By Jolly Kabirizi
An economically viable livestock sub-sector depends on a reliable supply of replacement stock.
In this context, the calf is important for viable bovine livestock economy and germplasm conservation. Unfortunately, immediate gains from milk often lower the core values of calves in milk and meat value chains due to the stimulation of milk let down, hence the calves are underfed. Most farmers, therefore, resort to restricted milk feeding and grazing as the only available option for raising female calves.
They often cull bull-calves at birth to reduce the cost of feeds and feeding. Advanced dairy economies solve this problem by using commercially formulated milk replacers. The use of complete milk replacers is untenable in developing countries due to technical and socio-economic reasons.
In Uganda, milk production and processing are still lower than the demand for fresh milk. Commercial milk replacers are expensive and their use would not be economically justified for the majority of our dairy farmers who are predominantly small-scale zero-grazers.
Innovative development of early calves weaning formulae as milk replacers would offer a solution to poor calves’ nutrition and household income in the long run.
A cost-effective milk replacer feeding system can increase both the welfare of dairy calves and dairy profitability. Such feeding technologies include the utilisation of locally available feed resources as ingredients in early calves’ weaning diets.
Early weaning reduces the amount of milk consumed by the calves. This, not only releases more milk for human consumption, but also increases cash income for the farmer through increased milk sales, and also reduces the cost of rearing the calves during their nursing period.
Sweet potato vines are one of the many feed resources that have attracted the interest of researchers as a potential feed resource for livestock. Sweet potatoes are widely grown and used for both food and livestock feed.
In Uganda, the vines are utilised as green or ensiled fodder for cattle principally, but also for pigs and other small animals. In terms of chemical composition, the vines have over 18% dry matter and about 18.2% protein (depending on the variety and management practices).
The chemical composition of sweet potato vines is compared to that of milk because they both have high moisture and protein content.
A study was conducted by the National Livestock Resources Research Institute (NaLIRRI) to determine the potential of sweet potato vine-based diets as partial milk substitutes for dairy calves.