Present study was carried out with the aim to determine the effect of genetic and non-genetic factors on milk production efficiency traits and their genetic control. Data on milk production efficiency traits i.e. total milk yield per day of lactation length and total milk yield per day of calving interval in Jersey crossbred animals maintained at organized herd of ICARNational Dairy Research Institute, Eastern Regional Station, Kalyani, Nadia, West Bengal spread over 29 years (1986- 2014) were analyzed in the study. The overall least-squares means of total milk yield per day of lactation length and total milk yield per day of calving interval were estimated as 6.97&plusmn;0.21 and 6.02&plusmn;0.23 kg/day, respectively. The data was grouped into different sub-classes of season of calving, period of calving, parity and genetic group of animals. The random effect of sire had shown significant (p&lt;0.01) influence on milk production efficiency traits. Various environment factors significantly affected the milk production efficiency traits indicating the scope of improvement in management of these crossbred animals. The heritability estimates of 0.54 for TMY/LL and 0.63 for TMY/CI were high in magnitude which suggests that fast genetic progress can be made, if these animals are selected based on the milk production efficiency traits.

Genetic analysis of milk production efficiency traits in Jersey crossbred cattle

Background: Herd life is a crucial economic trait, since it affects both total milk yield over a lifetime and the expenses associated with herd replacement. The genetic improvement of longevity traits is frequently challenging due to their typically poor heritability. Consequently, employing indirect selection based on production and reproductive attributes genetically related to longevity may yield a more efficacious breeding strategy. Assessing genetic parameters and interrelations among these traits is crucial for developing effective breeding strategies in jersey crossbred cattle. 
 
Methods: This research examined the performance records of 357 Jersey crossbred cows over a span of 39 years (1980-2018). Genetic parameters were assessed for various longevity-related traits, including herd life (HL), productive herd life (PHL), total milk production (TMP), number of days in lactation (NDL) and number of lactations completed (NLC). Their correlations with production traits, including first lactation 305-day milk yield (FL305MY) and first lactation total milk yield (FLTMY), alongside reproductive traits. [Age at first calving, service period and calving interval] were examined. Heritability estimations were derived via the paternal half-sib approach and a restricted maximum likelihood (REML)-based animal model. Covariance component analysis was employed to determine genetic and phenotypic associations among characteristics. 
 
Result: Estimates of heritability obtained from paternal half-sib analysis were 0.08&plusmn;0.15 for HL, 0.06&plusmn;0.14 for PHL, 0.23&plusmn;0.17 for TMP, 0.26&plusmn;0.17 for NDL and 0.38&plusmn;0.18 for NLC. Estimates derived from the animal model varied between 0.05 and 0.18, signifying a modest to moderate additive genetic impact on longevity traits. The genetic correlations observed among longevity and productivity traits varied from 0.37 to 0.71, indicating positive correlations, although the phenotypic correlations were somewhat less. Most reproductive traits demonstrated low to moderate positive genetic associations with longevity traits, with the exception of the association between NLC and AFC. The identified correlation structure indicates that the selection for increased longevity may concurrently boost milk production without adversely impacting reproductive efficiency. 
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Genetic Analysis of Herd Life Traits and its Relationship with Production and Reproduction Traits in Jersey Crossbred Cattle

Background: A study was carried out to compare, the nutritional composition of manures from indigenous Bargur cattle and Jersy Cattle in the Bargur hills of Anthiyur Taluk in Erode district of Tamil Nadu, India. The moisture content was higher in Jersy cattle at 52% and free-ranging cattle with 37%, but the highest pH values were noticed in dry manure samples of Jersy cattle. Similarly, the highest values of NPK, trace elements and minerals such as Mg, Zn and Fe were also noticed in dry manure samples of Jersy cattle than in indigenous Bargur cattle, but the highest percentage of Cu and organic carbon was observed in the free-ranging Bargur cattle. However, the highest growth rate of Lagenaria siceraria plant was shown in the manure of Bargur cattle. 
 
Methods: Fresh manure samples were collected from Bargur and Jersey cattle, which were sun-dried. The manure samples further analyzed for total nutrients like NPK and Ca, Zn, Cu, Fe and Mn using spectrophotometry and experimental methods. In a pot culture study, Lagenaria siceraria seeds were planted in soil mixed with these manures to compare growth effects and chlorophyll content in the plant leaves was quantified using spectrophotometric analysis. 
 
Result: Fresh dung samples of Indigenous Bargur and Jersey Cattle showed differences in color, moisture and nutrient content; Bargur dung had higher organic carbon and trace elements, while Jersey dung had higher NPK levels. In growth tests, plants in Bargur dung exhibited better growth and chlorophyll content than those in Jersey dung or control soil.

Nutritional Composition from Manure of Bovine Native Bargur Cattle and Jersey Cattle in the Anthiyur Taluk of Erode District, Tamil Nadu, India

The karyological investigation using 16 purebred Sahiwal and 16 Jersey X Sahiwal cattle (8 males and 8 females of each genetic group) revealed the diploid chromosome number to be 60. All the 29 pairs of autosomes were acrocentric, while the X &ndash; chromosome was sub-metacentric in both the genetic groups. Acrocentric Y chromosome of Sahiwal differed from small submetacentric chromosome of Jersey X Sahiwal cattle in its morphology. The relative length of autosomes ranged from 1.74 &plusmn; 0.01 to 5.28 &plusmn; 0.02 in Sahiwal and from 1.72 &plusmn; 0.01 to 5.26 &plusmn; 0.02 in Jersey X Sahiwal crosses. X &ndash; Chromosome was the second largest chromosome in both the genetic groups. The contribution of &nbsp;X and Y chromosomes to the total genome were 5.07 and 1.99 per cent to the total genome in Sahiwal and 5.06 and 2.20 per cent &nbsp;in Jersey X Sahiwal cattle, respectively. The arm ratio, centromeric index and morphological index for the X-chromosome of Sahiwal and Jersey X Sahiwal cattle were 1.89, 0.35, 2.87 and 1.84, 0.36, 2.76, respectively. The arm ratio, centromeric index and morphological index for the Y-chromosome of Jersey X Sahiwal cattle were 1.63, 0.35 and 1.41, respectively.

Comparison of chromosomal architecture of Sahiwal&nbsp;and crossbred Sahiwal cattle

<div>Background: The study was conducted to unravel the consequences of abnormal lactation lengths (Extremely short, short, prolong and extremely prolong lactation length) on production and reproduction traits of crossbred cattle (Red Dane x Sahiwal x Holstein Friesian), which otherwise remains unutilized in routine breeding data analysis owing to normalization and standardization of lactation lengths.&nbsp; 
 
Methods: The performance data of 2541 lactations of 1001 crossbred cattle, sired by 146 bulls over a period of 30 years maintained at the Livestock Farms of Guru Angad Dev Veterinary and Animal Sciences University (GADVASU), Ludhiana were used for this study. The data on production and reproduction traits were analysed using general linear model procedures based on extremely short (&lt;102 days), short (102-179 days), prolong (483 - 560 days) and extremely prolong (&ge; 560 days) lactation lengths on the basis of mean lactation length and its standard deviation.&nbsp; 
 
Result: Result indicated that the alteration of lactation lengths affected all important performance traits of crossbred cattle in contemporary as well as in next lactation. The values of 305 days milk yield, lactation milk yield, average fat (%), 305 days fat yield and lactation fat yield of contemporary lactation cycle were higher (P&le;0.05) for the extremely prolong lactation length and reduced for shorter lactations. Similar trend was seen for next lactation cycle of the animal having abnormal lactation length in previous lactation cycle for all traits except calf birth weight, whereas days to reach peak yield and fat yield traits were not significantly affected by lactation length classes. The preferred lactation length for crossbred cattle for optimum performance was concluded as 180 to 483 days ranging one standard deviation from mean lactation length, covering more than 72% of population; however, it needs further studies to break it into groups in terms of productive life and economical merits. Farmers should avoid breeding of animal having extremely short and short lactation lengths, as their production and reproductive traits are lower in successive production cycle.</div>

<div>Abnormal Lactation Lengths and its Consequences on Performance of Crossbred Cattle</div>

<div>Background: Majority of the people believed that, only the native breeds have A2 milk than exotic or crossbred animals. There is no enough research on milk protein variants have been carried out in Indian zebu cattle. Present study was conducted to screen more number of crossbred cattles and buffaloes in Tamil Nadu to identify the frequency of A1 and A2 alleles in the population. 
 
Methods: The study was conducted on 68 cattle and 172 murrah / graded murrah buffaloes to explore the polymorphic variants of &beta;-casein gene. Genomic DNA was extracted by phenol-chloroform method. Polymerase Chain Reaction (PCR) was performed with allele specific primers to amplify a 244 bp long fragment of beta-casein gene and visualized in 2% agarose gel electrophoresis. The population genetic indices were calculated based on the formulas. 
 
Result: In the present study revealed higher level of A2A2 genotype frequency (1.00) and fixation of A2 allele in kangayam cattle and murrah / graded murrah buffalo. The observed frequency of A1A1, A1A2 and A2A2 genotypes were 0.38,0.62 and 0.00 for jersey crossbred and 0.29, 0.71 and 0.00 for HF crossbred cattle. The range of Expected homozygosity (0.50 to 1.00), polymorphism information content (0.30 to 0.38), effective number of alleles (1.00 to 2.00) and level of possible variability realization value (44.54% to 100%) reflected existence of medium genetic variability in studied population.</div>

<div>A Study on &beta;-Casein Gene Polymorphism in Crossbred Cattle and Murrah / Graded Murrah Buffalo in Tamil Nadu</div>

<div>Background: Visualizing the internal genital organs in cattle using vaginoscope or endoscope is a costly affair and practically it is not possible to use this instrument in diagnosis of anatomical defects causing infertility under field conditions. An attempt was made to replace the costly instruments with low cost and easily available borescope in the diagnosis of persistent hymen in a Jersey crossbred heifer and the procedure has been reported for the benefit of field veterinarians and theriogenologists. 
 
Methods: A Jersey crossbred heifer with normal estrous cycle length and that failed to conceive even after 6 inseminations with fertile semen was presented to the Gynaecological ward. Rectal examination revealed a fluctuating swelling in the vagina. Vaginal examination revealed obstruction in the passage and the vaginal speculum could not be progressed into the vagina. Ultrasonographic examination revealed hypoechoic fluid in the vaginal cavity. A novel approach with borescope revealed a clear view of the membranous obstruction at the level of vagino-vestibular junction. Hence, the case was diagnosed as persistent hymen and hymenotomy was performed.&nbsp; 
 
Result: Upon hymenotomy, about two litres of thick, gummy, tenacious reddish brown colored mucus was evacuated from the vagina. The patency was checked and the animal was treated with antibiotics for three days. The animal was inseminated at the subsequent estrus on the 22nd day and pregnancy was confirmed on 45th day. The animal calved normally and delivered a live male calf. Thus, the borescope could be effectively used in the field of animal reproduction as an alternative tool for the diagnosis of developmental defects in the vagina.</div>

<div>Persistent Hymen in a Jersey Crossbred Heifer-A Novel Approach with Borescope</div>

The present study was carried out to evaluate the genetic and non-genetic factors affecting fertility traits viz., number of service per conception (NSPC), service period (SP) and calving interval (CI) and genetic and phenotypic parameters of these traits in Jersey crossbred cattle, maintained at Eastern Regional Station of ICAR-National Dairy Research Institute, Kalyani, West Bengal over a period of 39 years (1976-2014). The least squares means for the NSPC, SP and CI were 1.73&plusmn;0.08 inseminations, 156.37&plusmn;7.47 days and 458.32&plusmn;9.56 days respectively. The study revealed that all the traits were decreasing significantly with parity number. Season was important in determining service period, whereas period of calving influenced calving interval in this study. NSPC, SP and CI did not differ significantly among different genetic groups; but, half-breds of Jersey and Tharparkar (&frac12; Jersey-&frac12; Tharparkar) showed comparatively lower NSPC, SP and CI than half-breds of Jersey and Red Sindhi and other crosses in this study. The random effect of sire was highly significant on all the fertility traits considered in this study. Heritability estimates for NSPC, SP and CI were 0.08&plusmn;0.06, 0.18&plusmn;0.08 and 0.16&plusmn;0.08 respectively. All the three analyzed traits had close genetic relationships. Low to moderate heritability of reproductive traits indicates slow genetic progress through selection and further improvement in reproductive performance can be made either by better management practices or including large number of polymorphic markers associated with fertility in the population to assist animal selection

Genetic analysis of fertility traits in Jersey crossbred cows

<div>Background: Milking behaviour of dairy cows has remarkable influences on their production efficacy. A number of genetic and environmental features controls and affects lactating behaviour of dairy cow. The aim of present study was to investigate the influence of seasons on milking behaviour and milk production of Jersey crossbred cows in tropical climate. 
 
Methods: The experiment was conducted on 94 Jersey crossbred cows maintained at organized dairy farm at ICAR-National Dairy Research Institute, Eastern Regional Station, Kalyani, West Bengal, India and there lactating behavioural features were studied during milking time inside the milking parlour under different seasons. The study period was divided into 3 season&rsquo;s viz. rainy (September-October), winter (November-February) and summer (March-May). 
 
Result: Seasons showed influence upon milking behaviour and milk yield of cows. Temperament of cows were least (1.91&plusmn;0.03) during winter seasons as compare to rainy and summer (2.15&plusmn;0.03; 2.09&plusmn;0.03) respectively and it differed significantly (P&lt;0.01), simultaneously daily milk yield were also more (9.36&plusmn;0.11) kgs during winter seasons as compare to rainy and summer (6.63&plusmn;0.13; 8.58&plusmn;0.13) respectively and it differed significantly (P&lt;0.01). It can be concluded from the study that seasons showed significant influence on the milking behavioural features and milk yield in Jersey crossbred cows in tropical climate, which suggests that if dairy animals get favourable micro-climatic environment and reduced level of environmental stress they will behave more favourably and simultaneously their production efficacy also inclines.</div>

Effect of Seasons on Expressions of Milking Parlour Behaviours and Milk Yield of Crossbred Jersey Cows in Tropical Climate

<div>Background: Lactation curve patterns are currently integrated in dairy cow&rsquo;s management software. Lactation curve modeling is useful for monitoring individual yields for diet planning, determining optimum strategies for insemination and genetic evaluation. It also helps for predicting expected missing values on field records and gives concise summary of biological efficiency and persistency of dairy cows. 
 
Methods: The study was aimed to characterize the lactation curve pattern for crossbred dairy cattle using different non-linear models. During the period 1991 to 2018, daily milk yield (DMY) consisted of 281698 records of 750 crossbred dairy cows maintained at Livestock Farms. GADVASU, Ludhiana, were collected for the study. Different non-linear models viz. exponential decline function (EDF), parabolic exponential model (PEM), inverse polynomial model (IPM), gamma-type function (GTF), mixed log function (MLF) and Ali and Schaeffer model (ASF) were used for the analysis. The model(s) that best fit and describe the curve characteristics was selected on the basis of coefficient of determination (R2), coefficient of variation (CV), Akaike information criterion (AIC)&nbsp;and mean square error (MSE). 
 
Result: The study clearly revealed that the PRM gave highest fit to DMY data with R2, MSE, AIC and CV values of 98.10%, 0.087, -743.31 and 2.37%, respectively. The IPM had also best fitted the observed DMY data with highest R2 (98.05%), lower MSE (0.089), low AIC (-735.8972) and lower CV (2.40%) values. The fitting of observed DMY data with predicted DMY were also found to be higher in the MLF (R2= 96.46%, MSE= 0.159, AIC= -558.16 and CV= 3.21%) and GTF (R2= 95.85%, MSE= 0.190, AIC= -505.24 and CV= 3.50%), whilst the EDF and PEM Models depicted relatively low fit to the DMY data when compared with the other non-linear models. However, IPM and GTF models can be used for accurate prediction of daily milk yield in the crossbred cattle population because they were typical standard lactation curves.</div>

Genetic analysis of milk production efficiency traits in Jersey crossbred cattle

Genetic Analysis of Herd Life Traits and its Relationship with Production and Reproduction Traits in Jersey Crossbred Cattle

Nutritional Composition from Manure of Bovine Native Bargur Cattle and Jersey Cattle in the Anthiyur Taluk of Erode District, Tamil Nadu, India

Comparison of chromosomal architecture of Sahiwal and crossbred Sahiwal cattle

Abnormal Lactation Lengths and its Consequences on Performance of Crossbred Cattle

A Study on β-Casein Gene Polymorphism in Crossbred Cattle and Murrah / Graded Murrah Buffalo in Tamil Nadu

Persistent Hymen in a Jersey Crossbred Heifer-A Novel Approach with Borescope

Genetic analysis of fertility traits in Jersey crossbred cows

Effect of Seasons on Expressions of Milking Parlour Behaviours and Milk Yield of Crossbred Jersey Cows in Tropical Climate

Characterization of Lactation Curve Patterns using Non-linear Models in Crossbred Dairy Cattle