Effect of Work Stress and Supplementary Feeding on Body Conformation, Ovarian Activity and Blood Parameters in Mashona Cows in a Smallholder Farming System

The objective of this study was to determine the effect of draught stress on certain haemograms and ovarian activity and the influence of dietary supplementation on the negative effects of draught in cows. Blood parameters and ovarian activity were assessed in supplemented non-working (SNW), supplemented working (SW) and non-supplemented non-working (NSNW) cows. Body weights and body condition scores were recorded fortnightly. Blood samples were collected through jugular venipuncture in December, February and April to determine the contents of haematocrit, erythrocyte, haemoglobin and white blood cells. Ovarian palpations were carried out in October, January and April. The SW cows maintained body weights (p>0.05) during the monitoring period whereas both SNW and NSNW cows gained (p<0.05) body weights. Body condition scores were similar between SW and NSNW cows. Cows in the NSNW group had lower (p<0.05) haematocrit concentrations in April than both supplemented groups. In December, erythrocyte concentrations were similar (p>0.05) among all treatment groups. Haemoglobin concentrations were higher (p<0.05) in SW and SNW cows in February and April than in December. The SW cows had higher leucocyte contents (p<0.05) in February than the other groups of cows. All treatment groups showed similar (p>0.05) ovarian activity in January. However, the NSNW group showed a lower proportion (p<0.05) of cows that exhibited normal ovarian activity in April. The results suggest that dietary supplementation of cows increases haematocrit and haemoglobin contents. In addition, supplementary feeding during the period of draught power provision maintains ovarian activity in cows.