Effect of Linear Type Traits Influences on Survivability and Longevity of Sahiwal Cattle

Background: The linear type traits are the one of important tools for selection of milch cattle. The lifespan of cattle mostly depends on these linear type traits particularly feet and udder related traits. So it is necessary to measure the linear type traits and effect on longevity of Sahiwal cattle. Methods: The experiment was conducted on 86 Sahiwal cattle maintained in Bull mother experimental farm and government cattle breeding farm, Anjora, Durg (C.G.). The linear type traits in Sahiwal cattle were measured as per the recommendation of International committee for animal recording (ICAR). Result: The different linear type traits were studied the average value of stature 125.39±0.534, Chest width 27±0.49, rump angle 12.75±0.97, rump width 17.32±0.29, rear leg set (side view) 146.03°±0.91, rear leg set (rear view) -3.74±0.15, udder depth 18.97±0.43, udder cleft 2.77±0.95, rear udder height 24.06±0.45, fore udder attachment 130.50±1.75° and front teat position 3.61±0.13 cm. these linear type traits mainly affects the longevity and survivability of Sahiwal herds. The most of the traits were found to be intermediate type it leads to increase the longevity and fewer reproductive problems in the Sahiwal herds.

Studies on Ovarian Follicular Dynamics and Steroid Profiles in Sahiwal Cattle

Background: Understanding of ovarian follicular dynamics and endocrine regulation is essential to design and use interventions to optimize reproductive efficiency. Bos indicus and Bos taurus cows have some differences in their follicular dynamics and ovarian steroidal hormones. The present study was planned to understand follicular dynamics vis-a-vis ovarian steroids profiles in Sahiwal cattle. Methods: The study was conducted in normal cyclic, pluriparous, non-lactating Sahiwal cows (n=7). Trans-rectal ultrasonography was performed to record the location, size, number of follicles and size of corpus luteum (CL) from the beginning, till the end of experiment. The dataset was used to characterize the follicular wave emergence, growth, regression, time of selection and ovulation of the dominant follicle in each cow. Result: Three Sahiwal cows showed two wave and four cows showed three wave estrous cycles with mean interovulatory length of 20.33±0.33 and 22.50±0.28 days, respectively. No significant difference was recorded in the maximum diameter of corpus luteum, P4 and E2 plasma levels between 2-wave and 3-wave estrous cycles. The peak progesterone values of 6.00±0.91 and 6.2±1.2 ng/ml and peak estradiol values of 15.83±0.60 and 14.31±0.44 ng/ml were recorded in 2-wave and 3-wave estrous cycle, respectively. The results showed that Sahiwal cows had 2-wave and 3-wave estrous cycle and the 3-wave estrous cycle had comparatively longer inter-ovulatory period and smaller maximum diameter of second wave dominant follicle than 2-wave estrous cycle.

Genome-Wide Scanning for Signatures of Selection Revealed the Putative Genomic Regions and Candidate Genes Controlling Milk Composition and Coat Color Traits in Sahiwal Cattle

BackgroundIn the evolutionary time scale, selection shapes the genetic variation and alters the architecture of genome in the organisms. Selection leaves detectable signatures at the genomic coordinates that provide clues about the protein-coding regions. Sahiwal is a valuable indicine cattle adapted to tropical environments with desirable milk attributes. Insights into the genomic regions under putative selection may reveal the molecular mechanisms affecting the quantitative and other important traits. To understand this, the present investigation was undertaken to explore signatures of selection in the genome of Sahiwal cattle using a medium-density genotyping INDUS chip.ResultDe-correlated composite of multiple selection signals (DCMS), which combines five different univariate statistics, was computed in the dataset to detect the signatures of selection in the Sahiwal genome. Gene annotations, Quantitative Trait Loci (QTL) enrichment, and functional analyses were carried out for the identification of significant genomic regions. A total of 117 genes were identified, which affect a number of important economic traits. The QTL enrichment analysis highlighted 14 significant [False Discovery Rate (FDR)-corrected p-value ≤ 0.05] regions on chromosomes BTA 1, 3, 6, 11, 20, and 21. The top three enriched QTLs were found on BTA 6, 20, and 23, which are associated with exterior, health, milk production, and reproduction traits. The present study on selection signatures revealed some key genes related with coat color (PDGFRA, KIT, and KDR), facial pigmentation (LEF), milk fat percent (MAP3K1, HADH, CYP2U1, and SGMS2), sperm membrane integrity (OSTC), lactation persistency (MRPS30, NNT, CCL28, HMGCS1, NIM1K, ZNF131, and CCDC152), milk yield (GHR and ZNF469), reproduction (NKX2-1 and DENND1A), and bovine tuberculosis susceptibility (RNF144B and PAPSS1). Further analysis of candidate gene prioritization identified four hub genes, viz., KIT, KDR, MAP3K1, and LEF, which play a role in coat color, facial pigmentation, and milk fat percentage in cattle. Gene enrichment analysis revealed significant Gene ontology (GO) terms related to breed-specific coat color and milk fat percent.ConclusionThe key candidate genes and putative genomic regions associated with economic traits were identified in Sahiwal using single nucleotide polymorphism data and the DCMS method. It revealed selection for milk production, coat color, and adaptability to tropical climate. The knowledge about signatures of selection and candidate genes affecting phenotypes have provided a background information that can be further utilized to understand the underlying mechanism involved in these traits in Sahiwal cattle.

Genetic Polymorphism in Prolactin Gene and its Effect on Test Day Milk Production Traits in Sahiwal Cattle

Background: The selection of genetically superior animals at an early stage of life, the molecular markers are used along with traditional selection. The study was carried out to identify the genetic polymorphism in the exon3 region of the Prolactin and enumerate its effect on milk production performance in Sahiwal cattle. Prolactin plays an imperative regulatory role in mammary gland development, milk emission and lactogenesis. Analysed the sequence of this gene to explore whether mutations in this sequence and it could be accountable for quantitative variations in milk production and its composition traits.Methods: Total DNA was isolated from the blood samples of 98 pedigreed Sahiwal population. Using PCR-RFLP method and direct sequencing, noticed a single-nucleotide polymorphism in exon3 region of the Prolactin gene in 156bp and also the effect of non- genetic factors on each trait was assessed by least-squares analysis for non-orthogonal data by a fixed model.Result: PCR-RFLP was done with RsaI restriction endonuclease for the identification of different genotypes. The frequency of G and A alleles of the Prolactin gene was evaluated as 0.575 and 0.425, whereas the frequencies of GG, GA and AA genotypes for the Prolactin gene were 0.45, 0.25 and 0.30, respectively. SNP (G55A) conferred an increase in test-day milk yield around 321.5g, in test day fat yield around 13.9g and in test day SNF yield increase was 19.4g, respectively. High correlation was perceived from test day (TD2) onwards between test day traits and lactation milk yield indicating that selection based on identified SNP in TD2 increased test day milk yield, fat yield and SNF yield by 1.1472 kg, 29.6gm and 45.4gm, respectively.

Molecular characterization of coat color gene in Sahiwal versus Karan Fries bovine

Background Melanocortin-1-receptor gene (MC1R) plays a significant role in signaling cascade of melanin production. In cattle, the coat colors, such as red and black, are an outcome of eumelanin and pheomelanin pigments, respectively. The coat colors have become critical factors in the animal selection process. This study is therefore aimed at the molecular characterization of reddish-brown coat-colored Sahiwal cattle in comparison to the black and white-colored Karan Fries. Results The Sequence length of the MC1R gene was 954 base pairs in Sahiwal cattle. The sequences were examined and submitted to GenBank Acc.No. MG373575 to MG373605. Alignment of both (Sahiwal and Karan Fries) protein sequences by applying ClustalO multiple sequence alignment programs revealed 99.8–96.8% sequence similarity within the bovine. MC1R gene phylogenetic studies were analyzed by MEGA X. The gene MC1R tree, protein confines, and hereditary difference of cattle were derived from Ensemble Asia Cow Genome Browser 97. One unique single-nucleotide polymorphism (c.844C>A) (SNP) was distinguished. Single amino acid changes were detected in the seventh transmembrane structural helix region, with SNP at p.281 T>N of MC1R gene in Karan Fries cattle. Conclusions In this current research, we first distinguished the genomic sequence of the MC1R gene regions that showed evidence of coat variation between Indian indigenous Sahiwal cattle breed correlated with crossbreed Karan Fries. These variations were found in the Melanocortin 1 receptor coding regions of the diverse SNPs. The conclusions of this research provide new insights into understanding the coat color variation in crossbreed compared to the Indian Sahiwal cattle. Graphical abstract

Effect of Growth Hormone-releasing Hormone Gene Polymorphism (GHRH/HAEIII) on First Lactation Milk Yield and Milk Composition Traits in Sahiwal Cattle

Background: Growth hormone-releasing hormone (GHRH), also known as somatoliberin is a releasing hormone of growth hormone (GH). GHRH is a peptide hormone found mainly in the hypothalamus. The gene is significantly associated with increase milk yield in cattle. The objective of this study was to identify the polymorphism in the GHRH gene (GHRH/HaeIII) and to evaluate the relationship between the polymorphism with the breeding values for first lactation milk production and composition traits of Sahiwal cattle reared using PCR-RFLP. Methods: A total of 130 animals were included in the study. PCR-RFLP analysis of each 297bp PCR product was carried out using HaeIII restriction enzyme. The single trait animal model was considered for the estimation of breeding values using WOMBAT software. To study the effect of genotype on the individual trait, PROC GLM (SAS 4.3) was used.Result: PCR-RFLP analysis of GHRH gene revealed three genotypes with genotypic frequencies as; 0.05 (AA), 0.42 (AB) and 0.53 (BB). The allelic frequencies for A and B allele were 0.26 and 0.74, respectively. Sahiwal cows with AA genotype have significantly higher (p less than 0.017) fat percentage in milk while the cows with BB genotype; while the BB genotype cows characterized by significantly higher (p less than 0.025) first lactation 305 day milk yield. Among the three genotypes, BB was most abundant while AA genotype was rarest in the screened Sahiwal samples. The identified potential genetic marker could be used for the development of Marker Assisted Selection (MAS) strategy for higher milk yield and milk composition traits in Sahiwal cattle.

54 Effect of clinical endometritis on the follicle growth dynamics, oocyte recovery, oocyte quality, and invitro developmental competence of oocytes using ovum pickup in Sahiwal cattle

Sahiwal cattle is the premium quality milk breed of cattle in Pakistan. Uterine infections often lead to culling of valuable animals from a herd, resulting in genetic drain. The genetic potential of problematic females could be reaped by invitro embryo production. The objective of the present study was to evaluate the effect of clinical endometritis on follicle growth dynamics, recovery, quality, and invitro developmental competence of oocytes using ovum pickup (OPU) in Sahiwal cattle. The animals, 5–7 years of age, third or fourth parity, and 160 to 170 days in milk (DIM), were inspected for any discharge at the vulva or inside the vagina. Then, B-mode ultrasonography was performed to measure the diameter of cervix and to examine the uterus for the presence of pus. The animals (n=12) were divided into 2 groups: (1) healthy (n=6), and (2) clinical endometritis (n=6), based on the presence or absence of pus at the vulva or in the vagina. The first OPU was performed after 7 days of dominant follicle puncture and subsequently repeated OPUs (54 and 50), after every 7 days over 9 OPU sessions, were performed in the healthy group and clinical endometritis group, respectively. Follicles were aspirated using transvaginal ultrasound–guided needle. Viable COCs were considered for further processing only and were placed in the 100-µL droplets of BO-IVM medium and incubated at 37°C, 5% CO2, and 95% humidity for 24h. Nuclear maturation was estimated by staining the oocytes with Hoechst 33342. Frozen semen from the same Sahiwal bull was thawed and processed for IVF throughout the study. Sperm were prepared using swim-up protocol. Sperm and COCs were co-incubated in 100-µL droplets of BO-IVF for 18h. Finally, presumptive zygotes were cultured in 100-µL drops of BO-IVC medium at 37°C, 5% CO2, 5% O2, and 95% humidity for a period of 7 days. Cleavage rate and blastocyst rate were recorded on Day 2 and 7 following IVF, respectively. The data were analysed using the GLIMMIX procedure of SAS (SAS Institute Inc.). The results revealed that the number of medium-sized follicle (1.32±0.11 vs. 0.56±0.11) and total follicles (9.14±0.70 vs. 6.58±0.72) were higher (P<0.05) in the healthy group than in the clinical endometritis group, respectively. Similarly, the number of oocytes recovered (5.05±0.39 vs. 2.78±0.41), viable oocytes (2.87±0.25 vs. 1.46±0.26), COCs with grade AB, having minimum of 2 cumulus cell layers and homogeneous cytoplasm, (33 vs. 20%) and nuclear maturation (68 vs. 55%) were also higher (P<0.05) in the healthy group than in the clinical endometritis group, respectively. However, cleavage rate (55 vs. 46%) and blastocyst rate (29 vs. 26%) did not differ (P>0.05) between the groups. In conclusion, clinical endometritis has a negative effect on follicle growth dynamics, oocyte recovery, oocyte quality, and nuclear maturation; however, the developmental competence of COCs is not compromised by it.