Effect of bovine recombinant somatotropin protein on milk yield in Hanwoo

Abstract

ChungNam National UniversityReceived on 17 October 2011, revised on 27 October 2011, accepted on 18 December 2011Abstract : This study was carried out to increase the breeding rate using sustained recombinant bovine somatotropin (bST) and examine the reproductive disorder and disease prevalencies of cow and calf, respectively. Sixty cows were allotted randomly to three groups in randomized complete block design; (1) No treatment, (2) 500 mg bST two times + 250 mg bST SC injection five times from 3 weeks before to 9 weeks after parturition every two weeks, (3) 500 mg bST two times before 3 weeks parturition + 250 mg bST SC injection three times from five to 9 weeks after parturition every two weeks. Developmental data of birth weight, weaning weight, total gain and average daily gain in control was 22.9±3.45 kg, 88.0±11.13 kg, 65.1±9.74 kg and 0.54±0.08 kg, respectively. There is no significant difference between Group 1 and 3 in the examined factors. However, there is significant difference between Group 1 and 2 in the birth weight (24.4±2.88 kg), weaning weight (101.0±11.77 kg), total gain (76.7±7.9 kg) and average daily gain (76.7±7.9 kg). Total gain was showed higher in Group 2 and 3 than Group 1 in the >2nd parity, and in Group 2 than Group 1 and 3 in the 1st parity. There is no significant difference in the BCS, no return days and disease occurrence of cow and calf by bST treatment. Number of service per conception was slightly increased in the Group 3 compared to Group 1 and 2. To increase the breeding ability of Hanwoo, it is recommended that 500 mg bST two times + 250 mg bST injection five times from 3 weeks before to 9 weeks after parturition every two weeks. Key words : Recombinant bovine somatotropin, Korean native cattle, Weaning weight*Corresponding author: Tel: +82-31-299-2016E-mail address: jswoo631@korea.kr