Journal of Animal Science and Technology (JAST) is a peer-reviewed, open access journal publishing original research, review articles and notes in all fields of animal science. Topics covered by the journal include: genetics and breeding, physiology, nutrition of monogastric animals, nutrition of ruminants, animal products (milk, meat, eggs and their by-products) and their processing, grasslands and roughages, livestock environment, animal biotechnology, animal behavior and welfare.

We used data collected on 48,739 cows from 1982 to 2013 from Foka farm in the Isfahan province of Iran to assess the reasons for culling in Iranian Holstein dairy cattle in the context of breeding values of economic traits, and also to study the relationship between longevity and production traits. Estimation of (co)variance components and genetic parameters for studied traits including MY, FY, herd life (HL) and length of production life (LPL) was by AI-REML algorithm in WOMBAT software. The results showed that 27.11% of cows were culled voluntarily under the farmers’ command. The number and reasons for culling animals varied considerably over the years. Also, the results showed that involuntarily culled animals were valuable with significantly higher breeding values for MY and FY (P < .0001) than those of voluntarily culled individuals. The estimates of heritability for longevity traits (HL and LPL) were low (0.11 and 0.09), but their genetic correlation with production traits were high and positive (0.63–0.70). Our results suggest that some opportunity may exist for genetic improvements in fat and milk yield in Iranian Holsteins.

Milk yield (MY) is highly heritable and an economically important trait in dairy livestock species. To increase power to detect candidate genomic regions for this trait, we carried out a meta-analysis of genome-wide association studies (GWAS). In the present study, we identified 19 studies in PubMed for the meta-analysis. After review of the studies, 16 studies passed the filters for meta-analysis, and the number of chromosomes, detected markers and their positions, number of animals, and p-values were extracted from these studies and recorded. The final data set based on 16 GWAS studies had 353,698 cows and 3950 markers and was analyzed using METAL software. Our findings revealed 1712 significant (p-value < 2.5 × 10⁻⁶) genomic loci related to MY, with markers associated with MY found on all autosomes and sex chromosomes and the majority of them found on chromosome 14. Furthermore, gene ontology (GO) annotation was used to explore biological functions of the genes associated with MY; therefore, different regions of this chromosome may be suitable as genomic regions for further research into gene expression.

DNAJA1 or heat shock protein 40 (Hsp40) is associated with heat adaptation in various organisms. We amplified and sequenced a total of 1,142 bp of bovine Hsp40 gene representing the critical N-terminal (NTR) and C-terminal (CTR) regions in representative samples of African, Asian and American cattle breeds. Eleven and 9 different haplotypes were observed in the NTR in Asian and African breeds respectively while in American Brangus, only two mutations were observed resulting in two haplotypes. The CTR appears to be highly conserved between cattle and yak. In-silico functional analysis with PANTHER predicted putative deleterious functional impact of c.161 T>A; p. V54Q while alignment of bovine and human NTR-J domains revealed that p.Q19H, p.E20Q and p. E21X mutations occurred in helix 2 and p.V54Q missense mutation occurred in helix 3 respectively. The 124 bp insertion found in the yak DNAJA1 ortholog may have significant functional relevance warranting further investigation. Our results suggest that these genetic differences may be concomitant with population genetic history and possible functional consequences for climate adaptation in bovidae.

Goats make up the largest group of ruminant livestock in Nigeria and are strategic in bridging animal protein supply gap and improving the economy of rural households. The hypervariable region 1 (HVR1) of the caprine mitochondrial genome was investigated to better understand genetic diversity important for improving selection for animal breeding and conservation programs. We sequenced and analysed the mitochondrial DNA (mtDNA) HVR1 in 291 unrelated indigenous Nigerian goats (West African Dwarf (WAD), Red Sokoto (RSO) and Sahel (SAH)), randomly sampled from around the country, and compared them with the HVR1 sequences of 336 Indian goats and 12 other sequences in five different species in the genus Capra (C. falconeri, C. ibex nubiana, C. aegagrus, C. cylindricornis and C. sibirica). A total of 139 polymorphic sites from 291 individuals were captured in 204 haplotypes. Within and among population variations were 77.25 and 22.74 percent, respectively. Nigerian goats showed high genetic diversity (0.87) and high FST values, and separate from Indian goats and other wild species. Haplogroups in WAD separates it from RSO and SAH concomitant with a different demographic history. Clear genetic structure was found among Nigerian goat breeds with appreciable variation in mtDNA HVR1 region. This study grouped Nigerian goat breeds into two major groups suggesting two different demographic origins for Northern and Southern breeds. High genetic admixing denotes different maternal origins and in contrast to evidence from goats from Levant and Central Asia, where goats were originally domesticated. Les caprins constituent le plus grand groupe de ruminants domestiques au Nigéria et jouent un rôle stratégique dans l'approvisionnement en protéines animales et dans l'amélioration de l'économie des ménages ruraux. Une recherche a été menée à propos de la région hypervariable 1 (HVR1) du génome mitochondrial caprin dans le but de mieux comprendre l'importance de la diversité génétique pour améliorer la sélection dans les programmes d'amélioration génétique et de conservation des animaux. La région hypervariable 1 de l'ADN mitochondrial (HVR1) a été séquencée et analysée chez 291 chèvres indigènes du Nigéria, sans rapport entre elles (Naine d'Afrique Occidentale (NAO), Rouge de Sokoto (RS) et Sahel (S)), échantillonnées de manière aléatoire à travers le pays et comparées avec les séquences HVR1 de 336 chèvres indiennes et avec 12 autres séquences de 5 espèces différentes du genre Capra (C. falconeri, C. ibex nubiana, C. aegagrus, C. cylindricornis et C. sibirica). Un total de 139 sites polymorphes de 291 individus a été rassemblé en 204 haplotypes. La variation intra- et inter-populationnelle a été de 77,25 pour cent et de 22,74 pour cent, respectivement. Les caprins nigérians ont montré une grande diversité génétique (0,87) et des valeurs de FST élevées et différentes de celles des chèvres indiennes et de celles des autres espèces sauvages. D'après les haplogroupes, la chèvre NAO serait à séparer des populations concomitantes de RS et S avec une histoire démographique différente. Une structure génétique claire a été décelée entre les races caprines du Nigéria, avec une variation substantielle dans la région HVR1 de l'ADN mitochondrial. Cette étude a regroupé les races caprines nigérianes en deux groupes principaux, ce qui suggère deux origines démographiques différentes pour les races du Nord et du Sud. Le fort degré de mélange génétique dénote des origines maternelles différentes, contrairement à ce qui a été observé chez les chèvres du Levant et d'Asie Centrale, où les caprins furent d'abord domestiqués. Las cabras constituyen el mayor grupo de ganado rumiante en Nigeria y desempeñan un papel estratégico en el aporte de proteína animal y en la mejora de la economía de los hogares rurales. Se investigó acerca de la región hipervariable 1 (HVR1) del genoma mitocondrial caprino con el fin de comprender mejor la importancia de la diversidad genética para mejorar la selección en los programas de mejora y conservación animal. Se secuenció y se analizó la región hipervariable 1 del ADN mitocondrial (HVR1) en 291 cabras autóctonas de Nigeria no relacionadas (Enana de África Occidental (EAO), Roja de Sokoto (RS) y Sahel (S)), seleccionadas aleatoriamente a lo largo del país y comparadas con las secuencias HVR1 de 336 cabras indias y con otras 12 secuencias de 5 especies diferentes del género Capra (C. falconeri, C. ibex nubiana, C. aegagrus, C. cylindricornis y C. sibirica). Un total de 139 sitios polimórficos de 291 individuos se concentraron en 204 haplotipos. La variación intra- e interpoblacional fue de 77,25 por ciento y de 22,74 por ciento, respectivamente. Las cabras nigerianas mostraron una elevada diversidad genética (0,87) y unos valores de FST elevados, distintos de los de las cabras indias y de los de las otras especies salvajes. De acuerdo con los haplogrupos, la cabra EAO se desliga de poblaciones concomitantes de RS y S con una historia demográfica diferente. Se identificó una estructura genética clara entre las razas caprinas de Nigeria, con una variación apreciable en la región HVR1 del ADN mitocondrial. Este estudio...