ABSTRACT
Two experiments were conducted to determine the effects of feeder design on hay intake, apparent diet digestibility, and hay waste in gestating beef cows. Native tallgrass prairie hay and a protein supplement was fed throughout both experiments. In Exp. 1, 56 crossbred cows were used in a Latin square arrangement. Feeder design treatments included a conventional open bottom steel ring (OBSR), an open bottom polyethylene pipe ring (POLY); a sheeted bottom steel ring (RING), and a sheeted bottom steel ring with a basket (BASK). Cows were weighed and allotted based on BW to one of four previously grazed 2.0 ha paddocks equipped with a concrete feeding pad. Fourteen cows were assigned to each paddock and three round bales were fed consecutively within each treatment period. The cows acclimated to the feeders while the first bale was being consumed. Subsequently, hay waste data were collected while the second and third bale within each period were being consumed. Waste was measured for each bale at 24, 48, 72, and 96 h after each bale was introduced into the pen. Hay waste was significantly affected by hay feeder design with 19.7, 21.1, 12.4, and 5.5% of original bale weight wasted for OBSR, POLY, RING, and BASK, respectively (P < 0.01). There was a feeder design × day interaction (P < 0.01) with greater waste when the bale was first introduced into the pen in OBSR, POLY, and RING feeders and gradually declining thereafter, while waste from the BASK feeder was consistently low. There was a tendency (P = 0.06) for cows eating from OBSR feeders to consume less hay than cows eating from RING feeders. Feeder design did not influence apparent diet digestibility (P = 0.46). In Exp. 2, 64 crossbred cows (body weight = 590 ± 59 kg) were used to determine waste, forage intake, and apparent diet digestibility when hay was fed from a sheeted bottom steel ring (RING) or a RING feeder with a cone insert (CONE). More hay was wasted when cows were fed from RING feeders compared to CONE feeders (11.9% vs. 4.8%, P < 0.01). Feeder design had no effect on DMI or apparent digestibility (P > 0.45). Hay savings from adopting a more conservative feeder design can have a dramatic influence on hay utilization by beef cows and thus on cost of production.
ABSTRACT
Feedgrade chlortetracycline (CTC) and oxytetracycline (OTC) are approved for use in beef cattle diets for the control of bovine respiratory disease (BRD). The objectives of this experiment were to compare CTC and OTC, administered according to label, for the treatment of BRD in Holstein calves and to characterize the influence of tulathromycin metaphylaxis in combination with tetracycline treatment. Summer-placed Holstein steer calves (n = 6,800) were randomly assigned to one of four treatments (11 blocks; initial BW = 140 ± 18 kg) as they passed through the squeeze chute at initial processing in a commercial feedlot. Treatments consisted of: (i) CTC and tulathromycin metaphylaxis (CTC+TUL), (ii) OTC and tulathromycin metaphylaxis (OTC+TUL), (iii) tulathromycin metaphylaxis only (TUL), or (iv) CTC only (CTC). Cattle were fed for an average of 118 d. Tetracycline feeding was instituted based on visual assessment of the attending veterinarian in accordance with the veterinary feed directive. When applicable, CTC was fed as a top-dress at a rate of 4 g CTC·steer-1·d-1 for 5 consecutive days, beginning on 6 d on feed (DOF). Three 5-d pulses were delivered to CTC+TUL and CTC cattle, with a 48-h time lapse between pulses. Cattle on OTC+TUL were administered 4 g OTC·steer-1·d-1 as part of a complete diet for 14 consecutive days beginning on 10 DOF. Within the first 30 d of the feeding period, BRD first pulls were reduced (P = 0.001) for CTC+TUL, OTC+TUL, and TUL relative to CTC alone. Percentage of BRD first pulls and total morbidity were lowest (P = 0.001) for CTC+TUL across the feeding period, with OTC+TUL and TUL being intermediate, and CTC alone exhibiting the highest percentage. Death loss and railers were not influenced (P ≥ 0.58) by treatment. Dry matter intake was greater (P = 0.001) for CTC+TUL than all other treatments. Final BW and ADG were greatest for CTC+TUL, lowest for TUL alone, and intermediate for the remaining treatments (P < 0.05) on a deads-and-railers-out basis. Deads-and-railers-in ADG was greatest (P < 0.05) for CTC+TUL compared to all other treatments. Feed conversion was not influenced (P ≥ 0.22) by treatment. In the current study, supplementation of OTC in combination with tulathromycin metaphylaxis did not benefit health over tulathromycin alone. Results suggest that CTC in combination with tulathromycin metaphylaxis reduces morbidity in Holstein steers calves, which may lead to improved performance.
ABSTRACT
Holstein beef has become a significant segment of the feedlot industry. Holstein steers typically enter the feedlot at a lighter body weight, require more pen space per animal, and are in the feedlot for longer periods of time than beef breeds. The only real differences in carcass characteristics are the lower dressing percentage and the smaller rib eye area, which can be increased with anabolic implants and the use of beta-agonists. Holsteins are typically fed higher roughage concentrations. Fat concentrations can also be increased to offset the lower energy diets. Protein requirements do not appear to be different from beef cattle, although Holstein steers weighing from 300 to 700 lb should be fed plant protein sources (eg, soybean meal).
