Recent advances in research on draught ruminants

Abstract

A feeding system, draught cows, disease/work interactions and animal power introduction in a farming system are reviewed. A new feeding system for draught animals is described which enables feed requirements and the effects of work on liveweight and milk yield to be calculated. Recent data on the energy cost of walking are appraised. Research on working cows, mainly in Ethiopia, has shown that undernutrition has a greater effect on milk yield than work, which has a transient effect. The length of the post-partum anoestrous period increases with decreasing body condition. Body weight loss increases with increasing work load. It is suggested that dairy cows delay conception by 1 day for every day of work done. Work has little effect on feed intake or digestive parameters. Although it is associated with an overall increase in feed intake of cows, even of unsupplemented forage diets, the increase is not sufficient to meet all the extra energy needs for work. Feed intake of working and non-working cows increases during lactation. Disease limits the working capacity of draught animals and work can exacerbate disease. These effects were investigated using Trypanosoma evansi in Indonesia and T. congolense in The Gambia. In both studies, infected animals were able to do much less work than non-infected ones and the severity of the effect depended greatly on the strain of trypanosome used. In general, increasing the plane of nutrition did not ameliorate the effects of the disease, nor in the Gambian study did it prevent loss of appetite in infected animals. The technical and agronomic innovations necessary for the introduction of animal power into an inland valley region of central Nigeria are described and some of the sociological implications discussed.