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

Forty-eight pregnant Manchega dairy ewes bearing twins or singles penned in groups of sir during the last 11 weeks of gestation were used to study the effects of forage type (Italian ryegrass hay or alfalfa hay) and number of foetuses tone or two) on voluntary dry-matter (DM) intake and digesta kine tics. Hays were supplemented with 0.6 kg/day of concentrate. When measured directly for group-fed ewes, forage DM intake was affected by forage type ( P < 0.01), whereas litter size had no significant effect. An internal (rume n-undegradable DM) and an external (chromium III oxide) marker were also us ed to determine intake of individual ewes to account for errors in diagnosi ng litter size. Estimated DM intake confirmed the effect of forage type on DM intake and revealed the effect of litter size on food intake (P < 0.05). Forage type also affected chromium III oxide fractional outflow rate and f low of undegradable DM, whereas litter size only had an effect at the end o f 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 si milar DM apparent digestibilities of both hays. Furthermore, litter size af fected DM intake at the end of pregnancy causing an intake decline, which w as greater with alfalfa hay than with ryegrass hay.