Vesna Pavić

The genetic diversity and structure of 18 sheep breeds exposed to isolation and selection

The phylogenetic layout of the genotyped (30 microsatellite) 18 sheep breeds in this study demands and provides the opportunity to evaluate both neutral and adaptive components of genetic diversity in a naturally and artificially selected and subdivided sheep population. Seven Pramenka strains from Bosnia and Herzegovina and Croatia characterized by a very low intensity of artificial selection, preserved the highest neutral genetic variability. Eight central and north-western European breeds under considerable artificial isolation and selection preserved the lowest genetic variability. Only combinations of various phylogenetic parameters offer a reasonable explanation for underlying evolutionary forces working in the investigated island and mainland sheep breeds under variable natural and artificial selection. More than 60% of total genetic, diversity was allocated to virtually unselected Pramenka strains, and an additional 25% to native moderately selected Graue Gehoernte Heidschnucke and intensively selected Ostfriesische Milchschafe. Some economically very important breeds and strains did not contribute to a pool with maximal genetic diversity, while they play an important role in the cultural heritage of respective countries.

Genetic diversity measures of the Croatian Spotted goat.

In the present study, microsatellite data of 20 loci were generated and utilized to evaluate genetic variability of the Croatian Spotted goat. Genetic variability was high, with means for expected gene diversity of 0.771, observed heterozygosity of 0.759, and 8.1 for the total number of alleles per locus. There are no indications for deviations from random breeding within the population. Level of inbreeding was only 2% and non-significant. The population was found to deviate significantly under infinitive allele model (IAM) and two phase model (TPM), while stepwise mutation model (SMM) and qualitative mode-shift test of allele frequencies indicate the absence of genetic bottleneck in the recent past in the population of the Croatian Spotted goat. High level of genetic diversity, as it is presented in this study, may be seen as an initial guide for conservation decisions in the future.

Effect of breed on mineral composition of meat from light lambs

Abstract The proximate composition and mineral content of light lambs muscle (derived from Istrian and Dalmatian Pramenka breeds) were studied. The M. Longissimus dorsi (MLD) samples of 30 carcasses were analysed and the effects of breed and sex were studied. Although lambs of investigated breeds were similar for slaughter age (2.5 months), Dalmatian Pramenka had significantly higher carcass weights (CW; P<0.05). Breed had a significant influence on moisture and fat contents, whilst mineral composition (with the exception of selenium) was scarcely affected by breed and sex. Fat and moisture contents were significantly correlated with cold CW. The magnesium, calcium, manganese and selenium contents were significantly correlated (r=0.50, -0.46, 0.44, 0.54; P<0.05 respectively) with CW. This study contributes to characterization of lamb carcasses from Istrian Sheep and Dalmatian Pramenka breeds and provides new data on the composition of the MLD of light lambs.

Estimation of genetic parameters and genetic trends for reproductive traits in Saanen goats.

The study was conducted on Saanen goats raised in Croatia. The object of the study was to determine the average litter size (LS), birth weight (BW) and total litter weight (TLW). The study included a total of 2 500 goats among which 1 786 were phenotyped. A total of 6 349 records for BW and 4 256 records for LS and TLW were used in descriptive and inferential statistical analysis. Determined averages for LS, BW and TLW were 1.74 lambs, 3.27 kg and 5.65 kg, respectively. Twinning and tripling rates were 36.9% and 6.2%. Single-trait analysis under repeatability animal model was used in estimation of variance components and prediction of breeding values. Season (as year-month interaction), age at lambing (as quadratic regression) nested within parity and type of birth were treated as fixed, while herd-year, additive genetic, permanent environmental and residual were treated as random effects, respectively. Investigated environmental effects significantly affected all reproductive traits (p<0.001). The largest phenotype variability among investigated traits was determined for TLW. Additive genetic effect accounted for 7%, 5% and 4% in total variability for LS, BW and TLW, respectively. Genetic trends of reproductive traits were estimated for the period from year 2000 to 2010. A positive genetic trend was determined for LS, a negative genetic trend for BW and genetic stagnation for TLW.