Genetic analysis of persistency indices of milk yield in Jersey crossbred cattle

Abstract

The study reported in this Research Communication was conducted to estimate genetic parameters for different lactation persistency indices and their association with reproductive traits in Jersey crossbred cattle. Data on lactation traits (part lactation yields and 305-days milk yield) comprising all lactations as well as reproductive traits viz. calving interval, conception rate and gestation length of 378 Jersey crossbred cattle, maintained at National Dairy Research Institute, Kalyani, West Bengal, India, were collected over a period of 35 years (1982–2016). Five lactation persistency indices of animals (P21, P31, P32, P4 and P5) were calculated using ratio method. A total of six different animal models, ignoring or including maternal genetic or permanent environmental effects, were fitted for all persistency traits. The best model was chosen after testing the improvement of the log-likelihood values. The estimates of direct heritability were low in magnitude and ranged from 0.02 to 0.14 for the studied traits under the best fitted animal model. The permanent maternal environmental (c2) effects of different lactation persistency indices accounted for 2–9% of the total phenotypic variance in this study. Estimated genetic correlations of lactation persistency indices with all studied reproductive traits were low to moderate and negative (−0.11 to −0.68), except for calving interval. Phenotypic correlations of lactation persistency measures with studied reproductive traits were low (0.01 to 0.15). The low heritability estimates of all the persistency indices indicate some limited scope of genetic improvement of lactation persistency of animals through selection under the prevailing management conditions.

Effect of a Garlic and Citrus Extract Supplement on the Lactation Performance and Carbon Footprint of Dairy Cows under Grazing Conditions in Chile

“…The ability of cows to sustain a high milk production rate for longer periods during lactation is an economically important trait for a profitable dairy enterprise. A significant effect of parity on lactation persistency has been reported, with cows in first parity displaying a higher lactation persistency compared with other cows [ 39 ]. The presence of a large number of secretory cells in the mammary glands of first-time lactating cows was cited as an explanation for their higher lactation persistency compared with subsequent lactations.…”

Genetic aspects of Wood's lactation curve parameters in Jersey crossbred cattle using Bayesian approach

“…Hence, dairy animals maintained in this farm are exposed to a wide range of climatic changes round the year. The managemental practices of animals in this herd have been described by Koloi and Mandal (2020). Due to non-existence of multiple Jersey crossbred herds in India, data on lactation traits from multiple herds over this period are not available (Koloi and Mandal, 2020).…”

Evaluation of milk persistency of second lactation in several grading of Jersey x Red Sindhi crossbred cows

“…The persistency as a flat curve for daily milk supply throughout the lactation period that does not fall soon after the peak. According to (Kole, et al 2018)) [9] cows with high persistency produce more milk at the conclusion of the lactation period and less milk at the beginning. Environmental variables that affect lactation persistence include diet, gestation, animal calving season, herd management, genetic group, sire impact, and lactation number.…”