EFFECT OF BYMET® SUPPLEMENTATION ON THE PERFORMANCE OF DAIRY COWS

The next research work was presented at the Congress of the American Dairy Science Association (ADSA 2020 Virtual Annual Meeting).

Two trials were carried out in Spanish dairy farms with the objective of evaluating the effects of supplementation of methionine (BYMET®) protected with palm stearin, on the performance and composition of milk.

On farm A, 160 Holstein cows (days in milk 171±106, milk production 36.3±8.2 kg/day), and on farm B, 93 Holstein cows (days in milk 181±143, milk production 38.9±11.6 kg/day) were divided into two homogeneous groups. On both farms, the cows were exposed to 2 treatments for 60 days. Treatments consisted of a control group (CT) that received a basic diet specific to the farm (farm A: 20.1% CP, 30.5% NDF, 1.4 Mcal NEl/kg; farm B: 21.6% CP, 36.5% NDF, 1.1 Mcal NEl/kg; dry matter based), and a group supplemented with BYMET® (BM) that received the same diets, but with less crude protein than the control group (Farm A: 18.4% CP; Farm B: 21% CP) plus 40 g/d of BYMET® (39% Met; providing 16 g of Met / day). In both farms, the protein concentrates used were soybean and rapeseed meal, the decrease in the CP content in the BM groups was established to show the economic benefits of reducing the CP. The cows were fed the ration twice a day.

In farm A, milk production was affected (p = 0.003) by an interaction between treatment and week, cows in BYMET® group produced higher amounts of milk throughout the study (36.8 kg/day), except at week 4, compared to the CT group (36.0 kg/day). In farm B, milk production showed a trend (P = 0.110) in the interaction between treatment and week, BYMET® cows produced an average of 39.8 kg/day and CT cows, 37.8 kg/day. This mean a positive difference of 2 kg/cow/day.

Interactions between treatment and week (P = 0.01 on farm A and B) were observed for fat content (%). This one was similar in both groups on farm A, but was higher in BYMET® cows than in CT cows in farm B. Protein content (%) was affected by an interaction between treatment and week (P = 0.04 in farm A and B), was similar in both groups in farm A, but tended to be lower in BM cows in farm B. However, protein yields (kg/day) were the same in both groups in both farms.

It is concluded that BYMET® can improve the milk production of dairy cows, even those fed TMR with high levels of crude protein.

This work has been carried out within the DECAPVALE project, funded by the Center for Industrial Technological Development (IDI-20160999)