Multiple births were induced in 20 hinds subjected to a progesterone plus gonadotropin treatment to advance the breeding season by about 4 to 5 weeks. In total, over 2 years, 92 hinds were treated and run with melatonin-treated stags. Of the 59 hinds that calved to the induced oestrus, 39 produced single calves, 19 produced twins and one produced triplets. Birth weight, gestation length, perinatal mortality and growth rate to weaning at ca. 20 weeks of age were compared for singles and twins. There was a significant effect of birth type on birth weight with twins being proportionately 0·30 lighter than singles (6·27 and 8-94 kg; P < 0·001), with a significant interaction between the birth weight of a calf and the sex of its co-twin (P < 0·05); males born as co-twins to females were proportionately 0·18 heavier than their co-twin females (P < 0·06), while in contrast twin male sets were substantially lighter than twin female sets. Gestation lengths were similar for both singles and twins, with significant negative relationships between gestation length and birth weight for both singles and twins, with a 2-day decrease in gestation length for a 1-kg increase in mean birth weight. There was a strong quadratic relationship between perinatal survival and birth weight; the expected mortality rates at 5, 8 and 11 kg birth weight derived from the relationship were 0·39, 0·11 and 0·39 respectively, indicating reduced probability of survival at both low and high birth weights. The regression relationships between weaning weight or growth rate to weaning and birth weight indicate that at the same birth weight, twin-reared calves were about 5 kg lighter than singles at 20 weeks, while an extra 1 kg weight at birth was associated with an extra 2 kg weight at 20 weeks.

Seventy-two Landrace pigs were used to study the effects of dietary crude protein concentration (197, 168 and 137 g/kg air dry meal), sex, type and live weight on the whole- body (gut content included) amino acid composition of growing pigs. Boars and gilts from two types (lean and obese) slaughtered at 20, 30 or 90 kg live weight were used. Mean whole-body amino acid concentrations were: lysine 63·4; methionine 21·8; cystine 15·8; threonine 35·1; leucine 67·7; isoleucine 28·0; valine 40·5; phenylalanine 35·5; tyrosine 24·6 and histidine 26·8 g/kg protein. Dietary protein concentration had no effect on body amino acid composition. Boar values tended to be higher than those of gilts but there were no significant differences. Pigs of the obese type also tended to have higher values than lean pigs, with significant differences obtained for methionine, cystine, leucine, and isoleucine. Apart from cystine, live weight had no effect on whole-body amino acid composition, Cystine content however, decreased highly significantly from 17·1 g/kg protein at 30 kg live weight to 14·3 g at 90 kg live weight P (P < 0·001). When compared with the suggested ideal pattern for essential amino acids leucine and histidine values are higher and isoleucine slightly lower, with no conclusive indication on methionine and cystine.

One group of five oxen in the Koshi hills of Nepal ate rice straw plus 4 kg fresh weight per day of the fodder tree Ficus auriculata. Another group of five oxen ate only rice straw. Calculations showed both diets were low in rumen degradable nitrogen (RDN). The animals which ate the tree fodder had a higher dry matter (DM) intake than those eating rice straw alone. Both groups consumed less food and lost weight in weeks when they worked for 5 to 6 h (walking 16 km, climbing 600 mlday) than in weeks when they were not walking. No significant differences in digestibility of food were seen. In the weeks after work the group receiving the tree fodder regained weight, while cattle eating only rice straw remained at a lower weight. Supplementation of rice straw with tree fodder rather than expensive concentrate may be acceptable when feeding working oxen although both diets are likely to be deficient in RDN.