Toll like receptor 4 (TLR4) gene polymorphism and its association with somatic cell score and milk production traits in Indian dromedary camels.

Our study aimed to explore the genetic variation in the Toll-like receptor 4 (TLR4) gene and establish its association with somatic cell score (SCS) and milk production traits in four Indian camel breeds namely Bikaneri, Kachchhi, Jaisalmeri and Mewari. TLR4 gene fragment of 573 bp spanning 5' UTR, exon-1 and partial intron-1 region was amplified and genotyped using the PCR-sequence based typing method. Only one SNP located at position C472T was identified. Genotyping revealed two alleles (C and T) and three genotypes: CC, CT and TT. The genotype frequencies for CC, CT and TT were 0.116, 0.326 and 0.558 and allele frequencies for C and T alleles were 0.279 and 0.721, respectively. Association study inferred that the effect of genotype on SCS, lactation yield (LY) and peak yield (PY) was non-significant however heterozygote (CT) genotypes recorded lower SCS and higher LY and PY. It can be concluded that the TLR4 gene possesses limited genetic variation, depicting polymorphism at a single locus in Indian camel breeds with a predominance of the TT genotype. The association study indicated that heterozygote animals possess better udder health and production performance, the statistical significance of which needs to be established using a large data set.

Performance evaluation of Marwari lambs for growth traits and impact of inbreeding.

This study aimed at the performance evaluation of a closed flock of Marwari sheep and also to study the effect of accumulated inbreeding on the growth traits using a linear mixed model methodology. The data generated for 39 years (1981 to 2020) on Marwari sheep maintained at ICAR-Central Sheep & Wool Research Institute, Arid Region Campus (CSWRI, ARC), Bikaner, Rajasthan, India were used for analysis on growth traits. The overall least-squares means (LSM) of live weights at birth (BWT), weaning (3MWT), 6 months (6MWT), 9 months (9MWT) and 12 months (12MWT) were observed to be 3.02 ± 0.01, 14.30 ± 0.04, 20.12 ± 0.05, 23.68 ± 0.06 and 26.39 ± 0.07 kg, respectively. Overall LSM for average daily gain from birth to 3 months (ADG1), 3 to 6 months (ADG2) and 6 to 12 months (ADG3) were 125.44 ± 0.40, 67.37 ± 0.40 and 35.83 ± 0.29 g/day, respectively. Kleiber ratio (KR) from birth to 3 months (KR1), 3 to 6 months (KR2), and 6 to 12 months (KR3) were 16.78 ± 0.02, 6.58 ± 0.04 and 3.05 ± 0.02, respectively. Results revealed a 4.36, 25.83, 36.33, 31.50 and 28.99% improvement in the live weights since the inception of the improvement programme. This is also reflected by a significant effect of sire on all the growth traits. The estimate of inbreeding in the flock was 1.55%. Highly inbred animals were 5.13% (>5% Fi). The study revealed the non-significant effect of inbreeding level on all growth traits except for BWT and KR3. For BWT, inbreeding classes had variation; however, a negative effect was not seen. The inbreeding class (>5% Fi) was reduced by 0.05 units for KR3 as against its preceding class. Dam's age at lambing and weight influenced the birth weight and subsequent weights. The study concluded that the selection programme of Marwari sheep is in the right direction; however, regular monitoring of inbreeding is necessary and factors affecting growth must be monitored to attain better growth rates in the nucleus.

Udder, teat, and milk vein measurements of Indian dromedary camel and its relationship with milkability traits.

The economic viability of the camel in the current scenario can be ensured by improving its dairy potential. The study on the udder and teat characteristics of dromedary camel and understanding its relationship with milk yield and milkability can be of great value in establishing camel as a dairy animal. The present study was conducted on 45 lactating she-camels of four Indian camel breeds, viz., Bikaneri, Jaisalmeri, Kachchhi, and Mewari, stationed at ICAR-NRCC Bikaner, Rajasthan, India. The udder, teat, and milk vein measurements traits, factors affecting these traits and their relationship with milkability traits, were studied in hand-milked Indian dromedary camel. The means ± S.E. of teat lengths (TL), namely, left fore (LF), left rear (LR), right fore (RF), and right rear (RR), were observed as 52.21 ± 1.66, 58.52 ± 2.11, 50.13 ± 1.74, and 54.37 ± 1.82 mm, respectively. The means ± S.E. of teat diameter (TD), namely, left fore, left rear, right fore, and right rear teat diameters, were observed as 42.44 ± 1.60, 46.01 ± 1.68, 39.29 ± 1.31, and 45.20 ± 1.56 mm, respectively. The means ± S.E for udder depth, udder length, udder height from the ground, milk vein diameter, and milk vein length were observed as 25.44 ± 0.42, 37.29 ± 0.80, 114.80 ± 0.80, 2.02 ± 0.08, and 88.70 ± 0.96 cm, respectively. Udder and milk vein measurements did not differ significantly between breeds. Kachchhi breed has largest teat length and diameter. The breed differences were significant (p ≤ 0.05) for TL-LF, TL-RF, and TD-RR only. The effect of parity was non-significant on udder, teat, and milk vein measurement traits except TD-RR (p ≤ 0.05); however, second parity animals had higher values for all the studied traits except udder height from ground. Positive and highly significant (p ≤ 0.01) correlation of milk yield was observed with the majority of udder, teat, and milk vein measurements, milking time, and milk flow rate, while a negative correlation was found with udder height from ground and milk let-down time. It can be concluded that udder characteristics are influenced by various genetic and non-genetic factors and its relationship with milk yield and milkability can be used for selection and dairy management purposes.

Single Nucleotide Polymorphism in Interleukin-6 and Interleukin-8 Genes of Equines.

In equines, muscle exercise highly affects the expression of genes which are associated with secretion of cytokines. Myokines are the group of cytokines that are produced by skeletal muscles during exercise. Interleukin-6 (IL-6) and Interleukin-8 (IL-8) are among such myokines. This study was therefore taken up in 42 animals of Marwari, Kathiawari, Manipuri and Zanskari horses; and Poitou and Halari donkeys to find out the Single Nucleotide Polymorphisms (SNPs) in the IL-6 and IL-8 genes. Sequence analysis of exon 2 of IL-6 gene revealed an intronic SNP (C>T) at position Equcab3.0:4:54607583 in Poitou donkey. No SNP was detected in the equines covered in the study for IL-6 exon 5, exon 6 and their flanking sequences. However, in exon 1 of the IL-8 gene of all 4 horse breeds and 2 donkey breeds, a non-synonymous SNP (G > C) leading to a change in amino acid from leucine (L) to phenylalanine (F) (p. Leu10> p. Phe10) was observed at position EquCab3.0:3:63720817. Another nucleotide substitution was T>C in the intron 1-2 of IL-8 gene in all equids studied at position EquCab3.0:3:63720770. In addition to above two substitutions, in the 5' UTR of IL-8 gene in Poitou donkey, in place of guanosine (G), heterozygous condition S (C/G) was observed at position EquCab3.0:3: 63720883. This paper presents four SNPs with one non-synonymous SNP leading to a change in IL-8 protein sequence in equines.

Genetic parameter estimates for reproductive traits in Chokla ewes of India.

Early selection of ewes for better reproductive performance may reduce generation interval and increase genetic gains. Considering this, the present study aimed to derive the genetic parameter estimates of ten reproductive traits in 1172 maiden Chokla ewes over a period of 22 years. Initially, the traits, namely age at first service (AFS), weight at first service (WFS), age at first successful service (ASS), weight at first successful service (WSS), age at first lambing (AFL), ewe's weight at first lambing (WFL), first lambing interval (LI1), first service period (SP1), first parity lamb survival (SUR1) and first service fertility rate (FER1) were analysed for the effects of genetic and non-genetic factors. The significant effects were fitted into six animal models to estimate the genetic parameters. The heritability estimates were low for the age traits and FER1 (0.06-0.09) but moderate for the rest of the traits (0.16-0.23), indicating the suitability of these traits for improvement through direct selection. The maternal direct and permanent effects were meagre for all the traits. The ewe weights had strongly negative correlations with the age of sexual maturity and positive correlations with lamb survival. The results emphasise the need to optimize the weights of maiden ewes to improve reproductive performance.

Genetic and non-genetic factors affecting morphometry of Sirohi goats.

AIM: The aim was to estimate genetic and non-genetic factors affecting morphometric traits of Sirohi goats under field condition. MATERIALS AND METHODS: The detailed information of all animals on body measurements at birth, 3, 6, 9, and 12 months of age was collected from farmer's flock under field condition born during 2007-2013 to analyze the effect of genetic and non-genetic factors. The least squares maximum likelihood program was used to estimate genetic and non-genetic parameters affecting morphometric traits. RESULTS AND DISCUSSION: Effect of sire, cluster, year of birth, and sex was found to be highly significant (p<0.01) on all three morphometric traits, parity was highly significant (p<0.01) for body height (BH) and body girth (BG) at birth. The h(2) estimates for morphometric traits ranged among 0.528±0.163 to 0.709±0.144 for BH, 0.408±0.159 to 0.605±0.192 for body length (BL), and 0.503±0.197 to 0.695±0.161 for BG. CONCLUSION: The effect of sire was highly significant (p<0.01) and also h² estimate of all morphometric traits were medium to high; therefore, it could be concluded on the basis of present findings that animals with higher body measurements at initial phases of growth will perform better with respect to even body weight traits at later stages of growth.