Responses of Dairy Cows to Supplemental Rumen-Protected Forms of Methionine and Lysine

Abstract

Multiparous Holstein cows at six universities were utilized to examine effects of ruminally protected methionine and lysine on lactational performance. Three hundred and four cows began the study; 259 cows were included in the production analysis. Following a 21-d standardization period, cows received a basal diet of corn silage and ground corn supplemented with one of five dietary treatments, which were supplements of soybean meal or corn gluten meal, the latter with zero and three combinations of protected methionine and lysine (methionine; methionine and lysine; methionine and double (2x) lysine). Treatment effects were evaluated during early, mid, late, and total lactation (22 to 112, 113 to 224, 225 to 280, and 22 to 280 d postpartum, respectively). On a DM basis, ratios of forage to concentrate (50:50, 60:40, and 70:30) increased, and dietary CP (16.0, 14.5, and 13.0%) decreased during the three periods of lactation. Amount of amino acid supplementation also decreased (15, 12, and 9 g/d methionine; 20, 16, and 12 g/d lysine; and 40, 32, and 24 g/d 2x lysine) with period of lactation. Actual and least squares means for milk, FCM, and milk protein yields were greater for soybean than for corn gluten meal during early, mid, and total lactation. In addition, these variables responded linearly to lysine in early lactation. Response to lysine was quadratic during mid and total lactation for these variables. Differences in nutrient intake explained production responses to protein sources but not to lysine. Serum amino acid responses primarily reflected differences in dietary protein source and rumen-protected amino acid.

Efeito da sobrealimentação com fontes de proteína de diferentes degradabilidades sobre a ovulação em ovelhas Santa Inês

“…No entanto, o glúten de milho na quantidade utilizada neste experimento não reduziu o consumo de MS. A proporção desse ingrediente na dieta (7,45% da MS) foi próxima ao nível máximo consumido por cordeiras Santa Inês (7,91%) em experimento conduzido por Salvador (2007). Santos et al (1998), ao analisar três artigos (Holter et al, 1992;Polan et al, 1991;Wohlt et al, 1991), em que o farelo de soja foi totalmente substituído pelo glúten de milho em dietas à base de silagem de milho para vacas leiteiras, observaram menor ingestão de MS. Em nenhum dos trabalhos analisados a causa da redução na ingestão de MS foi relatada. No entanto, a redução no consumo pode ter como causa a baixa palatabilidade do glúten de milho (Teixeira, 1997).…”

Evaluation of feather meal as a source of sulfur amino acids for growing steers.

“…These amounts of actual metabolizable Met were 0, 1, 2, 3, 4, or 6 g/d. Smartamine M contains Met (63% metabolizable Met) encapsulated in a pHsensitive coating (poly-2-vinyl-pyridine-co-styrene) that is stable at a ruminal pH of 5.4 yet loses its integrity when it enters the abomasum (Polan et al, 1991). Six calves were randomly assigned to the urea control and eight calves each to MBM, MBM plus 1% FTH, and MBM plus 2% FTH.…”

The effects of methionine supplementation upon milk composition and production of forage-fed dairy cows

“…Blood or plasma AA concentrations have been used to assess the effectiveness of ruminally protected preparations in delivering amino acids to the systemic circulation (Papas et al 1984;Polan et al 1991). In the current study, the basal concentrations of Met in blood were similar to those reported elsewhere (Papas et al 1984;Illg et al 1987;Rogers et al 1987;Donkin et al 1989).…”