<div>Background: Growing demand for improving milk production and rising temperatures due to global warming has increased the thermal load on dairy animals. Physiological parameters such as respiration rate and body temperature mainly determine the adaptability of animals to climate stress. During genetic adaptation, Bos indicus cattle have acquired thermo tolerant genes and when exposed to heat stress conditions, the Bos indicus cattle have lower respiration rates and rectal temperatures than Bos taurus animals. The present study was aimed to study the effect of seasons on the physiological responses in Sahiwal and crossbred cows. 
 
Methods: A total of 50 crossbred cows maintained at Military dairy Farm, Secunderabad and 50 Sahiwal cows maintained at Livestock Farm Complex, College of Veterinary Science, Rajendranagar, PVNRTVU were utilized for the present investigation. The study was conducted during summer (THI = 83.71&plusmn;0.01), rainy (THI = 71.37&plusmn;0.01) and winter (THI = 66.69&plusmn;0.01) seasons. Changes in respiration rate (RR), rectal temperature (RT) and heat tolerance coefficient (HTC) were observed in different seasons in Sahiwal and crossbred cows. 
 
Result: RR (breaths/ min) in Sahiwal cows during summer, rainy and winter were 28.56&plusmn;0.38, 23.38&plusmn;0.38 and 20.54&plusmn;0.38 respectively whereas RR (breaths/ min) in crossbred cows were 44.58&plusmn;0.38, 25.94&plusmn;0.38 and 21.90&plusmn;0.38 respectively. In Sahiwal cows RT (&deg;C) during summer, rainy and winter were 38.52&plusmn;0.03, 38.23&plusmn;0.03 and 38.13&plusmn;0.03 respectively whereas RT (&deg;C) in crossbred cows were 39.22&plusmn;0.02, 38.72&plusmn;0.03 and 37.80&plusmn;0.03 respectively. The magnitude of increase in RR, RT and HTC were found to be higher during summer compared to other seasons in both Sahiwal and crossbred cows. It was observed that Sahiwal cows are less sensitive to heat stress and are better able to regulate their body temperature than crossbred cows when environmental temperature increases during summer. The HTC values were lower in Sahiwal cows in all the seasons studied indicating better thermo tolerance when compared to the crossbred cows.</div>

Effect of Seasons on Physiological Responses in Sahiwal and Crossbred Cows

<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 style="text-align: justify;">Present study was aimed to improve poor quality crossbred bulls semen, as occurrence of poor quality ejaculates are one of the major problems in crossbred bulls. Antioxidants and its combination was tried to overcome such problems. Vitamin E, Vitamin C and Vitamin E+C were supplemented at dose rate of 1mg, 5 mM and 1mg + 5mM per ml respectively in split ejaculates to evaluate semen quality during preservation at refrigerated temperature and cryopreservation. The results showed that semen characteristics were better in antioxidant supplemented ejaculates. Total sperm abnormality were significantly lower (p&lt;0.05) in antioxidant supplemented group. &nbsp;The seminal characteristics of crossbred bull semen showed significantly better (p&lt;0.05) performance on preservation, when fortified with Vitamin E as compared to Vitamin C alone as well as Vitamin E and C in combination. The performance of semen additives, were supportive to semen characteristics especially for Vitamin E, moreover fortification with Vitamin E+C was slightly superior to Vitamin C. It can be concluded that fortification of Vitamin E has beneficial role in semen quality improvement followed by Vitamin E+C and Vitamin C.&nbsp;</div>

Assessment of antioxidants for preservation of crossbred bull semen in Tris based extender

<div>Background: Kashmir Valley, one of the temperate regions of India, has experienced an exponential increase in the milk-production over the last decades. This may be mainly attributed to massive cross-breeding of &lsquo;Local Cattle of Kashmir Valley&rsquo; with the world-class dairy breeds like Jersey and Holstein-Friesian (HF), popularly known as Jersey-Crossbreds (JCB) and Holstein-Friesian Crossbreds (HFCB), respectively. However, no specific guidelines on their breed characteristics is available, which is crucial for their establishment, recognition and management. Precise and standardized morphological details are a primary requisite for application of advanced technologies like automation, Internet of Things (IoT) and robotics. Therefore, the present study aimed to characterize the HFCB and JCB cows. 
 
Methods: Morphologic and morphometric traits of 600 and 447 cows respectively, reared in the Srinagar district of Kashmir, were studied in detatil as per the standard methods. The null-hypothesis set was that the two crossbreds do not differ from each other. 
 
Result: It was observed that two crossbreds differed significantly (p&lt;0.05) with each other in respect of the morphological and morphometrical traits like body size and weight. The study generated a baseline data on these two crossbreds, which is critical not only for their recognition, welfare and scientific management, but shall also act as a reference for global researchers to assess the results of crossbreeding superior dairy breeds in improving the genetic-merit of other breeds worldwide.</div>

Morphological and Morphometrical Studies on the Crossbred Cows under Temperate Climatic Condition of Kashmir Valley

<div>Background: The objective of this study was to find out the association of lactation numbers of crossbred cow with their serum antisperm antibody titre, if any.&nbsp; 
 
Methods: Total 163 numbers of normal breeding crossbred jersey crossbred cows belong to various lactational groups maintained in the Instructional Livestock Farm, College of Veterinary Science, Assam Agricultural University, Khanapara and various private cattle farms in Kamrup district of Assam, India were selected for the work. ELISA was carried out for detection of antisperm antibody (asp-abs) in the test sera. Data were analysed using Chi-square test. 
 
Result: In the present study, out of 163 females 94 (57.67%) animal were found to be positive reactors. The percentage of positive reactors could be detected in 1st, 2nd, 3rd, 4th, 5th and above (5th, 6th, 7th and 9th) lactational group of cows were 16 (72.73%),15 (50.00%), 23 (63.89%), 14 (43.75%), 26 (60.47%) respectively. The highest titre up to the extent of 1:320 was recorded in the sera of cows with 1st, 3rd and 4th lactations. A negative correlation (r = -0.42NS) between the numbers of lactation and 
positive reactors for antisperm antibody (asp-abs) is found in crossbred cows.</div>

Association of Lactation Numbers of Crossbred Cows with Their Serum Antisperm Antibody Titre

<div>Background: Large variation for body size and weight exist among indigenous goat breeds. Many livestock development agencies recommending crossbreeding of large size goats with small and medium sizes to increase the body size, growth rate, dressing weight and dressing percentage of progeny without being systemic data and combining ability among breeds used. In view of above crossbreeding experiment was conducted by crossing Jamunapari male with Barbari female.&nbsp; 
 
Methods: Ten Barbari females were crossed with medium size two Jamunapari male. The crossbred males (07) were kept under stall feeding on high input diet along with Barbari and Jamunapari pure-bred males at weaning. The growth (body weight and average daily weight gains) were studied up to 9 months of age. The animals were slaughtered at 9 months and carcass traits (dressing weight and percentage) were studied. 
 
Result: Pre-weaning growth (0-3m) was statistically similar (P&gt;0.05) in all the group of goats. However different trend was obtained in post weaning growth stage, ADG being significantly (P&lt;0.05) more in Jamunapari breed (94.10g) as compared to Barbari (73.43g) and crossbred goats (74.24g). The dressing (%) was significantly (P&lt;0.05) higher in Jamunapari goats (47.28) as compared to Barbari (40.47) and crossbred (40.44). The carcass results revealed that growth and carcass performance was highest in Jamunapari kids and significantly different from pure bred Barbari and crossbred kids. However, Carcass traits (Carcass weight and Dressing percent) performances were not significantly different in between Barbari and Jamunapari x Barbari crossbred kids. Thus, crossing of Jamunapari with Barbari breed is not being suggested to increase body weight and carcass attributes of crossbreed progeny.</div>

​Comparative Growth Performance and Carcass Characteristics of Jamunapari, Barbari and their Crossbred under Stall Fed Condition

<div>Background: Genotype environment interaction plays vital role in animal productivity. Heat stress is one of the major environmental stressor affecting milk production and measured in terms of temperature humidity index (THI). Indian milk industry largely depends on crossbred cows bearing different degree of exotic inheritance. Thus, the role of genotype (genetic group) of the crossbred cows and environment (THI) interaction plays vital role in Indian climate which is mostly tropical in nature. Therefore, study was undertaken to examine the existence of genetic group &times; THI in crossbred dairy cows reared at institute herd of ICAR-National Dairy Research Institute, Eastern Regional Station, Kalyani, West Bengal.&nbsp; 
 
Methods: A total of 12364 records each of monthly milk yield (MMY) and average daily milk yield in a month (AMY) of crossbred cows spanned over twenty two years (1994-2015) and weather parameters(temperature and relative humidity) for the corresponding years were collected from institute records. The data were classified into 8 genetic groups according to the genetic composition and 3 THI groups (THI &lt;72, THI 72-78 and THI above 78). The interaction model was used to study the G&times;E interaction study using least squares analysis.&nbsp; 
 
Result: Effect of non-genetic factors (parity, period of calving and stage of lactation) was found to be highly significant (P&lt;0.01) and genetic group &times; THI was significant (P&lt;0.05) of on both MMY and AMY. Genetic group bearing 50% Jersey and 50% Red Sindhi or Tharparkar were the most heat tolerant breeds. Jersey crossbred cows were more heat tolerant than Holstein crossbred cows. Crossbred cows with 50% Jersey inheritance performed better than higher Jersey inheritance during periods of THI above 72.</div>

Genotype Environment Interaction on Milk Production Traits of Crossbred Dairy Cows under Tropical Climatic Condition of India

<div>Background: Various mathematical models have been tried by different researchers to fit the lactation curves in indigenous, exotic and crossbred cows maintained in organised farms only. Hence, this study was aimed to fit various lactation models and to identify the best fit model (s) for prediction of milk production in crossbred dairy cows in field conditions. 
 
Methods: Multistage random sampling procedure was used for selection of 100 dairy cows for the purpose of data collection. The monthly milk yield data (up to 10 months of lactation) of the selected crossbred cows reared in field conditions of Tamil Nadu State, relating to the period from 2017-20, were collected for lactation curve modelling. The milk data so collected were used to fit 14 lactation curve models in the study. The highest Coefficient of Determination (R&sup2;) value and the least Root Mean Square Error (RMSE) value were used as the criteria to select the best fit model(s). 
 
Result: The overall average total milk production was estimated to be 2223.19 kg per lactation in 10 months of lactation in the selected crossbred cows. Average daily milk yield at the first month of lactation was 9.16 kg and the highest daily milk yield of 9.56 kg was observed at the second month of lactation. At the end of the lactation, the lowest yield was 5.01 kg per day and hence the overall average daily milk yield was found to be 7.41 kg. Based on the selection criteria, the Mitscherlich X Exponential model was identified as the best fit model, followed by Ali and Schaeffer and Morant and Gnanasakthy model for prediction of milk production in crossbred dairy cows reared in field conditions and the estimated lactation curve model parameters a, b, c and d values for the best fit model were 331.71, 1519.82, 9.56 and 0.07 kg, respectively.&nbsp;</div>

<div>Comparative Evaluation of Lactation Curves of Crossbred Dairy Cows in Field Conditions in Tamil Nadu, India&nbsp;</div>

<div style="text-align:justify">Background:&nbsp;The objectives of this study were to estimate the effects of direct additive and dominance on litter traits and to predict the reproduction of un-tested crossbred sows between Danish Yorkshire (Y) and Danish Landrace (L) pigs in Vietnam.&nbsp; 
 
Methods:&nbsp;Litter traits data were obtained between 2014 and 2017 in Binh Thang and Khang Minh An breeding farms, with 671 litters of crossbred sows crossed from 1,308 litters of purebred Yorkshire and Landrace sows.&nbsp; 
 
Result:&nbsp;In F1 sows, heterosis was manifested in all traits with 6.7-6.4% for TNB; 5.4-6.2% for NBA; 4.4-4.8% for NW and 5.7-6.0% for AWW traits. Additionally, direct dominance was the most positive effect on litter traits in crossbred sows. In rotational crossbred sows of L (YL) and L (LY), while the value of litter traits remarkably decreased in comparison with F1 groups, it was a noticeably higher than that of the purebred sows by 1.4-3.0%. In un-tested crossbred groups of Y (YL) and Y (LY), predicted values for litter traits were equal in tested crossbred groups of L (YL) and L (LY) and lower than F1 crossbred sows.</div>

Effects of Direct Additive and Direct Dominance on Litter Traits in Crossbred Sows between Danish Yorkshire and Danish Landrace Pigs in Vietnam

Background: Cellular tolerance to heat stress is mediated by heat shock proteins (HSPs). The HSPs act as molecular chaperones and are transcribed in response to stress. Among different families of these proteins, HSP70 is considered to be related to the development of temperature tolerance. Unraveling polymorphism in heat shock protein genes could be a step towards the identification of genetic markers for selecting heat-tolerant cattle.&nbsp; 
 
Methods: The present study was carried out in Sahiwal (n=50) and Crossbred cows (n=50) with the objective to identify polymorphisms in HSP70 gene. Two fragments (295 and 220 bp) of HSP70 gene were subjected to Polymerase Chain Reaction-Single-Strand Conformation Polymorphism (PCR-SSCP) technique. Statistical analysis was performed to study the association of each SSCP genotype on physiological, production and reproduction traits in Sahiwal and crossbred cows using the univariate GLM model of SPSS 25. 
 
Result: The PCR-SSCP of 295 bp fragment of HSP70 gene revealed two genotypes AA and AB in Sahiwal cows and two genotypes AA and AC in crossbred cows. The association analysis revealed that genotype AA had higher peak milk yield in Sahiwal cows while the same genotype had higher total lactation milk yield, lower service period and calving interval in crossbred cows. The 220 bp fragment was found to be monomorphic in both Sahiwal and crossbred cows.&nbsp;

Association of SSCP Polymorphisms of HSP70 Gene with Physiological, Production and Reproduction Performance in Sahiwal and Crossbred Cows