Increasing methionine availability in dairy cow diets during the first third of lactation may enhance their performance and health. The aim of this study was to determine the effect of supplementing rumen-protected methionine (Smartamine® M, SM) in a lactation diet with protein and energy levels calculated according to the literature. Seventy-six multiparous Holstein cows (39.1 ± 6.8 kg of milk/d and 65 ± 28 DIM) were assigned to 1 of 2 dietary treatments (38/treatment) according to a randomized complete block design with a 2-wk (covariate) and 10-wk experimental period. Treatments were a basal diet (CON; 3.77 Lys:1Met); and CON + 23 g SM (2.97 Lys:1 Met). Individual milk samples were taken every 2 weeks to determine milk composition. Blood was collected from 24 cows on d+30 d to measure plasma AA levels. Body weight and body condition score (BCS) were measured at the beginning and the end of the experiment. The SM diet promoted higher milk yield (41.7 vs. 40.1 kg/d; P = 0.03). Energy-corrected milk yield (41.0 vs. 38.0 kg/d), milk protein yield (1.30 vs. 1.18 kg/d), milk protein (3.14% vs. 2.97%) and casein (2.39% vs. 2.28%) were also different (P < 0.01) as well as milk fat yield (1.42 vs. 1.29 kg/d; P = 0.02). A trend (P = 0.06) for higher milk fat % (3.41% vs. 3.21%) was observed. Both diets resulted in similar body weight, but CON-fed cows tended (P = 0.08) to have higher BCS. Higher plasma methionine levels were determined with SM compared with CON (29.6 vs. 18.4 μM; P < 0.01), but lysine and histidine were not different. Dietary supplementation of RPM improved productive performance by increasing milk yield and milk components yields, suggesting better dietary AA utilization when Met levels are adjusted in Lys-adequate lactation diets.

RESUMOObjetivou-se avaliar prevalência de cistos ovarianos em vacas leiteiras de alta produção, no pós-parto, submetidas ao regime de dieta total em três sistemas diferentes: Compost Barn, Free Stall e confinamento a céu aberto no sudoeste do estado de Goiás. Foram avaliadas 1600 vacas, HPB, de sete rebanhos, das quais 792 (49,5%) estavam vazias e com atraso nos protocolos reprodutivos. Ao exame ultrassonográfico o escore ovariano foi classificado em: Grau 1 (61,4%), Grau 2 (18,1%), Grau 3 (4,0%) e Cistos Ovarianos (16,5%). Quanto ao sistema de produção as prevalências de cistos foram: 16% no Free Stall, 17,2% no Compost Barn e 16,2% no confinamento a céu aberto, diferenças somente numéricas, mas não significativas estatisticamente. 84,7% (n=131) dos animais estavam em anestro, na presença do diagnóstico cisto folicular. 67,7% desses animais, situavam-se entre 60 a 180 dias pós-parto. Divididos em 27,5% entre 60 e 90 dias, 24,5% entre 91 e 120 dias, 15,5% entre 121 e 150 dias e 32,5% entre 151 e 500. A prevalência dos cistos em função do número de lactações foi: 29,8% na primeira, 26,7% na segunda, 24,4% na terceira, 5,3% na quarta, 4,6% na quinta e 9,2% na sexta, resultados estatísticos significativos para maior ocorrência de cistos nas três primeiras lactações. Quanto ao escore de condição corporal 62,6% das vacas com cisto ovariano mostraram-se com escore entre 2,0 a 2,5, 25,2% entre 2,6 a 3,0 e 12,2% entre 3,1 a 4,0, resultados significativos, e a chance de vacas em balanço energético negativo desenvolverem cistos foi 5,1 vezes maior, quando comparadas com animais em escore corporal ideal. Os cistos foliculares apresentam-se com elevada casuística em vacas de alta produção leite, impactando em subfertilidade e prejuízos importantes na pecuária leiteira mundial, assim, faz-se necessário outros estudos visando o desenvolvimento de medidas preventivas mais eficazes no controle deste quadro. ABSTRACTThis study aimed to evaluate the follicular cysts prevalence in high production dairy cows, post-partum, under total diet regime in three different systems: Compost Barn, Free Stall and opened feedlot. There were evaluated 1600 cows, HPB, seven flocks, of which 792 (49.5%) were empty and late in the reproductive protocols. The examination sonographic ovarian score was distributed as: Score 1 (61.4%), Score 2 (18,1) Score 3 (4.0%) and Cystic Ovary (16.5%). As for the production system the cysts prevalence were 16% in Free Stall, 17.2% in Compost Barn and 16.2% in opened feedlot, without significant difference. 84.7% (n = 131) of animals were in anestrus in the presence of diagnosis follicular cyst. 60.7% of animal with follicular cysts were 60 to 180 days postpartum. Divided in 27.5% between 60 and 90 days, 24.5% between 91 and 120 days, 15.5% between 121 and 150 days and 32.5% between 151 and 500 postpartum. The cysts prevalence according to lactation number were: 29.8% in first, 26.7% in second, 24.4% in third, 5.3% in fourth, 4.6% in fifth and 9.2% in sixth, statistically significant results to higher cysts occurren...

Increasing methionine availability in dairy cow diets during the first third of lactation may enhance their performance and health. The aim of this study was to determine the effect of supplementing rumen-protected methionine (RPMet) in a lactation diet containing adequate protein and energy levels. Seventy-six multiparous Holstein cows (39.1 ± 6.8 kg of milk/d and 65 ± 28 DIM) were assigned to 1 of 2 dietary treatments (38/treatment) according to a randomized complete block design with a 2-wk (covariate) and 10-wk experimental period. Treatments were a basal diet (CON; 3.77 Lys:1Met); and CON + 14 g RPMet (2.97 Lys:1 Met). Individual milk samples were taken every 2 weeks to determine milk composition. Blood was collected from 24 cows on d+30 d to measure plasma AA levels. Body weight and body condition score (BCS) were measured at the beginning and the end of the experiment. The SM diet promoted higher milk yield (41.7 vs. 40.1 kg/d; P = 0.026), energy-corrected milk yield (41.0 vs. 38.0 kg/d; P ≤ 0.01), milk protein yield (1.30 vs. 1.18 kg/d; P ≤ 0.01), and milk fat yield (1.42 vs. 1.29 kg/d; P = 0.02). Higher milk protein (3.14% vs. 2.97%; P ≤ 0.01) and casein (2.39% vs. 2.28%; P ≤ 0.01) and a trend ( P = 0.06) for higher milk fat % (3.41% vs. 3.21%) were also observed. Both diets resulted in similar body weight, but CON-fed cows tended ( P = 0.08) to have higher BCS. Higher plasma methionine levels were determined with SM compared with CON (29.6 vs. 18.4 μ M ; P < 0.01), but lysine and histidine were not different. Dietary supplementation of RPM improved productive performance by increasing milk yield and milk components yields, suggesting better dietary AA utilization when Met levels are adjusted in Lys-adequate lactation diets.