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By-pass protein in dry cow diets proven to boost milk yields

9 March 2017

Farmers are being urged to plan dry cow rations with care, as investing in the dry period is critical to reaping the benefits in the next lactation.

“Post-calving, cows often receive close attention and top quality diets, yet pre-calving, it’s easy to underestimate the influence the ration can have on the proceeding lactation,” says Bethany May, Trident Feeds ruminant nutritionist. “It’s critical that dry cows receive enough quality protein in the diet, when fed with a silage or straw base, to maximise outputs when entering lactation.”

Miss May explains how feeding a quality rumen by-pass protein in the diet of dry cows has been proven to improve milk yields, but stresses the importance of source.

“There are two types of protein available to the cow; rumen degradable protein (RDP) and digestible undegraded (DUP) by-pass protein. RDP is the protein supply available to the rumen microbes, whereas by-pass protein is protein which isn’t digested in the rumen, and is utilised more efficiently in the intestines.

“During the last few weeks of pregnancy and at calving, the cow’s requirement for protein increases, particularly with growing heifers, and dry matter intake will reduce. Consequently, this reduces the amount of protein available to boost colostrum production and udder preparation or growth.

“By supplementing the diet pre-calving with a source of by-pass protein, this repletes body protein reserves, eases the transition from calving to lactation without putting too much reliance on adequate rumen function to provide metabolisable protein.

“It also stimulates intakes in early lactation and improves milk yield. Several trials at UK universities (SRUC 1992-1994, Wye 1994) have shown supplemental by-pass protein increased milk protein yield and early lactation dry matter intakes (Moorby et al, 1996).

“A proven cost-effective source of by-pass protein is Trident’s SoyPass, which is produced using a unique patented process which doubles the amount of by-pass protein in soya bean meal,” Miss May adds.

Inclusion of SoyPass acts as an ‘insurance’ against drastic reductions of body protein reserves, particularly when feeding poorer quality silages, which helps minimise loss of body condition post calving. It helps maintain optimum milk yields, but importantly not at the expense of fertility.

“Trials in Mecklenburg, Germany, replaced soya bean meal with SoyPass. Cows fed SoyPass during the dry cow period, had an increase in milk yield of 1.4kg per day in the first five months of lactation, so the benefits of the addition of SoyPass were seen through increased milk output,” adds Miss May.

“Protein plays a vital role in the transition of dry cow to lactation, so inclusion of supplementary by-pass proteins in the diet will ensure there are sufficient levels to meet the cow’s needs at calving ready for early lactation.”

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