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

Abstract

. 1999. The effects of methionine supplementation upon milk composition and production of forage-fed dairy cows. Can. J. Anim. Sci. 79: [235][236][237][238][239][240][241]. Two experiments (mid-and late lactation) were conducted to test whether methionine (Met) limited milk production in Friesian cows fed sole diets of fresh perennial ryegrass-white clover pasture. In mid-lactation (exp. 1), 26 cows were assigned to one of three treatments: ruminally protected oral DL-Met (15 g d -1 ), continuous intrajugular infusion of L-Met (15 g d -1 ) and control. Twelve animals from exp. 1 were used during late lactation (exp. 2) and distributed in two experimental groups: ruminally protected oral DL-Met (15 g d -1 ) and control. Dry matter, metabolizable energy, crude protein and Met intakes, milk yield and composition and blood Met, cysteine and urea were measured. Oral and intravenous Met supplementation increased blood Met concentration by 50-90% compared with controls. Met supplementation did not alter the concentration of milk fat, protein or lactose in either experiment. Met supplementation had no significant effects on yields of fat, lactose, casein, whey proteins or non-protein nitrogen during mid-lactation. In late lactation, Met supplementation did not affect milk protein composition or yield of milk components, with exception of a decrease (P < 0.05) in the yield of β-casein. Intravenous Met supplementation increased (P < 0.05) the efficiency of conversion of pasture N to milk protein in mid-lactation. ) sur la composition et la production de lait ont été déter-minés chez les vaches de race Frisonne en mi-lactation (expérience 1) et fin de lactation (expérience 2). Les vaches ont été alimentées exclusivement avec du pâturage de raygrass et trèfle blanc fraîchement coupé dans les deux expériences. Dans l'expérience 1, 26 vaches en mi-lactation ont reçu un des trois traitements suivants: administration orale de la DL-méthionine protégée contre le dégradation ruminale, perfusion intraveineuse continue de la L-méthionine ou témoin. Dans l'expérience 2, 12 vaches de l'expérience 1 ont été utilisées en fin de lactation et distribuées en deux groupes expérimentaux: administration orale de la DL-méthionine protégée ou témoin. La complémentation orale et intraveineuse en méthionine a augmenté la concentration sanguine de méthionine. La complémentation orale et/ou intraveineuse en méthionine n'a pas modifié la concentration du gras, de la protéine et du lactose dans le lait en mi-et fin de lactation. La complémentation en méthionine n'a pas eu des effets significatifs sur la production de gras, de lactose, caséine, des protéines du lactosérum et de la fraction azotée non-protéique en mi-lactation. En fin de lactation, la complémentation orale en méthionine n'a pas affecté la production des constituants du lait ainsi que sa composition protéique à l'exception d'une diminution (P < 0.05) de la production de la β-caséine. La complémentation intraveineuse en méthionine a augmenté (P < 0.05) l'efficacité de la conversion de l...

Effects of Dietary Supplements of Folic Acid and Rumen-Protected Methionine on Lactational Performance and Folate Metabolism of Dairy Cows

“…Ingestion of RPM increased serum concentrations of methionine in a range similar to those reported in the literature (Aldrich et al, 1993;Overton et al, 1996;Pacheco-Rios et al, 1997;Rulquin and Delaby, 1997a, b;Robinson et al, 1998;Pisulewski and Kowalski, 1999;Vanhatalo et al, 1999;Krober et al, 2000;Pisulewski et al, 2002). Serum concentrations of homocysteine were also higher in cows fed RPM.…”

“…In a nonexhaustive review of the literature between 1993 and 2003, only 1 (Vanhatalo et al, 1999) effect of RPM fed to dairy cows reported an increase in milk production, and none described an effect on DMI (Aldrich et al, 1993;Guinard and Rulquin, 1995;Jurjanz et al, 1996;Overton et al, 1996;Armentano et al, 1997;Chilliard and Doreau, 1997;Pacheco-Rios et al, 1997Rulquin and Delaby, 1997a, b;Robinson et al, 1998;Blum et al, 1999;Pisulewski and Kowalski, 1999;Vanhatalo et al, 1999;Krober et al, 2000;Berthiaume et al, 2001;Younge et al, 2001;Pisulewski et al, 2002;Kowalski et al, 2003;Leonardi et al, 2003;Misciattelli et al, 2003;Noftsger and St-Pierre, 2003). The major effect of RPM supplements is an increase in milk protein concentration and yield (Guinard and Rulquin, 1995;Jurjanz et al, 1996;Armentano et al, 1997;Chilliard and Doreau, 1997;Pacheco-Rios et al, 1997Rulquin and Delaby, 1997b a, b;Krober et al, 2000;Kowalski et al, 2003;Leonardi et al, 2003;Misciattelli et al, 2003;Noftsger and St-Pierre, 2003). Overall, in the present experiment, RPM did increase milk crude protein (total nitrogen) and casein concentration but without any changes in milk protein yield.…”

Nutritional limitations to increased production on pasture-based systems

“…Since ME was the first-limiting nutrient in milk production in this simulation, supplementation of highquality pasture would first need to correct the deficiency in energy rather than AA supply, which might explain the inconsistent milk response of cows consuming high-quality pasture and fed supplemental rumen-undegradable protein (Kellaway & Porta, 1993;Minson, 1990). The generally poor milk response to supplemental methionine and lysine of cows grazing high-quality pasture (Pacheco-Rios et al 1997;Rusdi & van Houtert, 1997) would also tend to support this result.…”

Effect of duodenal infusion of methionine on milk yield and composition in ewes at late lactation fed hay-based diet

“…On the other hand, the effect of Met supplementation can be lower when it is associated with haybased diets and late lactation (La Henaff et. al., 1990;Pacheco-Rios et al, 1997).…”