title: Evaluation of fertility in relation to milk production and productivity of Murrah buffaloes.
abstract: Intense selection of buffaloes for milk production at organized herds of the country without giving due attention to fertility traits has lead to deterioration in their performances. The study was initiated to assess the relationship between milk production and productivity with fertility in Murrah buffaloes. In the present study, fertility was defined in terms of pregnancy rate of Murrah buffaloes. Pregnancy rate measures the percentage of non-pregnant animals that become pregnant during each oestrous cycle. Data pertaining to 1224 lactation records of Murrah buffaloes spread over a period 22 years from 1993 to 2014 were analyzed in the study. It was observed that pregnancy rate is negatively associated with 305days or less milk yield (-0.08±0.04) and wet average (-0.12±0.02) and positively associated with life time (0.15±0.03) in Murrah buffaloes. Wet average is defined as average daily milk yield per lactation of Murrah buffaloes. To achieve around 2000kg 305days or less milk yield and 7.5kg wet average, the level of pregnancy rate in Murrah buffaloes should vary between 30 and 50%. The per unit change in pregnancy rate with respect to milk yield in Murrah buffaloes, were studied using regression analysis. The results suggest that increasing hundred kilogram in 305days or one kilogram milk yield per day in 305days, pregnancy rate reduced by 0.9% in overall lactations of Murrah buffaloes. By increasing hundred kilogram life time 305days or less milk yield and one kilogram life time wet average, pregnancy rate of Murrah buffaloes reduced by about 0.2% and 0.34%, respectively. The study quantifies the decline of pregnancy rate with increase of lactation milk yield and wet average in Murrah buffaloes and emphasis the importance of fertility i.e. pregnancy rate in the evaluation and breeding programmes of Murrah buffaloes.
authors.affiliation: Dairy Cattle Breeding Division, ICAR-National Dairy Research Institute, Karnal 132001 Haryana, India. Electronic address: jamunavalsalan@gmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Jamuna
authors.affiliation: Dairy Cattle Breeding Division, ICAR-National Dairy Research Institute, Karnal 132001 Haryana, India. Electronic address: ak_chakravarty@yahoo.co.in.
authors.forename: A K
authors.initials: AK
authors.lastname: Chakravarty
mesh_terms: D000818:Animals; D002020:Buffaloes / Q000502:physiology*; D005260:Female; D005298:Fertility / Q000502:physiology*; D007774:Lactation / Q000502:physiology*; D011247:Pregnancy
keywords: Life time; Pregnancy rate; Production; Productivity; Standardization