Study on abnormal lactation length in crossbred cattle
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Date
2020
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Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana
Abstract
The present study was conducted on 1001 crossbred cattle, sired by 146 bulls over a period of 30 years for abnormal lactation length. The overall mean for lactation length, dry period, service period, calving interval, peak yield, 305 days milk yield, lactation milk yield, days to reach peak yield, average fat percentage, 305 days fat yield and lactation fat yield is found to be 330.869 ± 3.022 days, 91.133 ± 2.237 days, 189.782 ± 3.453 days, 460.821 ± 3.51 days, 20.022 ± 0.321 kg, 3310.23 ± 32.897 kg, 3862.17 ± 44.818 kg, 44.425 ± 0.692 days, 3.395 ± 0.031%, 106.523 ± 1.502 kg and 127.51 ± 2.122 kg respectively for the herd in an all-inclusive data. 72.64% of total lactations fell in the normal lactation length range (180-483 days). 5.67 %, 7.36%, 8.86% and 6.02% of lactations comes under short lactation length, prolong lactation length, extremely short lactation length and extremely prolong lactation length respectively. Parity, Period of calving, Season of calving, Abortion, Metritis, Repeat breeding, Foot and Mouth Disease, Brucellosis, Fever, Diarrhoea, Udder swelling, Mastitis, Lameness and weakness were significantly (P⠤0.05) affecting lactation length. Mastitis and Lameness at early lactation and Fever, Diarrhoea, and Weakness at late lactation significantly (P⠤0.05) affected lactation length. Incidences of retention of placenta, Fever, Udder swelling, mastitis and diarrhoea are identified as potential risk factors (P⠤0.05) for SLL and presence of repeat breeding, retention of placenta, foot and mouth disease, mastitis, metritis and diarrhoea as risk factors for ESLL. Presence of dystocia, metritis, lameness and parasitological diseases were identified as risk factors (P⠤0.05) for PLL whereas retention of placenta, dystocia, and metritis were identified as risk factors for EPLL. The alteration of lactation lengths affected all important traits of crossbred cattle in current as well as next lactation. The estimates of heritability, repeatability and genetic correlations improved on standardization of the data. The sire rankings based on breeding value estimates and sire rank correlation show extensive difference between all-inclusive and standardized data.
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T1843