Weaning rate and weaning weight are key indicators of cattle herd productivity and drivers of herd profitability. This is applicable at both a national and household herd level and improving these indicators will result in an increase in herd size, productivity and profitability. Therefore increasing weaning rate and weaning weight align with the Government of Indonesia’s goals to increase the size and productivity of the cattle herd in Indonesia as well as increasing cash flow for smallholder cattle farmers.
The experiment was conducted at the University of Mataram, Teaching and Research Farm, Lingsar, Nusa Tenggara Barat province in Indonesia (8°34'20.15"S, 116°10'59.89"E) between November 2013 and November 2016. The objective of this project was to investigate the effects of maternal nutrition during pregnancy and lactation on the long-term growth rates of Bali cattle. Bali cows were fed diets to establish and maintain divergence in body condition [moderate (Mod_) vs high (High_) body condition score (BCS)] throughout pregnancy and lactation. Milk production and calf growth were monitored until weaning at six months of age, and calf growth was monitored from weaning through to 15 months of age.
Cows that were in High_BCS during lactation produced twice as much milk as cows that were in Mod_BCS (2 vs 1 kg/day) throughout lactation resulting in calves that grew twice as fast (0.4 vs 0.2 kg/day) and were weaned at a heavier liveweight at six months of age (80 vs 40 kg). This 40 kg difference in liveweight persisted through to 18 months of age when calves were offered the same diet after weaning. The results clearly demonstrate the relationship between cow body condition (energy reserves), milk production and pre- and post-weaning calf growth and provide a simple, specific extension message for extension agencies and farmers.
While the current study was not designed to investigate calf survival, it is likely that calves with higher growth rates prior to weaning will have higher survival rates through to weaning, resulting in an increased number of larger calves at weaning and through to at least 18 months of age. While the project demonstrated the long-term benefits of increased weaning liveweight on subsequent growth rates of Bali cattle, which was achieved by feeding tree legumes and maize grain, the most biologically and economically efficient method to achieve this outcome was not tested. The management system used to increase the number and liveweight of weaners will largely depend on the quantity and quality of feedstuffs available to farmers which would influence their decision to supplement the lactating cow to maintain a high body condition (with a higher ME requirement), supplement the suckling calf to increase nutrient supply (with a lower ME requirement) or to implement early weaning, either alone or in conjunction with the above supplementation strategies. In addition alternative feeds to those used in the current experiment need to be identified and tested with farmers.