Wheat grain as a prepartal cereal choice to ease metabolic transition from gestation into lactation in Holstein cows

Abstract

Wheat grain (WG) is a unique cereal rich in easily fermentable starch and low in cation-anion difference (e.g. 5.3 mEq/100 g). The controlled prepartal dietary inclusion of WG, thus, has the potential to ease adapting the rumen microbes and papillae to the high-starch lactation diets, stimulate feed intake, reduce hypocalcaemia by reducing extracellular alkalinity and a moderate induction of bone resorption, and improve milk yield in periparturient cows. The primary objective was to determine the effects of prepartal feeding of WG compared to barley grain plus wheat bran on metabolic and productive criteria in periparturient Holstein cows. Twenty-four dry cows and 16 pregnant heifers were blocked based on parity and projected calving date and fed a prepartal diet containing either (i) ground WG (18% on a dry matter basis) or (ii) a conventional diet with ground barley grain and wheat bran or control diet, from 28-day prepartum until parturition. All cows were fed the control diet during 21-day postpartum. Prepartal dietary inclusion of WG increased prepartum feed intake, elevated blood glucose and attenuated hypocalcaemia at 7-day prepartum and 1-day postpartum, reduced urine pH, and increased milk fat percent and yield. Blood proteins at 7-day prepartum were higher and placenta tended to be expelled sooner in WG-fed cows than in other cows. Treatments did not affect milk protein, changes in body condition score; total time spent eating, ruminating and chewing; blood levels of urea nitrogen, cholesterol, and phosphorous, fecal pH, and calving difficulty. Therefore, the prepartal dietary use of WG proved effective in the simultaneous improvement of calcium and energy states, and thereby, in easing the metabolic transition from gestation into lactation in Holstein cows.