Genetic Analysis of First Lactation Monthly Test Day Milk Yields, Peak Yield and 305 Days Milk Yield in Murrah Buffaloes

Background: The estimates of genetic parameters are useful in determining the appropriate method of selection that could further be implemented in the breed improvement programmes. The present study was, therefore, conducted to estimate the genetic parameters (heritability, genetic and phenotypic correlations) for monthly test day (TD) milk yields, peak yield (PY) and first lactation 305 days milk yield (FL305DMY) in Murrah buffaloes.Methods: Paternal half-sib correlation method was carried out by least-squares maximum likelihood programme to estimate genetic parameters of first lactation 4,209 and 408 records of monthly test day milk yield and peak yield, respectively, of 408 Murrah buffaloes (sired by 62 bulls) calved in between 1993 and 2017 at ICAR-National Dairy Research Institute, Karnal.Result: Heritability of FL305DMY and peak yield was estimated as 0.35±0.17 and 0.33±0.16, respectively. Heritability estimates for mid-lactation monthly test day milk yields were found to be moderate. Genetic correlation of monthly test day milk yields with FL305DMY was positive and highly significant for TD-4 to TD-9 and TD-11. Peak yield showed high genetic and phenotypic association with FL305DMY. High genetic and phenotypic correlation among monthly test day milk yields, peak yield and FL305DMY suggested that TD-4 to TD-9 and TD-11 test day milk yields and peak yield could be used for the selection of elite animals.

Techniques for women empowerment in dairy

Women have great potential to promote agricultural related (secondary agriculture) enterprise. As women play a major role in dairy, they may be motivated for entrepreneurial ventures. Women can be encouraged through local government development organizations for gender sensitization, training, obtaining credit and access to the market. National Dairy Research Institute, Karnal promoted ten women self-help groups in three districts of Haryana under the project of Department of Science and Technology, Ministry of Science and Technology, Government of India. Thus women can become capable of better livelihood through their group activities. The women of the group earn an additional income of between Rs 5000 and Rs 20000 per month.

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

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.

INTERDEPENDENCE AND DISTRIBUTION OF SUBCLINICAL MASTITIS AND INTRA-MAMMARY INFECTION AMONG UDDER QUARTERS IN JERSEY CROSSBRED COWS

The study was aimed to investigate the interdependence and distribution of subclinical mastitis (SCM) and intra-mammary infection (IMI) among udder quarters in Jersey crossbred cows reared in hot-humid environment. Total 366 quarter wise morning milk samples were collected aseptically after performing California mastitis test (CMT) at milking byre itself to evaluate the incidence of infection in experimental cows maintained at cattle yard, ICAR- National Dairy Research Institute, Eastern Regional Station, Kalyani, West Bengal and subjected to microscopic method of somatic cell count to estimate the level of intra-mammary infection. The overall quarter wise incidence rate of IMI and SCM in Jersey crossbred cows was 54.65% and overall arithmetical mean (±SE) of test day SCC (logarithmic) was 5.377 ± 0.039. The percent incidence of SCM in different quarter was 51.14, 59.79, 48.94 and 58.70 in left fore (LF), left hind (LH), right fore (RF) and right hind (RH) quarters respectively. The higher incidence was observed in hind (59.23%) as comparison to fore (50%) quarters while incidence was found to be slightly more distributed in left (55.56%) than right side (53.76%) quarters. Further, the analysis of variance showed that there was no significant effect of quarter on the log 10SCC level. However, the mean Log 10SCC was found higher for hind and right quarters numerically only. The trend of subclinical mastitis incidence obtained in the current study point out that, the rate of incidence of SCM in different quarters was not similar and was higher in hind quarters and therefore, hind and right side quarter required attention during different udder health management programmes.

Optimum age at first semen freezing in relation to fertility of Sahiwal breeding bulls

Early selection of bulls having optimum age at first semen freezing play an important role in improving reproductive performance in a dairy herd. Twenty seven years data (1987-2013) on age at first semen freezing (AAFSF), conception rate based on first A.I. (CRFAI) , overall conception rate (OCR) and birth weight (B.WT) of 41 Sahiwal bulls belonging to 8 sets of Sahiwal improvement programme at ICAR-National Dairy Research Institute, Karnal, Haryana, India; were adjusted against environmental effects and subsequently analysed. Simple and multiple regression models were used for prediction of CRFAI and OCR of Sahiwal bulls. Among the three developed models (I to III), it was observed that Model III having age at first semen freezing and birth weight fulfil the accuracy of model i.e.; having high coefficient of determination (R2) value (CRFAI = 67% and OCR= 69%), low mean error sum of square (MSSe), low conceptual predictive value (CP value) and low Bayesian information criterion (BIC). The results revealed that optimum age at first semen freezing of Sahiwal bulls should be 2.5 - 3.0 years for 3.10% higher conception rate based on first A.I. (48.86%) and 4.39% higher overall conception rate (48.78%) in comparison to Sahiwal bulls with more than 3.5 years of age (CRFAI :- 45.76% and OCR :- 44.39%).

Genetic evaluation of reproductive traits in Jersey crossbred heifersat an organized farm of eastern India

The present study was conducted on data of reproductive traits (viz., age at first service and age at first calving) in Jersey crossbred heifers, maintained at the Eastern Regional Station of ICAR-National Dairy Research Institute, Kalyani, West Bengal over a period of 38 years (1977-2014) to determine the effects of genetic and non-genetic factors. The data were classified according to season of birth, period of birth of animals and distributed in eight genetic groups having different level of Jersey inheritance. The least square mean of age at first service (AFS) and age at first calving (AFC) were 750.61±12.35 and 1089.36±13.99 days respectively. Sire had highly significant (P<0.01) influence on both AFS and AFC in the present study whereas, the genetic group had only significant effect on age at first calving. The half-bred of Jersey and Tharparkar crosses (1/2 Jersey-1/2 Tharparkar) had significantly lower AFC (987.47±43.21 days) than half-bred of Jersey and Red Sindhi and other crosses in this study. Moreover, the animals having less than 50 % and more than 62.5 % Jersey inheritance had highest AFC than other crosses. On the other hand, period of birth had significant effect on both AFS and AFC; however, season of birth only influenced AFC. Heritability estimates of AFS and AFC were observed 0.46±0.19 and 0.30±0.19 respectively. Strong genetic correlation (0.81±0.19) was estimated between these traits. Since, these traits have moderate to high heritability, it indicates faster improvement of these traits through selection.

Evaluation of bull fertility of Sahiwal breeding bulls

In the present investigation, bull fertility of Sahiwal breeding bulls has been studied. The study was conducted on records of 43 Sahiwal bulls maintained under 8 sets of Sahiwal breeding project at ICAR- National Dairy Research Institute, Karnal (India). The data on bull fertility of Sahiwal breeding bulls during 27 years (1987-2013) were analysed. The presented study revealed that the average conception rate based on first AI and overall conception rate of Sahiwal breeding bulls were estimated as 45.95% and 46.38 %. Average sire conception rate of Sahiwal breeding bulls range from – 2% to + 3% and – 2% to + 4 % for conception rate based on first AI and overall conception rate. It has been observed that the average conception rate based on first AI was lower as compare to overall conception rate and higher conception rate of Sahiwal breeding bulls is having higher sire conception rate.

Efficiency of various measures of persistency of milk yield in Sahiwal cattle

The first lactation production records of 351 Sahiwal cows maintained at National Dairy Research Institute, Karnal over a period of 52 years (1961-2012) were used to estimate the persistency measures using different methods viz. Rao and Sundaresan method, 1982 (P₁), P_TOMAX2 (P₂), P_TOMAX3 (P₃), P_SD2 (P₄), P_SD3 (P₅), P_YV (P₆) and Wood's function (P₇). The average persistency of milk yield estimated by above different methods viz. was 194±1.10, 145.10±0.81, 156.71±1.01, 2.29±0.04, 2.20±0.03, 1.00±0.03 and 0.14±0.02, respectively. The T_OMAX2 method was found to be most efficient out of all ratio methods and P_SD3 method was observed to be most efficient amongst variation of yields method. However, mathematical lactation curve model was found to be least efficient as compared to other methods for estimation of persistency.

Effect of non-genetic factors on age at first freezing and age at first use in Murrah bulls

In present investigation, the effect of non-genetic factors on age at first freezing and age at first use in Murrah breeding bulls has been studied. The data on reproduction traits of 57 Murrah bulls under NDRI (National Dairy Research Institute) centre belonging to 14 sets of Network Project on Buffalo Improvement at ICAR-NDRI, Karnal (Haryana), India during 20 years (1993-2013) were analysed using fixed linear model. The data were classified into various sub-classes for season of freezing and use, period of freezing and use, parity, stages of lactation and age groups of buffalo for age at first freezing and age at first use of Murrah breeding bulls. The average age at first freezing and use of Murrah bulls was estimated as 3.46 ± 0.08 years and 4.05 ± 0.13 years with the coefficient of variation of 14.43 % and 12.27%. The overall least-squares means for age at first freezing of Murrah bulls was estimated as 3.38 ± 0.01 years. Period and season of freezing had significant effect (P

Effect of genetic and non-genetic factors on milk yield and milk constituents on Sahiwal cattle

The present study pertained to records on milk production and milk constituents of 259 Sahiwal cattle with 600 lactations spread over a period of 10 years from 2001 to 2010, collected from Dairy Cattle Breeding division of National Dairy Research Institute, Karnal, Haryana. To study the effect of various genetic and non-genetic factors on milk yield and milk constituents traits, mixed model least square analysis was used for analysis of data. Overall least square mean for all lactation traits of total milk yield (TMY), milk yield in 305 days or less (305MY), lactational average fat % (LFA) and lactational average solid not fat % (LSA) were 1880.39 ± 73.82 Kg, 1782.97 ± 68.37 Kg, 4.71 ± 0.01 % and 8.81 ± 0.01 % respectively. Analysis of variance showed that the differences were statistically significant for the effect of sire on TMY and 305MY; period on all the traits except TMY; parity on 305MY. However the effect of season of calving was not found significant on all the traits.