Parametric Estimation of Factors Associated with Prediction of Calving in Surti Buffaloes Using Ordinal Regression
L. M. Sorathiya V. B. Kharadi A. P. Raval K. H. Sadharakiya K. K. Tyagi M. A. Katariya
Vol 9(1), 231-237
Accurate prediction of calving is a key factor for profitable livestock farming. A depression on rump near sacrum due to relaxation of sacro-sciatic ligament is a characteristic sign of animal approaching calving. Present study was an effort to measure the depth of depression on rump region and vulvar zoometry in 44 pregnant Surti buffaloes. All the buffaloes were measured for zoometry on alternate days for last 2 months of gestation. The date of calving was considered as day 0. The observations taken before 45 days prior to calving were considered as normal observation found in non-pregnant buffaloes. The observations taken 45, 30, 15, 10, 5, 2 and 0 days prepartum were selected for analysis. The mean depth of vulva was 1.80, 2.06, 2.70, 3.04, 3.44, 3.66 and 4.11 cm before 45, 30, 15, 10, 5, 2 and 0 day, respectively. The angle lateral to sacral crest was found to be reduced when animal approaches calving due to increase in depth in depression on rump. It was about 170° before 45 days of calving and 155° before 10 days of calving. When it decreases to 150° we can say that the calving may occur within two days. The depression of rump between anterior sacral crest to pin bone (D2) was 2, 2.11, 2.88, 3.18, 3.66, 3.89, 4.37 cm before 45, 30, 15, 10, 5, 2 and 0 days, respectively. The depth D2 when exceeds 3.5- 4 cm is suggestive of calving within 2-5 days. The ordinal regression analysis of all predictors with six pre-calving groups (threshold) revealed that depth of vulva and angle on rump were significantly associated in prediction of calving day with 0.75 pseudo R2.
Keywords : Buffalo Calving Ordinal regression Pregnant Prediction Sacro-sciatic ligament Vulva Zoometry
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