<div><strong>Background: </strong>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;<br />
<br />
<strong>Methods: </strong>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;<br />
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<strong>Result: </strong>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><strong>Background: </strong>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.<br />
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<strong>Methods:</strong> 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 <em>viz</em>. 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 (R<sup>2</sup>), coefficient of variation (CV), Akaike information criterion (AIC)&nbsp;and mean square error (MSE).<br />
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<strong>Result: </strong>The study clearly revealed that the PRM gave highest fit to DMY data with R<sup>2</sup>, 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 R<sup>2 </sup>(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>


<div>Characterization of Lactation Curve Patterns using Non-linear Models in Crossbred Dairy Cattle</div>


<p style="text-align: justify;">The paternally inherited Y chromosome markers have been used widely in population genetic studies to trace paternal lineages, to understand differences in migration pattern and populations admixture in animals. In the absence of crossing over, Y-chromosomal markers in the non-recombining male-specific region (MSY) are mostly transmitted as a haplotype. Recent studies of five polymorphic sites on DDX3Y, UTY and ZFY genes of bull MSY assisted in the identification of three haplotypes (Y1, Y2 and Y3) in contemporary cattle. Here we report the screening of five SNPs (ZFY9- 120&gt; C/T; ZFY10- 655&gt; C/T; DDX3Y1- 425&gt;C/T; DDX3Y7 -123&gt;C/T and UTY19-423&gt;C/A) of bull MSY employing optimized and validated allele-specific PCR (AS-PCR) protocols that are useful in effective differentiation of &nbsp;bull/semen samples of Bos indicus and Bos taurus origin. &nbsp; Three haplotypes (Y1, Y2 and Y3) were identified in the present study by the screening of 181 bulls from 10 native cattle breeds and 50 HF crossbred. Y1 and Y2 haplotypes were restricted to HF crossbred with a frequency of 0.98 and 0.02, respectively. The high frequency of Y1 haplotype is possibly due to the occurrence of Y1 lineage predominantly in HF bulls. All the native cattle breeds were observed to have pure indicine haplotype (Y3). These cost effective AS-PCR protocols may be useful for reliable and accurate genotyping of Y-SNPs in diverse native cattle breeds, exotic and crossbred cattle populations.&nbsp;</p>


<p>Y-chromosome variation in Indian native cattle breeds and crossbred population<br />
&nbsp;</p>


<div><strong>Background:</strong> 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.<br />
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<strong>Methods: </strong>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.<br />
<br />
<strong>Result:</strong> In the present study revealed higher level of A2A2 genotype frequency (1.00) and fixation of A<sub>2</sub> 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><strong>Background:</strong> The information about milk quality of different breeds of cattle and buffalo is still scanty. The objective of the study was to the compare milk fatty acid composition and mineral concentration in the crossbred cattle and indigenous cattle and buffalo reared on same farm.&nbsp;<br />
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<strong>Methods:</strong> This study was conducted on 187 individual milk samples, which includes 124 crossbred <em>Vrindavani</em> cattle, 19 indigenous cattle and 44 Murrah buffaloes.&nbsp; &nbsp;<br />
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<strong>Result:</strong> The Murrah buffalo milk had significantly (P&le;0.05) higher concentration of fat and saturated fatty acids than indigenous or crossbred cow&rsquo;s milk. The mono unsaturated fatty acid (MUFA) and poly unsaturated fatty acid (PUFA) contents (C16:1, C20:2, C20:4n6 and C22:6N3) were significantly higher in indigenous cows compared to crossbreds and Murrah buffalo. The concentration of iron and zinc were significantly (P&le;0.05) higher in indigenous cattle, whereas, the contents of Cu and Mn were higher in Murrah buffalo.</div>


<p>Comparative Analysis of Milk Fatty Acids and Minerals of Indigenous <em>vis-&agrave;-vis</em> Crossbred Cattle and Buffaloes</p>


<div><strong>Background:</strong> Mastitis is the most common and economically important disease of dairy cattle. Subclinical mastitis is a more important form in India than clinical mastitis. Subclinical mastitis (SCM) detection done by periodic examination of the udder health by evaluation of milk at the herd level or the individual cow level by milk somatic cell count (SCC), followed by culture of random milk samples. The presented study was undertaken by survey and sampling of milk from lactating crossbred cattle of unorganized dairy farms and farmer&rsquo;s dairy of the peri-urban region of middle Indo-Gangetic Plains. The objective of the study was to monitor the status of SCM in crossbred cattle and associated changes in milk constitutes and oxidative stress in milk.&nbsp;<br />
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<strong>Methods:</strong> A total of 147 lactating crossbred cattle were screened for SCM using the modified California Mastitis Test (CMT) using detergent based CMT reagent and compared with conventional CMT reagent, followed by SCC, milk constituents, bacterial isolation and antibiotic sensitivity testing (ABST). General information was collected in pre-tested questionnaire. The data obtained were statistically treated to evaluate significance of the study.<br />
<br />
<strong>Conclusion: </strong>The overall prevalence of subclinical mastitis in peri-urban cross-bred cattle was 36.74% which varied with parity and stage of milking. Prevalence of subclinical mastitis was highest (55.77%) in cross-bred cattle in mid-lactation and Parity 3-5. The mean SCC was significantly higher (7.21&plusmn;0.27) in subclinical mastitis compared to CMT negative (3.66&plusmn;0.06) milk sample. Somatic cell count was positively and significantly correlated with CMT reactions using conventional CMT reagent (rs= 0.86) as well as modified CMT reagent (rs=0.815) attempted using Spearman rank-order correlation coefficient. The mean values of milk pH, fat and lactic acid acidity increased significantly (P&le;0.01) in SCM compared to the milk of healthy cattle, except lactose which decreased significantly in SCM milk. The common contagious bacteria responsible for SCM isolate were coagulase-positive Staphylococcus spp. (64.82%) isolates from these SCM milk followed by Streptococcus spp. ABST test conducted on random CMT positive milk sample indicated that gentamicin as most sensitive, followed by enrofloxacin. The present finding indicates the suitability of enrofloxacin as the most useful antibiotic for the treatment of subclinical mastitis in cross-bred cattle of the peri-urban area of middle Indo-Gangetic plains.</div>


<p>Status of Subclinical Mastitis in Crossbred Cattle of Peri-urban Unorganized Herd of Middle Indo-gangetic Plains</p>


<div style="text-align: justify;">Present research work was carried out on 50 Sahiwal and 50 HF Crossbred cattle in the Department of Animal Genetics and Breeding of College of Veterinary Science and A H Jabalpur. During the research work the PCR amplified products of 121bp was digested by restriction endonuclease enzyme DdeI, which recognizes G^AATTC sites. The patterns evolved in the present study showed that the presence of one restriction site on one alleles and absence of restriction site on other alleles resulted in the appearance of three bands of 121, 86 and 35bp.This genotype was referred to as A1A2. When both strand had no restriction sites for the enzyme, only one band of 121bp was observed on the gel such genotype was designated as A2A2 type. The &acirc;- casein gene showed A2A2 and A1A2 genotypes were observed in Sahiwal and HF crossbred cattle. The genotypic frequencies of &acirc;-casein (CSN2)/ DdeI gene for A1A1, A1A2 and A2A2 are 0.00, 0.30, and 0.70 in Sahiwal and 0.00, 0.64 and 0.36 in HF crossbred cattle, respectively and the gene frequency A1 and A2 is 0.15 and 0.85 in Sahiwal and 0.32 and 0.68 in HF crossbred cattle. High frequency of A2 allele was observed in both the breeds of cattle under the study.</div>

<div style="text-align: justify;">Polymorphism of beta (b) casein gene and their association with milk production traits in Sahiwal and HF crossbred cattle</div>

<p style="text-align: justify;">The study was undertaken to evaluate the effect of different macro climatic variables on lactation milk yield and lactation length of Holdeo (Holstein Friesian x Deoni) crossbred cattle. Milk data of 145 Holdeo crossbred cows with 619 lactation records and the meteorological data over a period of 15 years (1995-2009) were obtained from Cattle Cross Breeding Project, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani and University Meteorological Observatory, respectively. It was observed that maximum temperature has significant correlation with lactation milk yield; whereas maximum temperature, minimum temperature, sunshine hours and wind speed have significant correlation with lactation length. Regression analysis indicated that all the climatic variables except minimum temperature exhibited significant regression results with lactation milk yield, and maximum temperature, minimum temperature and maximum humidity have significant regression results with lactation length. All the climatic variables considered in the study accounted for 75 % and 65 % direct variation on lactation milk yield and lactation length, respectively, as verified by the value of coefficient of determination (R2). It was observed that lactation milk yield (1136.56 + 21.04 kg.) and lactation length (295.29 + 5.51 days) were highest among the cows calved during winter season as compared to rainy and summer season. &nbsp;All the climatic variables considered in the study accounted for 57% , 56 % &nbsp;and 48 % &nbsp;direct variation on milk yield and 68% , 53 % &nbsp;and 46 % &nbsp;direct variation on lactation length in rainy, winter and summer season, respectively, as verified by the value of coefficient of determination (R2). This research indicated that crossbred cows were sensitive to seasonal changes on their lactation performance. The optimum ranges of temperature; humidity and THI for better performance of crossbred in subtropical region of India were found to be 19-26 oC, 52-66 % and 65-68 %, respectively.&nbsp;</p>


<p>Effect of environment factors on milk production and lactation length under different seasons in crossbred cattle</p>

<p><strong>Background:</strong> This study aimed to investigate the persistence of Foot-and-Mouth Disease Virus (FMDV) in clinically recovered cattle following an outbreak, focusing on both local indigenous breeds (Lakhimi) and crossbred cattle (Holstein Friesian-cross) in Assam.<br />
<strong>Methods: </strong>A total of 129 cattle (36 local and 93 crossbred), clinically recovered from FMD, were included in the study. Oropharyngeal fluid (OPF) samples (n=178) were collected at various intervals post-recovery. FMDV detection was carried out using three molecular diagnostic techniques: Multiplex PCR, reverse transcription loop-mediated isothermal amplification (RT-LAMP) and SYBR Green real-time PCR, all targeting the FMDV 3D gene.<br />
<strong>Result: </strong>FMDV was detected in 38 samples (21.35%) by multiplex PCR, 47 samples (26.40%) by RT-LAMP and 49 samples (27.53%) by SYBR Green real-time PCR. While all three methods showed comparable diagnostic accuracy, real-time PCR proved to be the most sensitive, rapid, reliable and cost-effective technique. FMDV persistence was observed in 24.81% (32/129) of cattle up to the 1st&nbsp;month post-recovery, 11.63% (15/129) up to the 3rd month and 1.55% (2/129) up to the 6th&nbsp;month. Local non-vaccinated Lakhimi cattle exhibited higher rates of viral persistence for serotype O, with 33.33% (12/36), 22.22% (8/36) and 5.55% (2/36) showing persistence at the 1st, 3rd&nbsp;and 6th&nbsp;months post-recovery, respectively. In contrast, vaccinated Holstein Friesian-cross cattle, demonstrated lower persistence rates, with 19.23%&nbsp; for Serotype A and 22.39% for Serotype O at the 1st month and 10.45% for Serotype O at the 3rd&nbsp;month post-recovery. Importantly, no transmission of the virus to healthy in-contact animals was detected during the study period.<br />
Statistical analysis (P=0.23, Chi-square=5.57) revealed no significant difference in viral persistence between local and crossbred cattle, suggesting that factors beyond vaccination status might influence FMDV persistence. However, the findings underscore the critical role of vaccination in reducing viral persistence in recovered cattle.<br />
&nbsp;</p>


<p>Detection of Persistence of Foot and Mouth Disease Virus in Local and Crossbred Cattle of Assam</p>


<p>A total of 1474 and 1935 production and reproduction records of crossbred cattle and Murrah buffaloes from the year 1992 to 2012 were utilized in the present study to investigate breeding efficiency (BE) and various performance traits. Breeding efficiency was calculated using Wilcox and Tomar methods and &nbsp;Least &ndash;squares of Harvey model was used to study the effects of various non-genetic factors (period, season) on breeding efficiency. &nbsp;Average breeding efficiency of Crossbred cattle &nbsp;was 82.31 &plusmn; 0.97% &nbsp;ranging from 75% to 85% by Wilcox method and 98.14 &plusmn; 1.09% ranging from 95% to 99% by Tomar method. Average breeding efficiency of &nbsp;buffaloes was 78.03 &plusmn; 1.01% ranging from 69% to 84% by Wilcox method and 78.39 &nbsp;&plusmn; 0.39% ranging from 74% to 80% by Tomar method &nbsp;under the management conditions. Breeding efficiency correlated positively with weight at calving, milk yield 305 days and milk yield complete in Crossbred cattle and Murrah buffaloes by both methods. The effect of period was significant(&lt;0.01) on the breeding efficiency by Wilcox method and non-significant by Tomar method in Crossbred cattle. The effect of season was non-significant on breeding efficiency by both methods in crossbred cattle. In Murrah buffaloes the effect of period was significant(&lt;0.01) on the breeding efficiency by both methods &nbsp;while the effect &nbsp;season was significant(&lt;0.05) on breeding efficiency by Tomar method and non significant by Wilcox method. Therefore it is imperative to emphasis improvement in the husbandry practices and the introduction of genetic evaluation programmes at the same time.<br />
&nbsp;</p>


Abnormal Lactation Lengths and its Consequences on Performance of Crossbred Cattle

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

Y-chromosome variation in Indian native cattle breeds and crossbred population

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

Comparative Analysis of Milk Fatty Acids and Minerals of Indigenous vis-à-vis Crossbred Cattle and Buffaloes

Status of Subclinical Mastitis in Crossbred Cattle of Peri-urban Unorganized Herd of Middle Indo-gangetic Plains

Polymorphism of beta (b) casein gene and their association with milk production traits in Sahiwal and HF crossbred cattle

Effect of environment factors on milk production and lactation length under different seasons in crossbred cattle

Detection of Persistence of Foot and Mouth Disease Virus in Local and Crossbred Cattle of Assam

Breeding efficiency of Crossbred cattle and Murrah buffaloes at organized dairy farm