On-farm cow-calf performance in response to pre- and post-partum concentrate supplementation in South Central Coastal Vietnam

Supplementing cows with concentrate feeds in the last trimester of pregnancy and during lactation is important in maintaining cow body condition, positive energy balance and preventing the mobilisation of stored fat. However, there is a lack of information about the effect of supplementary feeding of beef cows during pre and post-partum periods on cow-calf performance in South Central Coastal Vietnam. Therefore, the main objective of this study was to evaluate the effect of pre- and post-partum supplementary feeding on cow-calf performance in an on-farm experiment.

Twenty crossbred cows in the third trimester of pregnancy were randomly allocated into four pre- and post-partum treatment groups comprising: 1) Control diet only; 2) Control diet pre-partum and improved diet post-partum; 3) Improved diet pre-partum and control diet post- partum; and 4) Improved diets only. The control diet was a mixture of maize powder and rice bran offered at 0.25% of body weight (BW) pre-partum and 0.35% of BW post-partum. The improved diet was a mixture of maize powder, rice bran, peanut cake and cassava powder offered at 0.35% of BW pre-partum and 0.5% of BW post-partum.

The improved diet had a significant (P<0.05) positive effect on calf birth weight, body length, and chest girth, but not at 90 days. There was a significant effect of diet on average cow body weight, body condition score (BCS) and calving to conception interval (CCI). However, the timing of feeding the concentrate (pre- or post-partum) had no effect. The CCI was longer for cows fed the control diet (212 days) than for cows supplemented pre-partum (176 days). Cows fed post-partum had the shortest CCI (Av. 144.5 days). It was concluded that pre- and post-partum supplementation improved cow-calf performance and induced early cyclicity thereby shortening the interval from calving to conception and overall reproductive performance under on-farm conditions.