Development of breeding strategy based on body coloration and phenotype in Holstein Friesian crossbreds for sustainable milk production

Abstract

The aim of this study was to implement a sustainable breeding strategy based on phenotypic grading. Holstein Friesian crossbreds were categorize depend- ing on white coloring in body parts, hump status, known genrations derived from controlled breeding and recording, and to reveal the effects of these fea- tures on milk production. Data of peak milk production and morphological characteristics were collected on 51 Holstein Friesian crossbred cows after primary sorting from three districts (Sirajganj, Chittagong and Mymensingh) of Bangladesh. The animals were graded according to the white coloring pattern (absent or present) in horn, eyelid and eyelash, muzzle, hoof, tail switch, and the presence of a hump. It was observed that the presence of white color (18.86±1.01 to 22.00±1.57 L) in different body parts of Holstein Friesian crossbreds were significantly (p<0.001) associated with higher milk production compared to the absent group (8.95±1.62 to 13.84±1.21 L). Aver- age peak milk production for humpless cows was 15.89±1.16 L, compared to 4.8±0.58 L for humped cows. The grading of cows based on white coloring and hump status showed significant differences (p<0.001) in milk produc- tion, but the production between medium and higher graded cows were not varied significantly. White color was not found in all studied body parts for lower graded cows while its frequency increased in medium graded (up to 75%) and almost full in higher graded cows except eyelid and eyelash (66.7% white). To prove the above findings, another 10 Holstein females with known genetics of exotic inheritance were evaluated for the same clarifications as reference population and similar trends were revealed with respect to the increasing of white color frequency from the F1 generation (66.7% in hoof and 50% in tail switch) to F2 (25% in horn, 25% in muzzle, and 75% in hoof and tail switch), including 100% humpless characters. It is concluded that milk production varied according to coloring patterns in different body parts and three selected grades and these phenotypic grading-based planned breed- ing strategies could retain the exotic inheritance level in Holstein Friesian crossbreds.