Dubravko Škorput

Carcass quality of crossbred pigs with Pietrain as a terminal sire

Abstract The aim of this paper was to investigate the effect of the crossbreed and halothane genotype on carcass quality traits of fatteners from commercial pig farm. Study was carried out on 68 crossbred pigs divided into two groups according to sow genotype: Large Whitex Swedish Landrace (LWxSL) and Large White x German Landrace x (LWxGL). Both sow genotypes were mated with Pietrain (P) as a terminal sire. Influence of crossbreeding and halothane genotype on cold carcass weight, carcass length, dressing percentage and lean percentage, slaughter line measurements as well as fat and M. Longissimus dorsi areas were not significant (P>0.05). The value of pH45 measured in M. Longissimus dorsi was higher in Px(LWxGL) crossbreeds and dominant homozygote genotype (P<0.05). Measurements of pH24 were not significantly different (P>0.05) between crossbreeds and halothane genotypes. Except for pH45 value, most of other measured carcass quality traits were not affected by crossbreeding combination and halothane genotype (P>0.05).

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.

Effect of breed and rearing system on intramuscular fatty acid profile of M. Semimembranosus in raw Slavonian ham

Abstract The effects of breed and rearing system on fatty acid (FA) profile of M. Semimembranosus in raw Slavonian ham were evaluated. Forty pigs were grouped by breed (Black Slavonian (BS) vs. Black Slavonian x Duroc (BSxD)) and by rearing system (outdoor vs. indoor), 10 pigs per group. All of the saturated FA (SFA) and monounsaturated FA (MUFA) significantly affected by genotype showed smaller values in the intramuscular fat of BS than of BSxD pigs. The percentage of polyunsaturated FA (PUFA) was higher in BS pigs than BSxD pigs. The PUFA/SFA and n-6/n-3 ratios were more favourable in BS pigs. Within SFA and MUFA, only C16:1 and C18:0 were affected by rearing system. On the other hand, rearing system influenced most of the PUFA, but without clear effect on PUFA/ SFA and n-6/n-3 ratios.

Partition of genetic trends by origin in Landrace and Large-White pigs

The objective of this study was to analyse the effectiveness of genetic improvement via domestic selection and import for backfat thickness and time on test in a conventional pig breeding programme for Landrace (L) and Large-White (LW) breeds. Phenotype data was available for 25 553 L and 10 432 LW pigs born between 2002 and 2012 from four large-scale farms and 72 family farms. Pedigree information indicated whether each animal was born and registered within the domestic breeding programme or has been imported. This information was used for defining the genetic groups of unknown parents in a pedigree and the partitioning analysis. Breeding values were estimated using a Bayesian analysis of an animal model with and without genetic groups. Such analysis enabled full Bayesian inference of the genetic trends and their partitioning by the origin of germplasm. Estimates of genetic group indicated that imported germplasm was overall better than domestic and substantial changes in estimates of breeding values was observed when genetic group were fitted. The estimated genetic trends in L were favourable and significantly different from zero by the end of the analysed period. Overall, the genetic trends in LW were not different from zero. The relative contribution of imported germplasm to genetic trends was large, especially towards the end of analysed period with 78% and 67% in L and from 50% to 67% in LW. The analyses suggest that domestic breeding activities and sources of imported animals need to be re-evaluated, in particular in LW breed.

Fixed effects in models for the genetic evaluation of backfat thickness and time on test in gilts

Abstract Fixed effects in the model for backfat thickness and the time on test were evaluated. Data records from large scale farm in period from January 1998 to December 2007 were analyzed. Two models were developed. Fixed effects of genotype, season and weight were included in the model for backfat thickness. The model for time on test was simpler than model for backfat thickness, containing only fixed effects of genotype and season. Choice of the model was based on coefficient of regression and degrees of freedom. The model for backfat thickness explained 56% of the variability, while the model for time on test explained 65% of variability. The results of this investigation will be useful in future development of the model for prediction of breeding values for gilts in field test.