Evaluation Of Genes Associated With Mastitis In Crossbred Dairy Cattle

Abstract

Mastitis is a detrimental disease that economically affects dairy farming by reducing milk quality and quantity produced, the sudden death of dairy cows, premature culling of dairy cows before attaining their maximum production ages, and the cost of disease prevention and treatments. In Sub-Sahara Africa, mastitis prevalence among smallholders’ dairy farmers have been recorded to exceed 50 percent, and it has continued to cause significant threats. In East Africa, subclinical mastitis prevalence varies between 16 and 80 percent among smallholders’ dairy farmers. Full udder quarters of 38 lactating crossbred dairy cows were cleaned with 75% alcohol and screened with the California mastitis test (CMT) kit for subclinical mastitis and somatic cell count (SCC). A total of 152 milk samples were collected aseptically from each quarter of 38 lactating dairy cows into screw-capped bottles `for direct microscopic somatic cell count analyses in the laboratory. Ninety-six blood samples from both lactating and non-lactating crossbred cattle were obtained for genomic DNA extractions. The genomic DNA was later run in polymerase chain reactions with two oligo primers of 252 bp (LGB) and 301bp (LTF) for beta-lactoglobulin lactoferrin genes, respectively. Results CMT scores carried out in the farm revealed that 55.01% of udder quarters were negative for subclinical mastitic, 43.99 % trace, and 1.32 % were positive for subclinical mastitis. The Least Square Difference (LSD) for pairwise comparison between CMT scores and lactation stage were significantly different between First and second lactation at 0.25±0.11, the second and third at 0.27±0.0118 at P≥0.05. The means of SCC among the breeds were significantly other at P≥0.05, for Ayshire and Friesian (68.055±18.82 cells/ml); Ayshire and Guernsey (71.976±23.844 cells/ml); Friesian and Jerseys (64.863±21.429 cells/ml); and Guernsey and Jersey (68.78±25.952 cells/ml). Results of PCR-DNA sequenced showed that there were several genetic variations in the nucleotide sequences. These were identified as Single Nucleotide Polymorphisms