Location: Livestock Issues ResearchTitle: Impacts of pre- and postpartum heat stress abatement on physiology and performance of grazing Bos indicus-influenced cow-calf pairs
|IZQUIERDO, VINICIUS - University Of Florida|
|SILVA, JOAO - University Of Florida|
|SILVA, HIRAN - University Of Florida|
|RANCHES, JULIANA - Eastern Oregon Agricultural Research|
|Carroll, Jeffery - Jeff Carroll|
|BITTAR, JOAO - University Of Florida|
|VENDRAMINI, JOAO - University Of Florida|
|MORIEL, PHILIPE - University Of Florida|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/2022
Publication Date: 5/1/2023
Citation: Izquierdo, V.S., Silva, J.L., Silva, H.M., Ranches, J., Carroll, J.A., Sanchez, N.C., Bittar, J.H., Vendramini, J.M., Moriel, P. 2023. Impacts of pre- and postpartum heat stress abatement on physiology and performance of grazing Bos indicus-influenced cow-calf pairs. Journal of Animal Science Supplement. 101(1):41-42.
Technical Abstract: This study evaluated the impacts of heat abatement during pre- and postpartum on performance of beef heifers and their calves. On day 0, 64 Brangus beef heifers (21 mo of age) were stratified by body weight (BW; 454 ± 37 kg) and body condition score (BCS; 6.3 ± 0.28) and allocated into 1 of 16 bahiagrass pastures (1 ha and 4 heifers/pasture). Treatments were randomly assigned to pastures (8 pastures/treatment) and consisted of heifers provided (SH) or not (NSH) access to artificial shade from day 0 to 133 (83 ± 4 d prepartum until 50 ± 4 d postpartum). Shade structures were removed on day 133. Calves were weaned on day 203 (119 ± 19 d of age) and were transferred to 1 of 16 drylot pens (3 to 4 calves/pen) and limit-fed a soybean hulls-based diet (3.25% of BW) until day 268. Heifer BCS on days 55, 133 and 203 were greater (P = 0.01) for SH vs. NSH heifers. Plasma glucose did not differ (P = 0.29), whereas plasma IGF-1 were greater (P = 0.05) on days 55 and 133 for SH vs. NSH heifers. Calf BW was less (P = 0.05) for NSH vs. SH calves at birth, did not differ (P = 0.44) at weaning, and was less (P = 0.05) for SH vs. NSH calves at drylot exit. Plasma haptoglobin concentrations were greater (P = 0.05) and serum titers against bovine respiratory syncytial virus tended (P = 0.10) to be less for SH vs. NSH calves after vaccination. Serum titers against all remaining viruses did not differ (P = 0.24) between treatments. Therefore, heat abatement during pre- and post-partum increased heifer BCS and plasma IGF-1 during late gestation, increased calf birth BW, reduced calf post-weaning growth, and had minor changes to calf humoral immune function.