Molecular dissection of a quantitative trait locus: a phenylalanine-to-tyrosine substitution in the transmembrane domain of the bovine growth hormone receptor is associated with a major effect on milk yield and composition.

Amperometric immunosensor for prolactin hormone measurement using antibodies loaded on a nano-Au monolayer modified ionic liquid carbon paste electrode.

Brucellosis is one of the most prevalent bacterial zoonosis of worldwide distribution. The disease is caused by Brucella spp., facultative intracellular pathogens. Brucellosis in animals results in abortion of fetuses, while in humans, it frequently manifests flu-like symptoms and a typical undulant fever, being osteoarthritis a common complication of the chronic infection. The two most common ways to acquire the infection in humans are through the ingestion of contaminated dairy products or by inhalation of contaminated aerosols. Brucella spp. enter the body mainly through the gastrointestinal and respiratory mucosa; however, most studies of immune response to Brucella spp. are performed analyzing models of systemic immunity. It is necessary to better understand the mucosal immune response induced by Brucella infection since this is the main entry site for the bacterium. In this review, some virulence factors and the mechanisms needed for pathogen invasion and persistence are discussed. Furthermore, some aspects of local immune responses induced during Brucella infection will be reviewed. With this knowledge, better vaccines can be designed focused on inducing protective mucosal immune response.

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Immune Response to Mucosal Brucella Infection.

Genetic effects for many dairy traits and for total economic merit are evenly distributed across all chromosomes. A high-density scan using 38,416 single nucleotide polymorphism markers for 5,285 bulls confirmed 2 previously known major genes on Bos taurus autosomes (BTA) 6 and 14 but revealed few other large effects. Markers on BTA18 had the largest effects on calving ease, several conformation traits, longevity, and total merit. Prediction accuracy was highest using a heavy-tailed prior assuming that each marker had an effect on each trait, rather than assuming a normal distribution of effects as in a linear model, or that only some loci have nonzero effects. A prior model combining heavy tails with finite alleles produced results that were intermediate compared with the individual models. Differences between models were small (1 to 2%) for traits with no major genes and larger for heavy tails with traits having known quantitative trait loci (QTL; 6 to 8%). Analysis of bull recessive codes suggested that marker effects from genomic selection may be used to identify regions of chromosomes to search in detail for candidate genes, but individual single nucleotide polymorphisms were not tracking causative mutations with the exception of diacylglycerol O-acyltransferase 1. Additive genetic merits were constructed for each chromosome, and the distribution of BTA14-specific estimated breeding value (EBV) showed that selection primarily for milk yield has not changed the distribution of EBV for fat percentage even in the presence of a known QTL. Such chromosomal EBV also may be useful for identifying complementary mates in breeding programs. The QTL affecting dystocia, conformation, and economic merit on BTA18 appear to be related to calf size or birth weight and may be the result of longer gestation lengths. Results validate quantitative genetic assumptions that most traits are due to the contributions of a large number of genes of small additive effect, rather than support the finite locus model.

Distribution and location of genetic effects for dairy traits.

Bovine brucellosis remains a persistent infection in ruminants in Pakistan. A total of 828 (409 buffaloes and 419 cattle) sera were collected from 11 institutional-owned livestock farms in Punjab, Pakistan. The samples were tested by rose bengal plate agglutination test (RBPT) and indirect enzyme-linked immunosorbent assay (iELISA). The seroprevalence along with 95% confidence interval (CI) was determined. Univariable and multivariable analysis of the epidemiological background data was conducted and odds ratio (OR) was calculated to understand any association between the risk factors and the seroprevalence. An overall seroprevalence of 3.9% (Positive/Tested = 32/828) and 3.3% (27/828) was detected by RBPT and iELISA, respectively. The seroprevalence of 5.6% (CI 3.6–8.3) and 4.7%, (CI 2.8–7.2) and the odds ratio of 2.63 (CI 1.20–5.77) and 2.50 (CI 1.08–5.78) for testing positive by RBPT and iELISA, respectively were significantly higher (p < 0.05) in buffaloes than in cattle. Breed, sex, history of abortion and retention of fetal membranes (RFM) in the animals were not found statistically significantly associated with the infection. RBPT and iELISA based results agreed almost perfect (k = 0.877). In total, Brucella abortus-DNA (9/27) was amplified from seropositive samples by real-time polymerase chain reaction. This study identified for the first time the etiological agents of brucellosis at a molecular level at institutional-owned livestock farms in Pakistan.

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Serological and Molecular Detection of Bovine Brucellosis at Institutional Livestock Farms in Punjab, Pakistan.

The present study was carried out to identify genome-wide genetic markers and variants in candidate genes for production and reproduction traits in Sahiwal cattle using a cost-effective reduced representation sequencing method. A total of 258,231 genome-wide SNPs were identified in Sahiwal cattle with reference to Bos indicus genome, of which 150,231 were novel SNPs. Among the high-confidence SNPs identified, 91.86% and 27.30% were genotyped in 50% and 100% of the samples. Mapping of the identified SNPs revealed 525 SNPs in candidate genes related to production traits while 333 SNPs were mapped to candidate genes related to reproduction traits. The SNPs identified in this study will facilitate further insights on tropical adaptation, domestication history and population structure of indigenous cattle. The variants in candidate genes identified in this study will serve as useful genetic tools, in the quest for phenotype modifying nucleotide change and help in designing appropriate genetic improvement programs.

Genome-wide discovery of SNPs in candidate genes related to production and fertility traits in Sahiwal cattle

Puberty is a period at which sexually organs are functionally developed and animals become able to release the gametes. A cow maturing at early age will also calve at early age and produces more milk in her life time. Delayed sexual maturity has a profound effect on the economics of dairy farm. The objective of this review is to study factors affecting age at puberty. Many factors like species, genetic potentiality or breed, plane of nutrition, growth, body weight, role of different hormones, health and other managemental conditions are responsible for the growth, puberty and sexual maturity in animals. Age at puberty can be improve by different practices but the environment improvement and new nutritional practices are more effective. New modern hormonal technologies, proper management, housing, feeding system of the dairy animals can also reduce the age of puberty and sexual maturity.

Strategies for Attaining Early Puberty in Cattle and Buffalo:A Review

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.

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

Aim: The objective of this study was to investigate the effect of genetic and non-genetic factors and estimate the genetic parameter for gestation length (GL) of Jersey crossbred cattle. Materials and Methods: The data included the 986 parturition records on Jersey crossbred cattle maintained at the Eastern Regional Station of ICAR-National Dairy Research Institute, Kalyani, West Bengal, India during 36 years (1978-2013). The data were analyzed applying mixed model least square technique considering the fixed effects of genetic group, season of calving, period of calving, parity of animal, birth weight, and sex of calf born from animal. The effect of sire was included as a random effect in the model. Results: The genetic group of animal, season of calving, parity of animal, and birth weight of calf born were found to be a significant source of variation in the GL, whereas the period of calving and sex of calf did not affect this trait. Cows with 62.5% Jersey inheritance had the shortest and longest GLs, respectively. Cows calved in summer and rainy season had shorter GL than those calved in the winter season. Older cows in 4 th parity carried calves for longer days than the cows in 1 st parity. The increase in calf birth weight significantly (p<0.01) contributed to a linear increase in GL value in this study. The heritability estimate of GL was 0.24±0.08. Conclusion: It can be concluded that selection for lower GL without distressing future growth of calf can be used to reduce calving difficulty, but a very small standard deviation of GL limits the benefit. Moreover, more accurate prediction of calving date will help in better management and health care of pregnant animals.

http://www.veterinaryworld.org/Vol.9/April-2016/3.pdf

Genetic and environmental causes of variation in gestation length of Jersey crossbred cattle

The aim of sexed semen is to produce a calf of a specific sex. The use of sexed semen increases the rate of genetic gain not only from the daughter-dam path but also through production of superior male from elite cows for future breeding. Gender selection using sexed semen from genetically elite bulls is imperative to meet the projected demand of 191.3 million tones of milk by 2020 in the country. The demand of sex semen in dairy cattle is also increasing in order to dispose the large number of unproductive males, to ensure required number of progenies per bull under progeny testing programme and to reduce the replacement cost on heifers. In India, this technique is gradually been adopted by many states like Punjab, Haryana, West Bengal, Kerala etc. However, high cost and lower fertility limits its wider use across the country. Furthermore, there is need to standardize the lower dosage of spermatozoa, site of deposition for AI with good conception rate in Indian conditions. Optimal use of sexing technology also requires excellent and careful animal management (nutrition, disease control, estrus detection, semen handling, and insemination technique) for obtaining higher efficiency. More research needs to be carried out to make it feasible in order to extend this technique in our country.

Anshuman Kumar

Papers

Genome-wide discovery of SNPs in candidate genes related to production and fertility traits in Sahiwal cattle

Strategies for Attaining Early Puberty in Cattle and Buffalo:A Review

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

Genetic and environmental causes of variation in gestation length of Jersey crossbred cattle

Current Status, Scope and Constraints of Sexed Semen-An Indian Perspective