Effects of an Appeasing Substance Application at Weaning on Growth, Stress, Behavior, and Response to Vaccination of Bos indicus Calves.

An analog of a bovine-appeasing substance (BAS) was previously demonstrated to have calming effects, and it could be an alternative to alleviate the stress caused by weaning. Thus, the objective of this study was to evaluate the effects of BAS administration at weaning on growth, stress, behavior, and response to vaccination of Nellore calves. Eighty-six Nellore calves (40 females and 46 males) were abruptly weaned and randomly assigned into 1 of 2 treatments: (1) saline solution (0.9% NaCl; n = 43) and (2) BAS (Secure Catte, IRSEA Group, Quartier Salignan, France; n = 43). The solutions were topically applied (5 mL/calf) to the nuchal skin area of each animal. On d 0, before treatment application, calves were vaccinated against infectious bovine rhinotracheitis (IBR), parainfluenza-3 (PI3) virus, and bovine viral diarrhea virus types 1 and 2 (BVDV-1 and 2). Calves from each treatment were kept in different pastures for 15 d (time of BAS action) and then moved to a single pasture. Body weight (BW), blood samples, and temperament in the chute (entry score, chute score, and exit score) were collected on d 0, 3, 8, 15, 51, and 100, and behavior on pasture on d 1, 2, 4, 5, 6, 7, and 9. Calves assigned to BAS vs. Saline treatment tended to have greater BW on d 15 (p = 0.10), tended to have lower entry scores on d 8 and 51 (p = 0.10), and chute scores on d 8 (p = 0.07), and had lower exit scores on d 8 (p = 0.02). Calves assigned to BAS vs. Saline treatment also had greater time grazing on d 7 and 9 (p < 0.01), eating concentrate on d 2, 5, and 6 (p = 0.05), walking on d 1, 2, 5, and 9 (p < 0.01), standing and ruminating on d 2, 7 and 9 (p < 0.01), and playing on d 2, 4, 6, 7, and 9 (p < 0.01). Furthermore, they had lower time lying on 1 and 2 (p < 0.01), standing on d 5 and 9 (p < 0.01), and vocalizing on d 1 and 2 (p < 0.01). Calves assigned to BAS vs. Saline treatment had greater serum titter concentrations of PI3 t on d 15 and 51 (p = 0.05) and BVDV-1 on d 51 (p = 0.02). However, they had lower serum concentrations of cortisol on d 3 (p = 0.03). BAS administration did not affect (p ≥ 0.12) the serum titer concentration of IBR and BVDV-2 titers or the plasma concentration of haptoglobin and ceruloplasmin. The BAS administration improved BW, reduced temperament and serum cortisol concentration, and improved behavior and response to vaccination.

Effect of injectable trace mineral at weaning on growth and physiology of Nellore calves under feed restriction.

Calves are susceptible to a wide variety of stressors besides the seasoning low forage availability during their weaning phase. Thus, it is ideal if they receive adequate trace mineral supplementation during this period. This study evaluated the effect of injectable trace minerals (ITM) on performance, concentration of oxidative stress enzymes, and biochemical plasmatic parameters in Nellore calves during the weaning phase and under feed restriction. A total of 30 Nellore calves were used at the age of 7 ± 1 month and 176.23 ± 21.68 kg of initial body weight (BW). These animals were allocated in Urochloa decumbens pasture for 28 days and transferred to Urochloa brizantha cv Marandu pasture for another 28 days. The treatments were: Saline (saline solution; 0.9% NaCl) and ITM (Multimin®, providing: 15 mg Cu/mL, 60 mg Zn/mL, 10 mg Mn/mL, and 5 mg Se/mL). Both treatments were applied subcutaneously in the ratio of 1 mL/45 kg of BW. At the end of the experiment (d 56), animals were lighter than on d 0 in both treatments (P < 0.05). However, calves that received the ITM treatment presented lower body weight (P < 0.05) on d 56, compared to those in the control group. No significant difference (P > 0.05) was observed on the concentrations of oxidative stress enzymes. Moreover, no significant difference (P > 0.05) was observed in the plasmatic parameters; these were at normal range or slightly below the concentrations described for the species. We concluded that, in a feed restriction condition, the use of ITM in weaned calves did not improve performance, and the concentration of oxidative stress enzymes, and biochemistry variables. Therefore, we do not recommend using injectable trace minerals in the concentrations used in this study in animals under such stressful conditions.

Effects of road transportation or droving on the weight and metabolism of young bulls.

This study evaluated the effects of the mode of transportation on weight and metabolism of young bulls, which are generally transported by two systems: droving and truck. This experiment consisted of two phases: transportation and refeeding and involved transportation by droving and truck. Fifty young Nellore bulls were separated in equal numbers in both groups, droving group and truck group. In the transportation phase, animals were moved, in a 640-km journey. The refeeding phase consisted of 84 days and commenced after the animals arrived at the fattening farm. The effect of the transportation system on animals' weight, metabolic hormones, and serum biochemistry was assessed after 28, 56, and 84 days. During the transportation phase, animals in the droving group lost 10.11 kg and animals in the truck group gained 13.1 kg. The truck group showed 20.5 kg of weight gain at the end of the refeeding phase. The highest triiodothyronine (T3) and thyroxine (T4) concentrations were observed on days 0 and 60 in the transportation phase in both droving and truck groups. The serum cortisol concentration was higher in the droving group than in the truck group on day 56 of the refeeding phase. The IGF-I concentrations were higher during the refeeding phase in the droving group than in the truck group. Our results showed that transportation by droving leads to increased weight loss and reduced further weight gain compared to transportation by truck and that serum concentrations of T4, cortisol, and insulin-like growth factor (IGF-I) hormones are altered by the transportation system.