RESUMOEstudou-se a exigência de metionina + cistina total para codornas de corte em crescimento durante os períodos inicial (sete a 21 dias) e final (22 a 42 dias de idade). O delineamento experimental foi inteiramente casualizado, com cinco repetições de 13 codornas por unidade experimental. Os tratamentos consistiram de seis níveis de metionina + cistina total (0,73; 0,79; 0,85; 0,91; 0,97 e 1,03%). Foram estudadas as variáveis: ganho de peso (g), peso final no período (g), consumo de dieta (g) e conversão alimentar (g de dieta/g de peso). As respostas de desempenho foram obtidas por meio de modelos de regressão linear e quadrática. Codornas de corte alimentadas com dietas contendo 0,95% de metionina + cistina total no período inicial (sete a 21 dias) e 0,73% de metionina + cistina total no período final (22 a 42 dias) de criação obtêm máximo ganho de peso.Palavras-chave: codorna, exigência nutricional, aminoácido, ganho de peso, consumo alimentar, conversão alimentar ABSTRACT Total methyonine + cystine requirements during the initial (7-21 days of age) and final period ( 22-

This study evaluated the growth and immune function of beef calves born to cows supplemented with bakery waste containing 2 concentrations of crude fat. On day 0 (~90 d before calving), 108 multiparous Brangus crossbred cows were stratified by body weight (BW; 551 ± 65 kg) and body condition score (BCS, 5.5 ± 0.9) and randomly allocated into 1 of 18 bahiagrass (Paspalum notatum) pastures (6 cows and 4.3 ha/pasture). Treatments were randomly assigned to pastures (6 pastures/treatment) and consisted of no prepartum supplementation (NOSUP) and isocaloric and isonitrogenous supplementation of low-fat (LFAT; 6.4% crude fat) or high-fat (HFAT; 10.7% crude fat) bakery waste from day 0 to 70 (1 kg DM/cow/day). Calves were weaned on day 292 (201 ± 17 d of age). Then, 15 heifers/treatment were randomly selected and assigned to drylot pens from day 300 to 345 and vaccinated against respiratory pathogens on days 300 and 315. Cow BCS near calving (day 70) was the least (P ≤ 0.05) for NOSUP cows and did not differ (P = 0.12) between LFAT and HFAT cows. Cow BCS at the start of the breeding season (day 140) was greater (P = 0.05) for HFAT vs. NOSUP cows and intermediate (P ≥ 0.35) for LFAT cows. Plasma concentrations of total polyunsaturated fatty acids (PUFA) in HFAT cows did not differ (P ≥ 0.76) compared with LFAT cows but were greater (P ≤ 0.05) compared to NOSUP cows on day 70. Final pregnancy percentage did not differ (P ≥ 0.26) among treatments, but a greater percentage of HFAT cows calved (P ≤ 0.05) their second offspring during the first 21 d of the calving season compared to NOSUP and LFAT cows (bred by natural service). Weaning BW was greatest (P ≤ 0.05) for LFAT and least for NOSUP calves. Maternal treatments did not impact (P ≥ 0.11) post-weaning growth and total DM intake of calves. Average plasma cortisol concentrations were greater (P = 0.03) for NOSUP vs. HFAT calves and intermediate for LFAT calves (P ≥ 0.26). Serum titers against infectious bovine rhinotracheitis (IBR) and bovine respiratory syncytial virus (BRSV) were greater or tended to be greater (P ≤ 0.08) for HFAT vs. LFAT calves and intermediate (P ≥ 0.27) for NOSUP calves at the end of preconditioning. Thus, supplemental fat concentration fed to late-gestating beef cows had variable effects on calf performance. Low-fat bakery waste led to greatest calf preweaning growth, whereas high-fat bakery waste enhanced maternal reproduction and had minor benefits to calf humoral immune function.

This study evaluated the growth and immune response of beef calves born from Bos indicus-influenced beef heifers provided pre- and post-partum heat abatement on pasture. At 83 ± 4 d prepartum (day 0), 64 Brangus crossbred beef heifers (~¼ Bos indicus) were stratified by body weight (BW; 454 ± 37 kg) and body condition score (BCS; 6.3 ± 0.28; scale 1 to 9), and then 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 (4.5 m 2 of shade area/heifer) from 83 d prepartum to 50 d post-partum (day 0 to 133). Heifers and calves were managed similarly from day 133 until the start of the breeding season (day 203). Calves were weaned on day 203 (at 119 ± 19 d of age), limit-fed the same drylot diet at 3.5% of BW (DM basis) day 209 to 268 (3 to 4 calves/pen; 8 pens/treatment) and vaccinated against respiratory disease pathogens on days 222 and 236. Heifer intravaginal temperatures from day 35 to 42 were lower (P ≤ 0.03) for NSH vs. SH heifers from 0000 to 0800 h but greater (P ≤ 0.05) for NSH vs. SH heifers from 1100 to 1800 h. Heifer intravaginal temperature from day 126 to 132 did not differ (P = 0.99) between NSH and SH heifers. Heifers assigned to NSH had greater respiration rates from day 20 to 96 (P ≤ 0.0007), greater plasma concentration of cortisol on days 35 (P = 0.07) and 55 (P = 0.02), less plasma concentration of insulin-like growth factor 1 (IGF-1) on day 35 (P = 0.10), 55 and 133 (P ≤ 0.05), and less BCS from day 55 to 203 (P ≤ 0.01) compared to SH heifers. Calves born from NSH heifers had less birth BW (P = 0.05), greater overall plasma haptoglobin concentrations (P = 0.05), greater seroconversion against bovine respiratory syncytial virus on day 222 (P = 0.02), tended to have greater ADG from day 209 to 268 (P = 0.07), and had greater BW on day 268 (P = 0.05) compared to SH offspring. Plasma concentrations of cortisol and serum titers against other respiratory disease pathogens did not differ (P ≥ 0.15) between NSH and SH offspring. Hence, removing maternal access to artificial shade: (1) increased prepartum intravaginal temperature and plasma concentrations of cortisol but reduced prepartum BCS and plasma concentrations of IGF-1 in grazing Bos indicus-influenced beef heifers; and (2) increased post-weaning BW gain and had positive effects on humoral immune response of their offspring.