Alpharetta, GA (August 5, 2019)
Researching the benefits of feeding rumen protected methionine and methionine analogues continues to receive significant interest. Nearly 60 new methionine-related abstracts were presented during this summer’s annual meeting of the American Dairy Science Association (ADSA). The ADSA annual meeting, reportedly the most comprehensive dairy science meeting in the world, attracted more than 1,900 attendees from 52 countries.
“Now that methionine is recognized as an essential nutrient with wide-ranging roles in dairy nutrition, its impact on production, health, and reproductive performance continues to be more fully explored,” said Brian Sloan, Global Ruminant Business Director, Adisseo. “For dairy farmers, supplemental methionine offers gains in the production of milk, milkfat and milk protein. It also offers longer-term gains in terms of health and reproductive performance.”
Notable among the recent research findings presented at the ADSA annual meeting were the following. Research from Cornell University explored the effect of calf starters, with either supplemental rumen protected methionine or methionine analogues, on calf growth and efficiency from 14 to 91 days of age. Contrasts among the methionine supplements indicated that the methionine analogue HMTBi, the isopropyl ester of the hydroxy analogue of methionine, improved feed intake and bodyweight gain post weaning with a tendency for a greater final bodyweight.
Additional research results from the Cornell lab of Dr. Mike Van Amburgh were presented. The research investigated the optimum quantity of an ideal profile of the 10 essential amino acids relative to metabolizable energy to feed to maximize milk performance and feed efficiency. Results confirmed the hypothesis that on a methionine and lysine basis at least 1.14 and 3.03 grams per MCal of metabolizable energy, respectively, are minimally necessary.
A Brazilian on-farm trial with two groups of animals – 65 + days in milk at the start of the trial and averaging 40 kgs of milk, with dietary treatments fed for 10 weeks — showed significant increases in energy corrected milk (+3 kg/day), milkfat percent (+0.20) and milk protein percent (+0.17), and improved daily milk component yields by 130 grams of fat and 110 grams of protein when a lysine adequate diet was complemented with Smartamine® M, to achieve a desired lysine to methionine ratio of 2.97 to 1. An interesting side note was optimum performance appeared associated with a plasma methionine concentration close to 30μM, as compared to 18.4μM for the control cows which were not supplemented with methionine.
Research at the University of Illinois evaluated the effects of feeding rumen protected methionine to 32 multiparous cows subjected to heat stress. The researchers concluded that heat stress negatively affected physiological and production parameters. The rumen protected methionine supported milk, milk protein and milkfat production.
Research at The Ohio State University investigated the effects of methionine sources on rumen fermentation and biohydrogenation of linoleic acid in vitro, as these impact milkfat depression. The researchers concluded that linoleic acid at 3% of substrate dry matter depressed feed digestibility and altered acetate and propionate production. However, methionine and the analogue of methionine, 2-Hydroxy-4-(Methylthio) Butanoic Acid (HMTBa), alleviated the negative effect of linoleic acid on fiber digestibility, and HMTBa produced more acetate and less propionate compared with linoleic acid, which did not occur for methionine. The changes in the biohydrogenation of linoleic acid by methionine and HMTBa did alter the biohydrogenation pathways that relate to milkfat depression.
Research from INRA in France investigated the effect of methionine, lysine, and histidine supplementation at both a low and high net-energy supply in dairy cows. The research showed that increasing the net energy supply increased milk protein yield and also increased milkfat yield. Better balancing amino acids increased the milk protein yield through a tendency to increase milk yield at both the high and low energy levels. This led to an overall increase in metabolizable protein efficiency.
Research conducted at the University of New Hampshire explored the feasibility of evaluating the methionine bioavailability of rumen protected technologies using the plasma amino acid dose-response technique without using ruminally cannulated animals. The researchers found that this could be done when using a reference rumen-protected amino acid supplement with a known bioavailability. According to the research results, the bioavailability of the test product used was 20.8% relative to the reference rumen protected methionine. The use of ruminally-cannulated cows was shown to not be needed.
Intake, lactation performance, and plasma amino acid concentrations for cows fed rumen-protected-methionine supplements:
| Item | Control | Smartamine® M | EB-Met | SEM | P-value |
| Dry Matter Intake (DMI), kg/d | 25.3 | 25.7 | 25.0 | 0.80 | 0.78 |
| Milk yield, kg/d | 38.1 | 39.0 | 37.8 | 1.37 | 0.78 |
| Milk protein content, % | 3.02b | 3.12a | 3.01b | 0.03 | 0.04 |
| Methionine, µM | 19.5b | 46.4a | 21.3b | 1.84 | <0.001 |
| Total sulphur amino acids (TSAA), µM | 81.3b | 120.1a | 85.0b | 3.75 | <0.001 |
| Slope for TSAA, %TAA –TSAA | – | 0.06908a | 0.01436b | 0.0015 | <0.001 |
a,b Means within rows differ at P < 0.05.