This experiment compared physiological and productive responses in finishing beef cattle managed under heat stress conditions, and supplemented (SUPP) or not (CON) with an immunomodulatory feed ingredient (Omnigen-AF; Phibro Animal Health, Teaneck, NJ). Crossbred yearling cattle (¾ Bos taurus × ¼ Bos indicus; 64 heifers and 64 steers) were ranked by initial body weight (BW) (440 ± 3 kg) and sex, and allocated to 1 of 16 unshaded drylot pens (8 heifers or steers/pen). Pens within sex were randomly assigned to receive SUPP or CON (n = 8/treatment). Cattle received a total-mixed ration (91% concentrate inclusion and 1.21 Mcal/kg of net energy for gain; dry matter [DM basis]) during the experiment (day 0 to 106). The immunomodulatory feed was offered as a top-dress to SUPP pens (56 g/d per animal; as-fed basis) beginning on day 7. Cattle BW were recorded on day 0, 14, 28, 42, 56, 70, 84, 98, and 106. Feed intake was evaluated from each pen by recording feed offer daily and refusals biweekly. Intravaginal temperature of heifers was recorded hourly from day 1 to 6, 29 to 41, and 85 to 97. Environmental temperature humidity index (THI) was also recorded hourly throughout the experiment, and averaged 79.8 ± 0.6. Concurrently with BW assessment, hair samples from the tail-switch were collected (3 animals/pen) for analysis of hair cortisol concentrations. Blood samples were collected on day 0, 28, 56, 84, and 106 from all animals for plasma extraction. Whole blood was collected on day 0, 56, and 106 (3 animals/pen) for analysis of heat shock protein (HSP) 70 and HSP72 mRNA expression. Cattle were slaughtered on day 107 at a commercial packing facility. Results obtained prior to day 7 served as independent covariate for each respective analysis. Heifers receiving SUPP had less (P ≤ 0.05) vaginal temperature from 1500 to 1900 h across sampling days (treatment × hour, P < 0.01; 39.05 vs. 39.19 °C, respectively; SEM = 0.04), when THI ranged from 85.3 to 90.1. Expression of HSP70 and HSP72 was less (P ≥ 0.03) for SUPP cattle on day 106 (22.6- vs. 51.5-fold effect for HSP70, SEM = 9.7, and 11.0- vs. 32.8-fold effect for HSP72; treatment × day, P ≤ 0.04). No treatment effects were detected (P ≥ 0.22) for performance, carcass traits, plasma concentrations of cortisol and haptoglobin, or hair cortisol concentrations. Results from this study suggest that SUPP ameliorated hyperthermia in finishing cattle exposed to heat stress conditions, but such benefit was not sufficient to improve productive responses.

This experiment evaluated the impacts of administering a bovine appeasing substance (BAS) to beef calves at weaning on their performance, physiological responses, and behavior during a 42-d preconditioning program. Eighty calves (40 heifers and 40 steers; 90% British × 10% Nellore) were weaned at 233 ± 2 d of age (d 0), ranked by sex, weaning age and body weight (BW), and assigned to receive BAS (IRSEA Group, Quartier Salignan, France; n = 40) or placebo (diethylene glycol monoethyl ether; CON; n = 40). Treatments (5 mL) were topically applied to the nuchal skin area of each animal following dam separation. Within treatment, calves were allocated to 1 of 8 drylot pens (4 pens/treatment; pen being the experimental unit) and received a free-choice total mixed ration (TMR) from d 0 to 42, intake of which was assessed daily. Live behavior observations were conducted on d 1, 2, 4, 8, 16, and 32. Temperament was assessed and blood samples collected via jugular venipuncture on d -21, 0, 3, 7, 14, 28, and 42. Hair samples were collected from the tail switch on d 0, 14, 28, and 42. Calves were vaccinated against bovine respiratory disease viruses on d -21 and 0. Average daily gain from d 0 to 42 did not differ between treatments (P = 0.57), but was greater (P = 0.05) in BAS vs. CON calves from d 0 to 28. Intake of TMR was greater (P = 0.05) during the first week for BAS vs. CON calves (treatment × week; P = 0.08). Mean proportion of calves feeding simultaneously, and performance of social and play behaviors were greater (P ≤ 0.05) for BAS vs. CON calves. Escape attempts were greater (P & 0.01) for BAS vs. CON calves on d 1 (treatment × day; P = 0.03). Exit velocity was greater (P = 0.04) for CON vs. BAS calves on d 14 and tended (P = 0.10) to be greater for CON vs. BAS calves on d 7 (treatment × day; P = 0.03). Mean plasma concentrations of haptoglobin were greater (P = 0.02) in CON vs. BAS calves. Hair cortisol concentrations were greater (P = 0.05) in CON vs. BAS calves on d 14 (treatment × day; P = 0.03). Mean serum concentrations of antibodies against bovine viral diarrhea virus was greater (P = 0.02) in BAS vs CON calves. Collectively, BAS administration to beef calves at weaning alleviated stress-induced physiological reactions, improved temperament evaluated via chute exit velocity, enhanced humoral immunity acquired from vaccination, and appear to have accelerated adaptation to novel management scheme and environment.

This experiment evaluated the impacts of bovine appeasing substance (BAS) administration on performance, behavioral, and physiological responses of beef calves upon weaning. Eighty Angus-influenced calves (40 heifers, 40 steers) were weaned at 233 ± 2 d of age (d 0), ranked by age and body weight (BW), and assigned to receive BAS (Nutricorp, Araras, SP, Brazil; n = 40) or placebo (diethylene glycol monoethyl ether; CON; n = 40). Treatments (5 mL) were topically applied to the nuchal skin area of each animal. Within treatment, calves were allocated to 1 of 8 drylot pens (4 pens/treatment) and received a free-choice total mixed ration (TMR) from d 0 to 42, intake of which was assessed daily. On d 0, calves were fitted with a pedometer behind their right shoulder, and pedometer results were recorded weekly during the experiment (d 0 to 42) concurrently with full BW collection and temperament evaluation. Blood samples were collected on d 0, 3, 7, 14, 28, and 42, and hair samples were collected from the tail switch on d 0, 14, 28, and 42. Average daily gain from d 0 to 42 did not differ between treatments (P = 0.52), but was greater (P = 0.05) in BAS vs. CON calves from d 0 to 28. Intake of TMR was greater during the first week for BAS vs. CON calves (P = 0.05), and similar (P ≥ 0.44) from wk 2 to 6 (treatment × week; P = 0.08). Exit velocity was greater (P = 0.03) for CON vs. BAS calves on d 14 and tended (P = 0.08) to be greater for CON vs. BAS calves on d 7 (treatment × day; P = 0.04). Physical activity was greater for CON vs. BAS calves on d 1 (P &lt; 0.01), but greater (P = 0.01) in BAS vs. CON on d 2 (treatment × day; P = 0.01). Mean plasma concentrations of haptoglobin were greater (P = 0.03) in CON vs. BAS calves during the experiment. Hair cortisol concentrations were greater (P = 0.0 5) in CON vs. BAS calves on d 14 (treatment × day interaction; P = 0.03). Results from this experiment indicate BAS calves habituated to their environment more rapidly through increased physical activity, which facilitated a lessened stress response associated with weaning, and accelerated adaptation to a novel environment. This was manifested through improved TMR intake and BW gain during the initial period of the experiment. Collectively, results suggest use of BAS as a strategy to improve calf welfare and productivity upon weaning.

RESUMO O objetivo desse trabalho foi avaliar a substituição parcial do farelo de soja por farinha de carne e ossos (FCO) e da suplementação com butirato de sódio (BS) sobre o desempenho de frangos de corte. Foram utilizados 140 pintos distribuídos em DIC em fatorial 2x2 (ausência e presença de BS x ausência e presença de FCO) com 5 repetições. O desempenho foi avaliado semanalmente por meio do consumo de ração (CR), ganho de peso (GP), conversão alimentar (CA) e viabilidade criatória (VC). De 1 a 14 dias e a utilização de FCO reduziu o CR e o GP, entretanto a inclusão de BS reverteu esses resultados. A inclusão de BS aumentou o CR e o GP de 1 a 7 e 1 a 42 dias. Concluiu-se que tanto a substituição do farelo de soja por FCO como a suplementação com BS são alternativas viáveis na alimentação de frangos de corte. Palavras-chave: ácidos orgânicos; consumo de ração; conversão alimentar; farinhas de origem animal; ganho de peso.