RESUMO
Researchers have reported the benefits of feeding rumen-protected methionine (RPM) during the peripartum on the health parameters of dairy cows. Rumen-protected methionine has reportedly improved milk yield, milk components and liver health, but the literature is scarce on its effects in commercial herds. Therefore, we aimed to determine the effects of feeding RPMet (Smartamine M®, Adisseo Inc., Antony, France) prepartum (8 g per cow per day) and postpartum (15 g per cow per day) on performance, metabolic profile, and culling rate of Holstein cows in a commercial herd. One-hundred and 66 (n = 166) Holstein cows, 58 nulliparous and 108 parous, were randomly assigned to 1 of 2 dietary treatments, consisting of TMR top-dressed with RPMet (2.35 and 2.24% Met of MP for close-up and fresh cows, respectively) or without (control, CON, (2.03 and 1.89% Met of MP for close-up and fresh cows, respectively), fed from 21 ± 6 d prepartum until 16 ± 5 d postpartum. From 17 d in milk (DIM) until dry-off, all cows received RPMet. Daily milk yield was recorded, and milk samples were collected in the first and second weeks after calving to determine their composition. Blood samples were collected before the morning feeding on -14, -7, +1, +7, and +14 d relative to calving. Mortality and morbidity were recorded during the first 60 DIM. Cows supplemented with RPMet had greater milk yield during the first 16 DIM (31.76 vs. 30.37 kg/d; SEM = 1.04, respectively), and had greater milk fat content (4.45 vs. 4.10%; SEM = 0.11, respectively), but not milk total protein (3.47 vs. 3.39%; SEM = 0.04, respectively) and casein contents (2.74 vs. 2.66%; SEM = 0.04, respectively) than CON cows. Cows in RPMet had increased plasma Met concentrations than cows in CON (24.9 vs. 21.0 µmol/L; SEM = 1.2, respectively). Although morbidity was similar between treatments, the culling rate from calving until 60 DIM was lower for RPMet cows than for CON cows (2.4 vs. 12.1%; SEM = 0.02). In conclusion, cows receiving RPMet have greater milk yield, improved milk fat content, and a lower culling rate at 60 DIM than CON cows.
RESUMO
O uso de regimes de corte em estádio vegetativo para os cereais de inverno é interessante quando se busca intensificar a produção de alimento volumoso para ruminantes. No entanto, é necessário se averiguar o impacto desse manejo sobre as características das silagens resultantes. Dessa forma, o objetivo do experimento foi avaliar o valor nutricional e a estabilidade aeróbia de silagens de cereais de inverno, submetidas a regimes de corte no estádio vegetativo, prévio ao corte para ensilagem. Os cereais utilizados foram trigo (Triticum aestivum cv. BRS Gralha Azul), cevada (Hordeum vulgare cv. BRS Brau), aveia-branca (Avena sativa cv. URS Guará), aveia- preta (Avena strigosa cv. Embrapa 139) e triticale (X Triticosecale cv. IPR 11), associados a três regimes de corte: sem cortes prévios (silagem exclusiva); um corte; e com dois cortes em estádio vegetativo e subsequente produção de silagem. Na avaliação nutricional, a cevada apresentou valores baixos de FDA (311,7 e 375,3g kg de MS-1) e altos de NDT (569,2 e 533,4g kg de MS-1) para os sistemas com um e dois cortes, respectivamente. Na avaliação da estabilidade aeróbia, os materiais foram bastante estáveis após a abertura dos silos, com exceção da aveia-branca e da aveia-preta, no regime sem cortes. As silagens de triticale e de cevada apresentaram as maiores estabilidades nutricionais com o aumento no número de cortes.(AU)
The use of cutting regimes in vegetative stage for winter cereals is interesting when it seeks to intensify the forage production for ruminants. However, it is necessary to ascertain the impact of this management on the characteristics of the resulting silage. Thus, the aim of the experiment was to evaluate the nutritional quality and aerobic stability of winter cereal silages submitted to cutting regimes in vegetative stage, before ensiling. The materials used were: wheat (Triticum aestivum cv. BRS Gralha Azul); barley (Hordeum vulgare cv. BRS Brau); white oat (Avena sativa cv. URS Guará); black oat (Avena strigosa cv. Embrapa 139) and triticale (X Triticosecale cv IPR 11); associated with three management strategies: without previous cuts (Only silage), one cut and two cuts in vegetative and posterior silage making. Barley owned low values of ADF (311.7 and 375.3g kg de DM-1) and high TDN (569.2 and 533.4g kg de DM-1) for one and two-cut system, respectively. For aerobic stability, materials were quite stable after opening the silos, with the exception of black and white oat in management without cuts. Triticale and barley silage had the highest nutritional stability with the increase in the number of cuts.(AU)