The effect of contrasting silages offered in mid and late pregnancy on the performance of breeding ewes

Abstract

ABSTRACTEarly-cut, precision-chopped (EP) and late-cut, flail-harvested (LF) silages were offered ad libitum to breeding ewes during mid and late pregnancy in two experiments. Silages offered in late pregnancy were factorially arranged with silages offered in mid pregnancy giving four silage treatments. Voluntary drymatter intake, ewe weight change, lamb birth weight and blood levels of 3-hydroxybutyrate (3-OHB) and non-esterifiable free fatty acids (NEFA) were measured. The intake of LF silage was proportionately 0·61 and 0·72 of that of EP silage in mid and late pregnancy respectively. While type of silage given in mid pregnancy did not affect the mean silage intake in weeks 15 to 20 of pregnancy, the rate of decline in intake was higher and the intake during week 20 of pregnancy was lower following the feeding of EP silage in mid pregnancy. Despite a considerably lower level of body reserves associated with LF silage given in mid pregnancy, there was little effect on levels of 3-OHB or NEFA in late pregnancy or on lamb birth weight.