Effect of early weaning on postp

The present study was to determine the effect of early weaning (EW) on postpatum reproduction of mother buffaloes and calf growth. An experiment was carried out from February to August 2010 concurrently in 2 localities in Northern Vietnam, viz. Ha Nam and Phu Tho, with very different grazing conditions. In each locality, 12 buffalo-calf pairs were equally allocated into 2 groups of 6 pairs each; in one group calves were allowed to suck their mothers as long as they could according to the traditional practice (the control) and in the other group (EW) calves were weaned at 120 days post calving. In Phu Tho, where green grass was too limited, the calves to be early weaned were given creep feed from one month before weaning.

Analyses of the data pooled from the two localities showed clearly that early weaning improved postpartum reproduction in the mother buffaloes, shortening the period from calving to first estrus (Table 1) and improving conception rate. In Ha Nam, where green grass was abundantly available, weaned buffaloes returned to heat earlier than those in Phu Tho, where the buffaloes had to suffer from harsh grazing conditions (150.5 vs 173.2 days). That is, postpartum resumption of reproduction in buffaloes with early weaning was shorter in the locality with better nutritional conditions.

It was also shown that early weaning had no negative effect on growth of the calf in the long run (Table 1). Although it suppressed calf growth rate to some extent right after weaning, the early weaned calves grew faster later on (Figure 1a,b) as aresult of more time they spent grazing.

Table 1. Effects of early weaning on postpartum reproduction in mother buffaloes and growth of calves at two different localities (Phu Tho and Ha Nam)
Parameter	Phu Tho		Ha Nam		SEM	Significance
Parameter	With early weaning	Without early weaning	With early weaning	Without early weaning	SEM	Weaning	Locality	Interaction
Calving to 1^st estrus (days)	173.2^b	198.0^a	150.5^c	198.7^a	4.8	***	*	*
Calf weight at weaning (kg)	81.92^a	79.17^a	92.67^a	93.00^a	1.36	NS	***	NS
Calf weight at 195 days of age (kg)	117.7^b	117.3^b	146.9^a	145.9^a	2.2	NS	***	NS
Weight gain 75 days of weaning (kg)	35.75^b	38.17^b	54.25^a	52.92^a	1.4	NS	***	NS
NB. Means that do not share a letter are significantly different.

Effect of early weaning on postpartum reproduction in mother buffaloes and calf growth

Cu Thi Thien Thu, Nguyen Xuan Trach and T R Preston