energy increased ADG by 0.286 lbs./steer in YR1 compared with RMIN, but no increase in ADG was observed in YR2. No difference was observed in ADG between SH-RMIN and GRNGOLD in either year.
Conversion of the energy supplements (lb. of as-fed supplement divided by lb. of additional ADG) was excellent in YR1, resulting in 2.2 lbs. of bodyweight gain for each 6.8 lbs. of supplement consumed. However, due to smaller increases in ADG with the energy and monensin supplements in YR2, supplement conversion for YR2 averaged 17.6.
Researchers conclude that the lack of difference in ADG between steers that received SH-RMIN and GRNGOLD suggests that the method of delivery (separate packages vs. a single package) for energy, monensin and mineral supplementation isn't important.
— B.G. Fieser, et al, 2007, Journal of Animal Science, 85:3470.