Effects of rumen-protected methionine supplementation on the performance of high production dairy cows in the tropics

Abstract

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.

Feasibility of Supplying Ruminally Protected Lysine and Methionine to Periparturient Dairy Cows on the Efficiency of Subsequent Lactation

“…Some EAAs are considered limiting for milk protein synthesis under specific dietary conditions in dairy cows, typically Met and Lys ( 17 ), and probably His. The increase in milk protein percentage and yield observed in this study in response to RPL and RPM agreed with what was previously obtained ( 9 , 14 , 16 , 61 , 62 ), but not always ( 27 , 63 , 64 ). Consistent with other studies, there was a positive response of dietary RPL and RPM supply on milk yield for transition and lactating and beef cows ( 13 , 14 , 16 , 61 , 65 , 66 ), but this response is not universal ( 12 , 27 , 67 – 69 ).…”

“…The lower MUN shown in this study indicates greater efficiency of N utilization. Lowered MUN has previously been observed by supplying RPAA form, including Met, Lys, leucine, threonine, and isoleucine separately or two in combination to lactating dairy cows ( 28 , 29 , 78 ), with no response in others ( 13 , 27 , 43 , 61 , 68 ). In this study, continual supplementing RPAA to transition and lactating dairy cows may improve udder health as indicated by the lowered milk SCC, as reported earlier in this study during the perinatal period ( 18 , 29 ).…”

“…In this study, milk lactose yield and protein increased with RPAA supply resulting in the use of a greater proportion of the unsupplemented IAA for milk protein. Junior et al ( 61 ) demonstrated that improving AA absorption efficiency increases milk production in high-lactating dairy cows. Metabolizable protein supply has been recognized as the limiting factor for the absorption of AA in the mammary gland, which will be decided the yields of protein, lactose, and subsequently milk production ( 70 , 71 ), as milk yield is a derivative from these components.…”

Meta-Analysis of Rumen-Protected Methionine in Milk Production and Composition of Dairy Cows

“…The retrieved studies were screened according to the corresponding inclusion criteria. After excluding the duplicate and unqualified literature, the meta-analysis included 14 studies, as shown in Table 1 [ 1 , 2 , 5 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. To make it easier to visualize the studied datasets, the mean, maximum, minimum, and standard deviation of each study parameter are summarized in Table A1 of Appendix A .…”

Regulation of Milk Protein Synthesis by Free and Peptide-Bound Amino Acids in Dairy Cows

“…Met is the first limiting AA for ruminants [17]. Increasing the Met supply by feeding diets supplemented with RPM can increase the milk yield and MP yield [37,38,42,50]. The resistance to rumen degradation of many Met analogs have been studied.…”