Some animal and feed factors affecting feed intake, behaviour and performance of small ruminants

The overall objective of this thesis was to assess the effect of some animal and feed factors on feed intake, behaviour and performance of small ruminants. The experiments were carried out at the Goat and Rabbit Research Centre in Northern Vietnam. The effects of two physical forms of whole sugar cane (WSC) and four different levels of WSC offered with or without concentrate on feed intake, selection and eating behaviour of weaned goat kids and lambs were studied. Both kids and lambs fed with WSC chopped in slices (1-3 cm) had higher daily dry matter intake (DMI) than those fed WSC chopped into 20 cm lengths (208 g versus 173 g/day) and eating time was reduced as chopping length of the WSC decreased. Kids had higher DMI of WSC than lambs (214 g versus 166 g/day) and spent more time eating. The DMI of lambs was highest when WSC was offered at 6% of body weight, while DMI of kids was not significantly changed as the amount of WSC offered was increased. Adding concentrate as a supplement had no effect on the DMI of WSC, only on total DMI. Of the presentation methods tested hanging the foliage from the wall of the pen or tying in the trough resulted in higher intake, while chopping or stripping the leaves gave lower intakes. The highest DMI (637 g/day) was obtained with Jackfruit (JF, Artocarpus heterophyllus), a moderate DMI (247 g/day) of Flemingia (FM, Flemingia macrophylla) and lowest intake (138 g/day) with Acacia (AC, Acacia mangium). The DMI of goats fed mixtures of JF+FM or JF+FM+AC was higher than of those fed mixtures of JF+AC or FM+AC. The DMI of kids fed mixtures of JF+FM or FM+AC was higher with the hanging than with the tying method, while this was the opposite case for the mixtures of JF+AC or JF+FM+AC. Adding bamboo charcoal to the diet increased dry matter (DM), organic matter (OM) and crude protein (CP) digestibility and nitrogen retention. The highest DM, OM, CP digestibility and N retention were obtained in goats fed 0.5 or 1.0 g charcoal/kg body weight /day. The goats given the diet with bamboo charcoal grew faster than those given the diet without bamboo charcoal. The highest total DMI was obtained by goats fed wilted Acacia, significantly different from fresh and dried Acacia. However, the weight gain of the goats was similar among the three processing methods of Acacia. Keeping goat kids and lambs in five different group sizes of 1 to 5 animals per pen showed that the kids fed the diet consisting of JF had a higher total DMI than lambs fed the same diet, while there was no difference in total DMI between kids and lambs fed a diet consisting of a mixture of foliages from JF+AC. The feed intake linearly increased with increasing number of animals in the pens, but more aggressive behaviour was recorded in pens with higher numbers of animals. The weight gain was higher for the lambs compared to the kids, but was similar for animals in the group size of 1 or 5 animals.