Investigate the effects of non-genetic factors on calving difficulty and stillbirth rate in holstein friesian cattle using the CHAID analysis; [Genetiksel Olmayan Faktörlerin Siyah Alaca Sığırlarda Güç ve Ölü Doğuma Etkilerinin CHAID Analizi İle İncelenmesi]

A total number of 947 calving records from 613 Holstein Friesian cows raised at a private dairy farm in Kelkit, Turkey, from 2004 to 2006 were used to study the effect of non-genetic factors on calving difficulty and stillbirth rate using CHAID algorithm. The mean calf birth weight was 41.0±0.19 kg. The overall incidence of calving difficulty and stillbirths in the Holstein Friesian herd were 9.1% and 9.4%, respectively. Calf birth weight, birth type and calving season had the greatest impact on calving difficulty. The increase in calf birth weight was associated with a significant increase in calving difficulties (P<0.01). The calving difficulty risk in twins (18.9%) was higher than in singleton calves (5.0%). The main environmental variables affecting the stillbirth rate were parity number, calf birth weight, sex of calf, calving season and calving difficulty. Parity number was statistically the most relevant factor affecting the stillbirth rate, which was also higher in primiparous (18.7%) than in multiparous cows (5.4%). As the calf birth weight increased, a significant increase was also in the stillbirth rate (P<0.01). The stillbirth rate in winter (19.7%) was higher than in other seasons (3.6%) (P<0.01). Calving assistance was associated with an increased risk of stillbirth (P<0.05). As a result, calf birth weight, birth type and calving season had the greatest impact variables on calving difficulty, however, parity, calf birth weight, sex, calving season and calving difficulty were the most effective variables on stillbirth in Holstein Friesian Cattle.