Jitka Schmidová

Genetic diversity within and gene flow between three draught horse breeds using genealogical information

Three draught horse breeds are maintained in the Czech Republic: the Silesian Noriker (SN), the Noriker (N), and the Czech-Moravian Belgian (CMB). Because the SN and CMB populations are currently closed to outside breeding and are endangered (Genetic Resources), the loss of the genetic variation these horses represent is concerning. Genetic diversity within and between these three breeds and their population structures was analyzed based on pedigree information. Our goal was to identify and quantify factors that affected their genetic variability. The effective population size was analyzed in each breed. The numbers of generations were 22, 32, and 32 for the SN, N, and CMB breeds, respectively, with average equivalent known generations of 9.81, 8.45, and 8.91, respectively. The effective numbers of founders and ancestors contributing to the current genetic pool were, respectively, 69.42 and 22.32 for the SN breed, 98.48 and 42.20 for the N breed, and 43.33 and 23.32 for the CMB breed. The average inbreeding coefficients were 4.6%, 2%, and 4% for the SN, N, and CMB breeds, respectively, and the average inbreeding rate was 0.5% for the SN and CMB breeds and 0.2% for the N breed. The corresponding estimates of effective population size were 95, 195, and 101 for the SN, N, and CMB breeds, respectively. These statistics suggest that the genetic variability has decreased, and without changes in breeding strategy the genetic variability might continue to decline. Using genealogical F-statistics, small genetic differences were identified between the analyzed populations (FST = 0.02).

Effect of dietary supplementation with preparation comprising the blend of essential oil from Origanum vulgare (lamiaceae) and Citrus spp. (citraceae) on coccidia invasion and lamb growth

Abstract The objective of this research was to assess the effectiveness of dietary supplementation with oils extracted from Origanum vulgare (Lamiaceae) and Citrus spp. (Citraceae) against coccidia and to determine the impact on lamb growth in an indoor housing system. A total of 222 ewes and 276 lambs of the Polish Lowland Sheep breed maintained indoors under the same environmental conditions were included in the study. Four-month pregnant ewes were divided into three treatment groups following parasitological evaluation. Experimental diets were supplemented with containing vegetal extracts of O. vulgare and Citrus spp. During the study, parasitological analyses and assessments of lamb growth were conducted. In vivo evaluation of lamb muscularity and fatness was performed at 100 days of age. The inclusion of the preparation containing the essential oil blend of O. vulgare and Citrus spp. in the diet of sheep resulted in decreases in both the intensity and prevalence of coccidian infection within the flock as well had influence increases in lamb growth. Therefore, this dietary supplement may contribute to the improved profitability of sheep farming through increased production efficiency and the production of higher-quality meat.

Comparison of models to estimate genetic parameters for scores of competitive sport horse events in the Czech Republic

The objective of the present study was to estimate genetic parameters and predict breeding values of sport horses in the Czech Republic using animal model variations. The data set for the evaluation was com - posed of edited records of show jumping competitions in the Czech Republic in years 1991-2013. Input data were not normally distributed; hence Blom transformation was used for the variable filtration. The Gibbs sampling algorithm was used for the genetic parameters estimation. Two models were examined. The first was a random regression model including the effect of a horses experience in competition (expressed as the length of the horses sporting career in days), fixed effects of sex, age, and event, and random effects of rider, permanent environment, and animal. The second model was a multi-trait model with fixed effects for sex, age, and event and random effects for rider, permanent environment, and animal. In this latter case, horse performance was classified as three traits. The first trait was jumping results from obstacle heights of 90-110 cm, the second of 120-135 cm, and the third of 140-155 cm. In the random regression model, heritability estimates ranged from 0.01 to 0.11; whereas in the multi-trait model, heritabilities were 0.07, 0.11, and 0.14 for the first, second, and third trait, respectively. Results indicate that both models could be used to predict breeding values of sport horses in the Czech Republic. The multi-trait model revealed that heritability estimates increased with the increasing height of obstacle. In the random regression model, breeding values differed according to a horses experience in competition, allowing adjustment of the breeding value for the environmental effect of a past experience.

Variance components, heritability estimates, and breeding values for performance test traits in Old Kladruber horses

The Old Kladruber horse is an important Czech genetic resource. In the current study, two categories of traits were evaluated – the first, a numerical score for Type and Gender Expression and the second, 11 traits describing performance divided into four categories: (1) Rideability (Overall Impression, Rideability), (2) Gaits (Walk, Trot, Canter), (3) Carriage Drivability (Dressage Test, Obstacle Driving Test, Marathon Test), and (4) Reliability in Tug (First Tug, Second Tug, Third Tug). The original data set contained records from 700 individuals from the period 1995–2014, each horse having 3–5 performance evaluations for the suite of traits. Our objective was to identify a suitable model for the estimation of genetic parameters and prediction of breeding values. Only one model was examined for the Type and Gender Expression trait, whereas three models were compared for the analysis of each performance trait. Criteria for choosing the most appropriate model were minimal values for the deviance information criterion (DIC) statistics, low ratios of residual variance to phenotypic variance, and maximal heritability estimates. The heritability estimate for Type and Gender Expression was 0.18. For the performance traits, the model with the fewest sources of variation (model 1) was more appropriate than two alternatives with more sources of variation. Heritability estimates from this model ranged from 0.08 to 0.40, while estimates for various performance traits from the other models were in the range 0.08–0.24. Low heritabilities for several of the performance traits suggested that selection for their genetic improvement would likely be unsuccessful. In order to maintain genetic variability, inbreeding, and fitness in the Old Kladruber population we suggest to use breeding value estimation using the heritabilities and the method presented in this paper.