Effects of Breed, Age and Body Condition Score on the Biochemical and Hormonal Parameters of Three Cattle Breeds from Chad (Arab, Kouri and Toupouri)

Background: This study was conducted to evaluate the biochemical and hormonal parameters of three cattle breeds in Chad (Arabian, Kouri, and Toupouri cows) in order to enhance the productivity of the cattle sub-sector in Chad while conserving local genetic resources. Methods: A total of 166 cycling cows and 40 pregnant cows were used. Breed identification was based on phenotypic characteristics. The age of each animal was determined by simultaneous analysis of dentition and horns. Body condition score (BCS) was determined before slaughter. The blood samples were collected during slaughter and centrifuged. The resulting serum was then analyzed to determine serum urea concentrations, total cholesterol, phosphorus, and total protein colorimetrically using a Lab Max Plenno automated chemical analyzer with commercial reagents. Hormone levels (FSH, LH, P4, and estradiol) were obtained using the ELISA method. Calcium, phosphorus, and urea levels were obtained using complexometry and flame photometry techniques. Results: Results revealed that the number of pregnant cows observed during the study period was 18.93%. Cows with low (BCS = 1 - 2) and medium (BCS = 3) BCS represented more than half of the cows of the study. Protein and cholesterol levels were in general higher in Kouri and Toupouri cows compared to Arabian. Phosphorus levels were high in young cows. Regardless of the breed, hormone levels were generally higher in young cows (3 - 5 and 6 - 9 years); although some older cows were an exception. Among the different BCS groups, lean Arabian cows (BCS = 1 - 2) and cows with average body reserves (BCS = 3) had significantly higher calcium levels. Conclusions: This study indicates that young animals (3 - 5 years) with average BCS of 3 could be the best choice to use when doing selection of the local cattle to enhance reproduction.Subject AreasAnimal Behavior