Test-day data for daily milk yield and fat, protein, and lactose content were sampled from the years 1988 to 2003 in 17 flocks belonging to 2 genetically well-tied buck circles. In total, records from 2,111 to 2,215 goats for content traits and 2,371 goats for daily milk yield were included in the analysis, averaging 2.6 and 4.8 observations per goat for the 2 groups of traits, respectively. The data were analyzed by using 4 test-day models with different modeling of fixed effects. Model [0] (the reference model) contained a fixed effect of year-season of kidding with regression on Ali-Schaeffer polynomials nested within the year-season classes, and a random effect of flock test-day. In model [1], the lactation curve effect from model [0] was replaced by a fixed effect of days in milk (in 3-d periods), the same for all year-seasons of kidding. Models [2] and [3] were obtained from model [1] by removing the fixed year-season of kidding effect and considering the flock test-day effect as either fixed or random, respectively. The models were compared by using 2 criteria: mean-squared error of prediction and a test of bias affecting the genetic trend. The first criterion indicated a preference for model [3], whereas the second criterion preferred model [1]. Mean-squared error of prediction is based on model fit, whereas the second criterion tests the ability of the model to produce unbiased genetic evaluation (i.e., its capability of separating environmental and genetic time trends). Thus, a fixed structure with year (year, year-season, or possibly flock-year) was indicated to appropriately separate time trends. Heritability estimates for daily milk yield and milk content were 0.26 and 0.24 to 0.27, respectively.

This study was aimed at analysing single-nucleotide polymorphisms in the oestrogen receptor 1 (ESR1) and retinol-binding protein 4 (RBP4) genes in a hyperprolific line of Landrace × Large White (Topigs 20) cross sows (n = 101). The following litter size traits were analysed: total number born, number of born alive and number of weaned piglets. ESR1 and RBP4 genotypes determined on the basis of single-nucleotide polymorphisms were analysed using the least square method with the GLM procedure in SAS with eight effects. The REG procedure was used to calculate the effects of the additive and dominance components. The second parity sows with ESR1 BB genotype had a significantly higher (P < 0.05) number of weaned piglets compared to AB, with a tendency towards difference (P < 0.1) between homozygotes for number of born alive and number of weaned piglets. In the case of the RBP4 gene, the first parity sows of the AA genotype had a significantly higher total number born (P < 0.05) compared with the BB genotype, with a tendency towards difference (P < 0.1) between AA and heterozygotes for total number born, and homozygotes for number of born alive. The BB genotype showed a tendency for higher number of weaned piglets (P < 0.1) as compared with the AA genotype in the third parity sows for the RBP4 gene. In all parities, significant effects (P < 0.05) of parity were recorded for total number born, number of born alive and number of weaned piglets, season of farrowing for total number born, and the ESR1 and RBP4 interaction for number of born alive. In the first parity sows, significant effects (P < 0.05) on total number born were determined for gene interaction and gestation length, the latter also being recorded in the second parity sows. The additive (a) effect of single-nucleotide polymorphisms in RBP4 was significant (P < 0.05) for total number born in all parities as well as in the first parity sows, and dominance effect (d) (P < 0.05) of single-nucleotide polymorphisms in ESR1 for number of weaned piglets in the third parity sows. The obtained results regarding the investigated genes could help to provide a better understanding of the effect of single-nucleotide polymorphisms on litter size and thus promote genetic progress in pig reproduction management.

The objective of the present study was to identify the Prolactin Receptor (PRLR) gene polymorphism related to litter size traits. The study included 101 Topigs 20 line of sows with 426 litters. The traits studied were: Total Number of Born (TNB), Number of Born Alive (NBA), Number of Still Born (NSB), and Number of MUMmifi ed (NMUM) piglets. Polymorphism was identifi ed with the polymerase chain reactionrestriction fragment length polymorphism method. Allelic and genotype frequencies and deviation from Hardy-Weinberg equilibrium were verifi ed with the chi-square test. Analysis of litter size traits was performed using the General Linear Model, which included the potential environmental effects. Additive and dominant allele variances were observed by the regression procedure. In the studied population of sows, the frequency of heterozygotes (0.5149) for PRLR gene exceeded the total number of AA (0.0198) and BB (0.4653) homozygotes, which resulted in a high proportion of B allele (0.7228). The results for PRLR showed statistically signifi cant (P<0.05) differences in fi rst parity sows between BB and AB genotypes for TNB and NBA. Signifi cant differences (P<0.05) were recorded in third parity sows between BB and AB genotypes for NBA, and in AA genotype versus AB and BB genotypes for NMUM. The fourth and subsequent parity sows of AA genotype had a signifi cantly higher (P<0.05) rate of NBA as compared with those of AB and BB genotypes. In all parities analysed, the difference between the BB and AB genotypes for NBA was statistically signifi cant (P<0.05). Interpretation of the results at the levels of phenotypes and either additive or dominant variance was quite diffi cult due to the small number of AA homozygous sows. The calculation model yielded a signifi cant effect (P<0.05) as well as tendency (P<0.1) for the mentioned effects except for age at fi rst farrowing.

Comparative study of two, for the marketing most important, egg quality parameters (egg weight and egg shell strength) in two genotypes of commercial laying hens was realized. Egg production, egg weight (size) and egg shell strength in ISA Brown (14,879) and DeKalb White (15,376) layers, housed in battery cages under similar in-house environment and feed complete mixtures according the technological nutrient recommendation, were followed through the laying cycle. Egg weight and egg shell strength were analyzed in the Laboratory for testing egg quality using Egg shell Gauge (Robotmation Co. Ltd., Tokyo, Japan), computerized equipment that perform unbiased, shell breaking strength values. Both genotypes have high egg production that was close to the technological level of laying. No differences in egg number/hen housed were noticed. DeKalb White layers produce on average 1 g bigger eggs than the ISA Brown line layers (64.18 g vs 63.17 g), resulting in better feed to egg mass conversion. ISA Brown layers produce eggs with stronger egg shell (3864.52 g/cm 2 ) compared to DeKalb White genotype (3575.78 g/cm 2 ). High summer temperature influence the strength of the egg shell in both genotypes, resulting in lower strength compared to average egg shell strength values.

The aim of the present study was to investigate whether and to what extent the RNF4-SacII gene polymorphism influences reproduction performances in hyperprolific sow lines. The study involved 101 Landrace x Large White crossbred sows, with 461 records collected on the following reproductive traits: Total Number of piglets Born per litter (TNB), Number of piglets Born Alive per litter (NBA), Number of StillBorn piglets per litter (NSB), piglet Pre-Weaning Mortality (PWM) and Number of piglets at Weaning per litter (NW). The least square method with the GLM procedure in SAS with eight effects was used to pursue the data analysis. Study results revealed that TT homozygotes and TC heterozygotes had a significantly higher (p < .05) NW than CC homozygotes for the lifespan performance in all parities and first parity analysed. In the fourth parity analysed, TNB and NBA in TC genotype were significantly higher (p < .05) as compared with TT genotype. Based on the lifespan performance, significant effect (p < .05) was recorded for order of parity on TNB, NBA and NW, for farrowing season on TNB and NSB, and for lactation length on PWM. In the second parity, significant effect (p < .05) was recorded for sire of boar on NSB and for gestation length on TNB. Only in the fourth parity, significant effect (p < .05) of RNF4 gene was observed on NBA. There was significant additive effect (p < .05) of the RNF4 gene polymorphism identified on NW in all parities analysed, and significant additive and dominance effects (p < .05) on NSB in the third parity analysed. In conclusion, additional research on related production pig genotypes is necessary to elucidate the effect of RNF4 gene mutation on reproductive traits.

Eggs as a high valued nutrition product with acceptable price are required on the market, and therefore regular control of their quality is necessity. The aim of this trial was to monitor some quality parameters in eggs for consumption: egg (weight) mass and egg shell quality in M, L and XL weight classes produced by different producers, therefore confirming their marketing quality. From different markets in the region of Skopje, eggs from M, L and XL classes were purchased as different brands mostly present on the Macedonian market. Eggs were analyzed the same day. Egg quality was analyzed using computerized equipment for measuring egg shell strength (Eggshell Force Gauge) and automatic machine Egg Multi Tester EMT 5200 for measuring of the internal egg quality (Robotmation Co. Ltd., Tokyo, Japan). It was noticed that eggs in L and XL weight classes were mixed with eggs weighting less than the minimum weight for these classes, or more preciselly in L class eggs several pieces of M weight classs were notified and in XL weight class some percent of L class eggs were monitored. Only 20 sampless (26.66%) of M class eggs had sufficient value for egg shell strength, while in 110 analyzed samples of L class only 35 samples (30.43%) fulfill required egg shell strength. Eggs from analyzed brands in general do not fulfill required marketing quality in respect to the analyzed parameters: egg mass and egg shell strength of the eggs for consumption.