Discipline: feeding; Keywords: PUFA, pregnancy, culling, BCS, digestibility, microbial protein
Research in the past 50 years has shown that the general health of dairy cows can be improved by higher post-ruminal delivery and absorption of poly-unsaturated fatty acids (PUFA), especially omega-3 (n-3) acid. Since flaxseed contains a high concentration of n-3, the objective of the authors cited below was to evaluate the effects of feeding the flaxseed-based supplement LinPro on the production and health of mid-to-late lactation multi-lactation Holstein cows.
Three pens of about 365 cows were fed diets formulated to contain 0g per kg (NoLin), 25g per kg (LoLin) or 50g per kg (HiLin) dry matter (DM) of LinPro in a design that rotated cows and diets among pens monthly. Individual body condition (BCS) was scored, and milk yields recorded monthly for four months after assignment to treatment at 155 ± 0.10 days in milk . In addition, DM intake, microbial protein (MP) outflow from the rumen (using the urine allantoin-based method) and digestibility, total and of constituents, were measured.
Whereas MP outflow was lower and estimated whole digestive tract apparent digestibility of NDF tended to be higher with LinPro feeding, DM intake was unaffected. Milk yield and milk components showed interaction affects with DM intake, which suggest biologically small differences in responses to the three diets as DM intake increased. Rapid and substantial BCS losses for the LoLin group in the first 30 days of LinPro feeding was regained in the next 50 days The lower proportion of cows culled for mastitis in both LinPro fed groups suggests improved health of cows fed LinPro. Feeding LinPro at both levels transferred dietary n-3 into milk, with marked decreases in the n-6 to n-3 fatty acid ratio, thereby improving the healthfulness of the milk fat to consumers.
In conclusion: Feeding the flaxseed supplement at the level of 25g per kg of dietary DM, but not at 50g per kg dietary DM, had net benefits in mid-to-late lactation cows, due to similar DM intake and milk production, improved general health (by reduced milk somatic cell counts and culling for mastitis), increased milk fat and protein levels, and a higher nutritional value of the milk to consumers as suggested by research of health impacts of dairy products in human diets.
Swanepoel, N. & Robinson, P.H., 2019. Impacts of feeding a flax-seed based supplement on production and health of mid through late lactation multiparous Holstein cows on a commercial dairy farm. Animal Feed Science and Technology 258, 114318.