Genetic diversity and selection in Puerto Rican horses

Since the first Spanish settlers brought horses to America centuries ago, several local varieties and breeds have been established in the New World. These were generally a consequence of the admixture of the different breeds arriving from Europe. In some instances, local horses have been selectively bred for specific traits, such as appearance, endurance, strength, and gait. We looked at the genetics of two breeds, the Puerto Rican Non-Purebred (PRNPB) (also known as the “Criollo”) horses and the Puerto Rican Paso Fino (PRPF), from the Caribbean Island of Puerto Rico. While it is reasonable to assume that there was a historic connection between the two, the genetic link between them has never been established. In our study, we started by looking at the genetic ancestry and diversity of current Puerto Rican horse populations using a 668 bp fragment of the mitochondrial DNA D-loop (HVR1) in 200 horses from 27 locations on the island. We then genotyped all 200 horses in our sample for the “gait-keeper” DMRT3 mutant allele previously associated with the paso gait especially cherished in this island breed. We also genotyped a subset of 24 samples with the Illumina Neogen Equine Community genome-wide array (65,000 SNPs). This data was further combined with the publicly available PRPF genomes from other studies. Our analysis show an undeniable genetic connection between the two varieties in Puerto Rico, consistent with the hypothesis that PRNPB horses represent the descendants of the original genetic pool, a mix of horses imported from the Iberian Peninsula and elsewhere in Europe. Some of the original founders of PRNRB population must have carried the “gait-keeper” DMRT3 allele upon arrival to the island. From this admixture, the desired traits were selected by the local people over the span of centuries. We propose that the frequency of the mutant “gait-keeper” allele originally increased in the local horses due to the selection for the smooth ride and other characters, long before the PRPF breed was established. To support this hypothesis, we demonstrate that PRNPB horses, and not the purebred PRPF, carry a signature of selection in the genomic region containing the DMRT3 locus to this day. The lack of the detectable signature of selection associated with the DMRT3 in the PRPF would be expected if this native breed was originally derived from the genetic pool of PRNPB horses established earlier and most of the founders already had the mutant allele. Consequently, selection specific to PRPF later focused on allels in other genes (including CHRM5, CYP2E1, MYH7, SRSF1, PAM, PRN and others) that have not been previously associated with the prized paso gait phenotype in Puerto Rico or anywhere else.

Partial Results Regarding the Genetic Determinism of Growth Process in a Native Horse Breed using Wither’s Height

Study of variability in domestic animal populations is the foundation of quantitative genetics. Based on statistical methods, the weights of the total phenotype variation that belong to its different fractions (causal components) are quantified: variation due to gene additive effect, variation due to allelic and non-allelic interactions, variation due to environment (general and special), variation due to genotype-environment interaction and possibly variation due to the association between genotype and environment. In this study, during 2017-2020, we used the method of analysis of variance with two sources of variation. The material was represented by 538 individuals from Hucul horse breed analyzed at 18, 30 and 42 months old). The heritability of character was 0.3402±0.1546 (18 months), 0.5549±0.2225 (30 months), 0.4506±0.1895 (42 months), suggest that this is a hereditary condition that follows a quantitative model of inheritance, where the influence of additive genetic factors is moderate to intense. We can conclude that, in this native breed and for this character, a significant share of the phenotypic value is due to the additive effect of genes.

Some External Characteristics of the Gala and Bozakh Sheep Native Breeds and Their Hybrids

In Azerbaijan, sheep mating is natural in both small and large sheep farms and very little attention is paid to the selection process. For industrial crossing of local sheep (western part of the country), five breeding rams of 1.5 years old were purchased in the village of Gala (Absheron) and delivered to the Gaji Tagi farm in the Dashkesan district. Two groups were formed from a native herd of 100 sheep each. Fertilization of females was carried out from October 15 to December 1. According to the indexing data, the external signs of the native breed of Bozakh sheep are better than those of other similar breeds. From the results obtained, it should be concluded that the livestock of Gala and Bozakh breeds can be adapted to the foothills of Azerbaijan.

Impacts of Artificial Insemination on Holstein Cattle Population in Turkey

The use of artificial insemination (AI) is common practice in most countries all around the world, in dairy cattle. AI, which started to be implemented in Turkey in 1930, became more widespread in 1987 in order to rapidly improve the native breed. According to data from 2020, 37% of the cattle population is a crossbred and about 15% of this is Holstein cattle. In the last 5 years, approximately 26.5 million doses of sperm have been imported, in other words, an average of 0.70 doses per milked cow. In this study, the pedigree file records of 5 673 405 Holsteins born from 1975 to 2012, and all sires were known individually were selected for this study. It was determined that 5 673 405 individuals had a total of 11 883 sires. The 10 most used sires are parents of 10.61% of progeny in the population. For today, almost 37% of the cattle population is converted to exotic breeds and their crossbreeds. Approximately 15% of this is Holstein. In the last 5 years, approximately 26.5 million doses of semen have been imported, in other words, an average of 0.70 doses of semen per milked cow. Although frequent use of some sires leads to increased inbreeding in some herds, the consanguinity coefficient in the population was found to be 0.0145. Apart from various problems in insemination practices in Turkey, it can be suggested that an effective way is followed in semen selection and importation.

Estimates of the Economic Cost Caused by Five Major Reproductive Problems in Dairy Animals in Assam and Bihar, India

Reproductive problems in dairy animals reduce fertility, prevent conception, create problems in the delivery of healthy calves, lead to postpartum complications, increase inter-calving periods, reduce milk yield, and lower overall lifetime productivity. This study aimed at understanding the incidence of reproductive problems and the cost caused by these. The study covered 954 dairy animals in Bihar and 1348 dairy animals in Assam that were selected using a multi-stage random sampling method. The costs were calculated as the sum of income losses and expenditures incurred. The major cost incurred resulted from extended calving intervals (46.1% of the total cost), followed by loss through salvage selling (38.1%), expenditure for treatment of repeat breeders (5.9%), loss of milk production (5.3%) and expenditure for extra inseminations (2.0%). About one fifth of the selected reproductive problems were left untreated. The estimated cost of reproductive problems was Indian Rupees (INR) 2424.9 (USD 36.1) per dairy animal per year (of the total dairy animal population) which represented approximately 4.1% of the mean value loss of dairy animals (INR 58,966/USD 877) per year. Reproductive problems were significantly (p < 0.001) higher among improved (exotic breed or cross-bred) dairy animals than indigenous (native breed or nondescript indigenous) dairy animals. The study suggests that with the increase of improved dairy animal population, the loss may further increase. The study concludes that any economic estimation of reproduction problems based on aetiology without confirmatory diagnoses could be highly misleading because of the complex nature of the problems.

Spatio-temporal distribution of bovine leptospirosis in Tamil Nadu and a risk factor analysis

Leptospirosis is a bacterial zoonotic disease that causes abortions, infertility and mastitis in cattle. This research was aimed at investigating the temporal and spatial pattern, sex, age, breed wise distribution of leptospirosis in Tamil Nadu. A seroreactivity of 28.2% was noticed among cattle in seven agro-climatic zones. The temporal trend of leptospirosis recorded during the post-monsoon season (30.5%) was significant when compared to the pre-monsoon season (25.8%). The spatial distribution revealed a high proportion of leptospirosis (31.2%) in the North East zone in comparison with the other zones. The serogroups Australis (37.9%), Hebdomadis (30.6%), Hardjo (29.9%), Javanica (28.1%) and Pomona (19.7%) were predominant in all the agro-climatic zones. The observation of 44.2% seroreactivity in buffaloes is most probably associated with the wallowing behaviour. A high seroreactivity of 31.1% in Holstein Friesian than that compared with the native breed discloses a breed susceptibility. A seroreactivity of 30.2% in animals aged above three years shows an age-related susceptibility, but there was no significant difference between the sexes. The seroreactivity among the animals in an organised farm (33.8%) is higher than in individually reared animals (25.5%) indicating the impact of the rearing system. The three Leptospira strains isolated were identified as the Leptospira interrogans serogroup Australis, Canicola and Sejroe. This study depicted the epidemiology of leptospirosis in cattle and emphasises the need of leptospirosis to be included in cattle health surveillance programmes.

Effects of Adding Eubiotic Lignocellulose on the Growth Performance, Laying Performance, Gut Microbiota, and Short-Chain Fatty Acids of Two Breeds of Hens

Eubiotic lignocellulose is a new and useful dietary fiber source for chickens. However, few studies have been undertaken on the impacts of its use as a supplement in different chicken breeds. In this experiment, 108 Chinese native breed Bian hens (BH) and 108 commercial breed ISA Brown hens (IBH) were chosen. They were randomly divided into three groups, and 0, 2, or 4% eubiotic lignocellulose was added to their feed during the growing periods (9–20 weeks), respectively. We aimed to observe the impacts of adding eubiotic lignocellulose on the growth and laying performance, gut microbiota, and short-chain fatty acid (SCFA) of two breeds of hens. In this study, the addition of eubiotic lignocellulose had no significant effect on the growth performance and gut microbial diversity in the two breeds of chickens (P &gt; 0.05). Compared with the control group, adding 4% eubiotic lignocellulose significantly increased the cecum weight, laying performance (P &lt; 0.05), but had no significant effect on the SCFA of BH (P &gt; 0.05); however, adding 4% significantly inhibited the intestinal development, laying performance, butyrate concentration, and SCFA content of IBH (P &lt; 0.05). Moreover, the relative abundances of the fiber-degrading bacteria Alloprevotella and butyrate-producing bacteria Fusobacterium in the 4% group of BH were significantly higher than those in the 4% group of IBH (P &lt; 0.05), resulting in the concentration of butyrate was significantly higher than those in it (P &lt; 0.05). Combining these results suggests that the tolerance of BH to a high level of eubiotic lignocellulose is greater than that of IBH and adding 2-4% eubiotic lignocellulose is appropriate for BH, while 0–2% eubiotic lignocellulose is appropriate for IBH.

Thyroid and Lipidic Profiles in Nicastrese Goats (Capra hircus) during Pregnancy and Postpartum Period

This study aimed to determine the thyroid and lipid profiles in 30 Nicastrese goats, along different physiological periods: before mating (nonpregnant goats), during the whole pregnancy (pregnant goats), and during postpartum and early lactation (milking goats). Blood samples were collected monthly from March 2020 to January 2021. Serum thyroid-stimulating hormone (TSH), total and free triiodothyronine (T3, fT3), and thyroxine (T4, fT4) concentrations were measured using immunoenzymatic assay kits and serum lipid panels (triglyceride (TG) and total cholesterol (tCho)) by enzymatic colorimetric method; very-low-density lipoprotein cholesterol (VLDL Cho) was calculated. Pregnant and milking goats showed the lower T3 (p < 0.0002) and T4 (p < 0.0005) concentrations, with lower BCS (p < 0.001) only in pregnant ones. Milking goats showed tCho (p < 0.006) concentrations lower than nonpregnant ones, and TG and VLDL Cho (p < 0.001) lower than both pregnant and nonpregnant goats. T4:T3 and T3:fT3 were significantly and positively correlated in both pregnancy and lactation. Under similar environmental, nutrition, and management conditions, different physiological phases play a significant role in the thyroid and lipid profiles in Nicastrese goats. These endocrine and metabolic resources could contribute to the knowledge useful for the salvage of this endangered, local, native breed.