Studies on treatments results from cows with ovarian disorders in relation to year and season

Abstract

The studies were performed in the dairy farm from Dancu Research and Development Station for Cattle Breeding, Iaşi, Romania, for a period of 5 consecutive years (2007- 2011), an effective annual rolled of 450 cows Bălţată cu Negru Românească (Romanian Black Spotted) breed.The experimental groups were composed of cows with anoestrus in 60 days postpartum interval, diagnosed by rectal examination with various ovarian disorders: persistent corpus luteum - group E1-162 cows and luteal cysts- group E2-138 cows. The treatments according to diagnosis were applied: PGF2α-,500 mcg/cow- group E1 and Gn-RH, (Receptal, 5 ml/cow-group E2). In relation to the year in which treatments were applied some variations in reproduction indices were found. Regarding to average intervals from treatment to first insemination and from treatment to conception respectively, significant differences were not found. Regarding to average conception rates after treatments, significant differences were found: in E1group, conception rate at the first insemination was 30,9% (with annual variations between 15,0% in 2008 and 41,1% in 2009) (p<0,01); per total insemination was 64,42 % (with annual variations between 44,7% - 2011 and 76,9% - 2007) (p<0,001) and pregnancy index was of 2,4 (with annual variations between 1,9 - 2009 and 2,8 – 2008); in E2 group, conception rate to first insemination was 25,96% (with annual variations between 16,66% - 2011 and 40% - 2010) (p<0,01); per total insemination was 77,88% (with annual variation between 52,17% - 2008 and 85,0% - 2010) (p<0,001) and pregnancy index of 2,4 (with annual variations between 2,1 - 2007 and 2,6 - 2008 and 2009). In relation to season in which treatments were applied, we found different variations in conception rates: in group E1, the average conception rates at the first insemination were between 24,24 % (autumn) and 40,7% (summer) (p<0,05) and per total inseminations between 75,0% (spring) and 85,71% (autumn) (p<0,05); in group E2, the average conception rates at the first insemination were between 5,3% (summer) and 48,5% (spring) (p<0,001) and per total inseminations between 68,4% (summer) and 81,8% (spring) (p<0,05). We believe that annual and seasonal variations found in this work are due to some deficiencies of management system in dairy farms, such as the stalls prolonged maintenance and lack of active movement in the cold season, inadequate microclimate of shelters, heat stress and deficiencies in cows feeding , especially those with higher milk production.