Random regression model estimation of genetic parameters for show-jumping results of Hungarian Sporthorses.

The aim of this study was to estimate the genetic parameters for show-jumping competition performance of Hungarian Sporthorses using a random regression model. There were 21,210 records from 739 horses collected in Hungary between 1996 and 2004. Performance was expressed as shifted Blom normalized ranks and as the difference between fence height and fault points. The random regression model (RRM) included fixed effects for sex, year, location, and obstacle height and random effects for animal, rider and permanent environment. Regressions for the random effects in the RRM were modelled with Legendre polynomials from first to fifth order of fit. The model focused on performance of horses from 4 to 11 years of age, with heterogeneous residual variances considered. The heritabilities were low to moderate for both variables. Genetic and phenotypic correlations between different ages decreased with increasing distance between the ages.

Economic weights of production and functional traits for Holstein-Friesian cattle in Hungary.

A bio-economic model was used to estimate economic values of 15 milk production, functional, growth and carcass traits for Hungarian Holstein-Friesian cattle. The calculations were carried out for the situation in Hungary from 2000 to 2007, assuming no production quotas. The marginal economic values were defined as partial derivatives of the profit function with respect to each trait in a production system with dairy cow herds and with sales of surplus male calves. The economic weights for maternal and direct components of traits were calculated multiplying the marginal economic values by the number of discounted expression summed over a 25-year investment period for 2-year-old bulls (candidates for selection). The standardized economic weight (economic weight x genetic standard deviation) of the trait or trait component expressed as percentage of the sum of the standardized economic weights for all traits and trait components represented the relative economic importance of this trait or trait component. The highest relative economic importance was obtained for milk yield (25%), followed by productive lifetime of cows (23%), protein yield and the direct component of a cow's total conception rate (9% each), the maternal effect of the total conception rate of cows and the somatic cell score (approximately 7% each), fat yield (5%) and mature weight of cows and daily gain in rearing of calves (approximately 4% each). Other functional traits (clinical mastitis incidence, calving difficulty score, total conception rate of heifers and calf mortality) reached a relative economic importance between 0.5% and 2%. Birth weight and dressing percentage were least important (<0.5%). Based on these results, the inclusion of productive lifetime and cow fertility in the breeding programme for Holstein-Friesian cattle in Hungary is advisable.

Searching for DNA markers for milk production and composition on chromosome 6 in sheep.

Several milk protein polymorphisms are potential tools for selection in dairy ruminants. However, research results for dairy sheep are not as conclusive as those for goats or cattle and are often controversial. The main objective of this study was to find and later use molecular genetic markers in selection to improve milk production and milk composition in Awassi ewes. Chromosome 6 was chosen because several studies have reported the presence of significant quantitative trait loci (QTL) affecting milk production traits on ovine and bovine chromosome 6. Altogether, genotypes for 13 microsatellite loci were determined for 258 ewes, which were purebred Awassi or Awassi-Merino crosses. Phenotypic data were lactation yield of milk, milk fat, protein and lactose (kg), average milk protein and fat percentage and average somatic cell count. Five out of the 13 microsatellites showed significant association with at least one of the examined traits.

Effect of MYOG genotypes on growth rate and production traits in Hungarian large white pigs.

The effect of the porcine myogenin (Myog) 3' polymorphism on birth weight, growth rate, carcass weight, lean weight, lean meat percentage and back-fat thickness has been investigated in Hungarian Large White pigs. MYOG genotypes were determined by PCR-RFLP assay. The obtained MYOGA frequency value was 0.6275. Due to the small number of BB piglets the effect of the MYOG genotypes on birth weight was not significant; however, an increasing tendency was observed from genotype AA to BB. The growth rate difference between MYOG genotypes was significant: BB animals showed the highest growth rate values during the fattening period. Since few results are available on the possible use of MYOG gene polymorphism in selection to improve carcass and growth traits, by this study the authors hope to provide additional data on this particular subject.

Influence of porcine coat colour genotypes on haematological parameters, piglet birth weight and body weight gain until weaning.

Two F2 generations of an intercross between Hampshire boars and Hungarian Large White sows were produced to estimate the effects of the porcine KIT genotypes (II, Ii and ii) on quantitative and qualitative haematological indices, on piglet birth weight and growth performance until weaning. Piglets carrying the I allele had significantly fewer lymphocytes (p = 0.041) than the ii homozygotes, heterozygotes had measures between the two homozygotes. KIT genotypes did not influence white blood cells, red blood cells, haemoglobin and haematocrite. II genotype piglets were significantly lighter at birth than the ones carrying the recessive i allele, the effect of KIT genotypes on gain until weaning was not significant, but II piglets tended to gain less. The results of this study support the hypothesis of M. Johansson, H. Ellegren, L. Marklund, U. Gustavsson, E. Ringmar-Cederberg, K. Andersson, I. Edfors-Lilja and L. Andersson [(1992) Genomics, 14, 965] that the pleiotrophic effect of the porcine KIT mutations on haematopoietic cells must be mild.

Heritabilities and additive genetic variances of the activities of some enzymes in Drosophila melanogaster populations living in different habitats.

Drosophila melanogaster samples were collected from a large population in two habitats: farmyards and distilleries. Samples were taken from two villages in each habitat. Three isofemale lines were established from all four samples and full-sib crosses were set in each isofemale line. Activities of four enzymes (ADH, alpha GPDH, IDH and 6PGDH) were measured in the offspring of each cross on starch gel after electrophoresis. Broad sense heritabilities and additive genetic variances were estimated in all four samples. Most of the activity variation was observed within the isofemale lines. The isofemale lines tended to be more different in the distilleries than in the farmyards. There was no significant difference in the average activities between the two habitats for any of the enzymes investigated. The additive genetic variance of the enzyme activities did not exhibit a consistent habitat pattern. In the farmyard habitat, we detected a higher activity variation in Tiszafüred than in the other village. Strong correlation was observed among the activities of the enzymes investigated. Correlation coefficients indicated higher level of correlation in the samples collected in Tiszafüred than in those originating from Tiszaszolos. The heritability values were rather high and they had a considerable variation both between the habitats and across the enzymes.

Repeatability and heritability of ovulation number and embryos in dam-daughters pairs in superovulated Holstein-Friesian cows.

Holstein-Friesian dams (n = 28) and daughters (n = 28) were superovulated (total number of observations was 235) to determine the repeatability and heritability of ovulation number and embryo collection result for FSH treatment. The donor cows were superovulated with FSHp, artificial insemination was performed and embryo collection was carried out 7 days later. For the analysis, the raw corpdata of the number of corpora lutea (CL), the number of collected embryos (EM) and their log-transformed values were used (log CL, log EM). The genetic parameters were calculated by using the VCE4 software. For calculating heritability, the number of embryo collection was used as a random effect; for calculating repeatability, the permanent environment was fitted. The additive genetic variance of CL was 8.91 and that of the EM was 9.23. The additive genetic variance for the log CL and log EM were 0.457 and 0.340, respectively. The estimated heritability for CL and EM were 0.234 and 0.159, and repeatability were 0.386 and 0.301, respectively. Higher heritabilities but lower as the previous repeatabilities were observed for the log-transformed data, 0.266, 0.194 and 0.294, 0.208 for log CL and for log EM, respectively.