Abstract

Providing additional energy to dairy cows in early lactation can increase energy intake, and improve production; however, different energy types may elicit different types of responses. The current study assessed the effect of supplementary feeding of starch, fibre, or sugar on milk and milk component yield. Sixty-eight dairy cows, due to calve over a 21-day period, were randomly assigned to one of four treatments at parturition (n = 17). Treatments consisted of a pasture-only control and pasture with starch, fibre or sugar based supplements. Supplements were formulated using the Cornell Net Carbohydrate and Protein System v6.1 and fed at an isoenergetic rate to supply sufficient metabolisable energy and protein to support a target of 30 kg of potential milk production, assuming cows would consume 13 kg of pasture DM/day; 11 MJ ME/kg DM. The study ran for eight weeks, and data were analysed on a week of lactation basis. Relative to the control, milk and milk protein yields were higher for the starch- and fibre-based supplements, but similar for the sugar (P <0.01). Protein yields were highest in cows supplemented with starch (P <0.001), while fat yields were numerically highest in cows supplemented with fibre. These data confirm that the form of carbohydrate fed affects the types of responses seen when supplementing concentrates in early lactation.

RJ, Higgs, AJ Sheahan, K Mandok, and JR Roche

Proceedings of the New Zealand Society of Animal Production, Volume 71, Invercargill, 23-27, 2011