Voluntary dry-matter intake and digesta kinetics of twin- or single-bearing Manchega ewes given Italian ryegrass hay or alfalfa hay in late pregnancy

Abstract

AbstractForty-eight pregnant Manchega dairy ewes bearing twins or singles penned in groups of six during the last 11 weeks of gestation were used to study the effects offorage type (Italian ryegrass hay or alfalfa hay) and number of foetuses (one or two) on voluntary dry-matter (DM) intake and digesta kinetics. Hays were supplemented with 0·6 kg/day of concentrate. When measured directly for group-fed ewes, forage DM intake was affected byforage type (P < 0·01), whereas litter size had no significant effect. An internal (rumen-undegradable DM) and an external (chromium III oxide) marker were also used to determine intake of individual ewes to account for errors in diagnosing litter size. Estimated DM intake confirmed the effect offorage type on DM intake and revealed the effect of litter size on food intake (F < 0·05). Forage type also affected chromium III oxide fractional outflow rate and flow of undegradable DM, whereas litter size only had an effect at the end of pregnancy by reducing hay intake, rate of passage and digesta flow mainly with alfalfa diets. In conclusion, DM intake, rate of passage and digesta flow was higher with alfalfa hay than with ryegrass hay, in spite of the similar DM apparent digestibilities of both hays. Furthermore, litter size affected DM intake at the end of pregnancy causing an intake decline, which was greater with alfalfa hay than with ryegrass hay.