Leucaena leucocephala as a feed for dairy cows. Direct effect on reproduction and residual effect on the calf and lactation

Abstract

Leucaena 1ericocc.phala was given for periods of 30 days to 14 months to nonlactating dairy cows in all stages of the reproductive cycle. Similar cows were fed on lucerne for comparison. Leucaena did not affect oestrous cycle length, conception rate, or gestation length. Feeding leucaena to heifers pre partum did not affect the mean yield and composition of milk over the first 9 weeks of lactation when a normal milking ration was used post part~lm, but the shape of the lactation curve was slightly flattened. Some mild incoordination and nervous symptoms occurred briefly during gestation in some cows on leucaena. Mild depilation was seen in several cows and quite extensive depilation in one. Calves from cows fed on leucaena had a significantly lower mean birth weight (19.6 kg) than control calves (25.8 kg) and one cow fed on leucaena had a still-born calf. Calf thyroid glands were enlarged and plasma protein-bound iodine levels elevated, but thyroid gland histology was normal. Basal metabolic rates and growth rates of the calves were the same in the two groups.