Short communication: administering an appeasing substance to Bos indicus-influenced beef cattle at weaning and feedlot entry.

The bovine appeasing substance (BAS) is expected to have calming effects in cattle experiencing stressful situations. Therefore, this study investigated the impacts of BAS administration during two of the most stressful events within beef production systems: weaning and feedlot entry. In experiment 1, 186 Bos indicus-influenced calves (73 heifers, 113 bulls) were weaned at 211 ± 1 days of age (day 0). At weaning, calves were ranked by sex and BW, and assigned to receive BAS (Nutricorp, Araras, SP, Brazil; n = 94) or water (CON; n = 92). Treatments (5 ml) were topically applied to the nuchal skin area of each animal. Calf BW was recorded and samples of blood and tail-switch hair were collected on days 0, 15 and 45. Calves that received BAS had greater (P < 0.01) BW gain from day 0 to 15 compared with CON. Overall BW gain (days 0 to 45) and BW on days 15 and 45 were also greater (P ≤ 0.03) in BAS v. CON. Plasma haptoglobin concentration was less (P < 0.01) in BAS v. CON on day 15, whereas cortisol concentrations in plasma and tail-switch hair did not differ between treatments (P ≥ 0.13). In experiment 2, 140 B. indicus-influenced bulls (∼27 months of age) from 2 different pasture-based systems (70 bulls/origin) were transported to a commercial feedlot (≤ 200-km transport; day -1). On day 0, bulls were ranked by source and BW, and assigned to receive BAS (n = 70) or CON (n = 70) and the same sampling procedures as in experiment 1. Bulls receiving BAS had greater (P = 0.04) BW gain from day 0 to 15, but less (P < 0.01) BW gain from day 15 to 45 compared to CON. No other treatment effects were detected (P > 0.14). Therefore, BAS administration to beef calves alleviated the haptoglobin response associated with weaning, and improved calf growth during the subsequent 45 days. Administration of BAS to beef bulls at feedlot entry improved BW gain during the initial 15 days, but these benefits were not sustained throughout the 45-day experiment.

Impact of 24-h feed or water, or both, deprivation on feed intake, metabolic, and inflammatory response in beef heifers.

This experiment evaluated the effects of 24-h feed or water, or both, restriction on hay intake, metabolic, and inflammatory response in growing beef heifers. Forty Angus × Hereford heifers were ranked by initial body weight (BW) (275 ± 6 kg) and age (278 ± 6 d) and randomly allocated to 20 drylot pens (two heifers per pen) in 5, consecutively run, 4 × 4 Latin squares containing four periods of 17 d each. From days 5 to 0 of each period, all pens were offered alfalfa-grass hay ad libitum plus 454 g of dried distillers' grains with solubles (as-fed basis) per heifer/d. On day 0 of each period, pens received one of the four treatments: 1) feed and water restriction for 24 h (FWR), 2) feed restriction for 24 h (FR), 3) water restriction for 24 h (WR), or 4) full access to feed and water (CON). Treatments were concurrently applied from days 0 to 1. Heifer full BW was collected for two consecutive days (days 6 and 5), before (day 0) and after (day 1) treatment application, and on days 3, 6, and 10 of each period. Hay dry matter intake was recorded daily from days 5 to 10. Blood was collected on days 5, 0, 1, 3, 6, and 10 of each experimental period. Following treatment on day 1, BW loss was greater, and heifer BW was less (P < 0.01), for WR, FWR, and FR compared with CON, whereas similar (P > 0.13) for BW loss and heifer BW among heifers that received nutrient restriction. No treatment effects were detected (P = 0.88) for overall ADG. Plasma cortisol concentration was greater (P < 0.01) in FR and FWR vs. WR and CON on day 1, and similar (P = 0.46) between CON and WR. Serum NEFA concentration was greater (P < 0.01) in FR and FWR vs. WR and CON on day 1, and also greater (P < 0.01) in WR vs. CON heifers on day 1. No treatment effects were detected (P = 0.53) for plasma haptoglobin concentration. Hence, feed or water, or both, restriction for 24 h did not affect hay intake and ADG, whereas metabolic results suggest that nutrient deprivation is the major contributor to the increased cortisol and NEFA response of growing beef heifers.