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An Analysis of Rotational Line Mating Using Computer Simulation
35-39Views:514In a simulation examination, we analyzed the effect of the family size and the rate of pairing on the survival of rare genes, to keep the level of variation of the genepool and to avoid the loss of alleles.
The population size was 360 animals. In the simulation, we calculated on the basis of a discrete population. We placed the 360 animals into different clusters, with 3 types of frequencies of alleles and 3 types of groups. We assumed 2, 3 or 4 alleles in 8 loci. We generated 15 generations using the same mating and selection system used in practise. The simulation was written with Scilab 2.7.2 software, and evaluated with SPSS software.
There were significant changes in the effect of family size on the genetic variation in the following cases: when the base population had the same gene frequencies in all loci, and when the gene frequencies were between 0.125-0.75. In these cases, we found that the smaller families (10 animals/cluster) were better than the larger families (30 or 90 animals/cluster). The first generation where there accured a loss of alleles was averagely earliest in larger families (90 animal/cluster). This average was 3.37 generations. When we are searched the effects of the different rates of pairing we found those cases most favourable when the ratio of males and females was 1:2 or 1:4 as compared to 1:9. The first generation where there was a loss of alleles was averagely earliest at the ratio of pairing male and females of 1:9 (the mean was 3.05 generations) when the frequency of the rarest allele was 0.0069.
The recently introduced rotating-random mating system is an eligible method for small populations for the preservation of genes. -
Coagulase-negative staphylococci in ewe udder surface and raw milk samples
221-225Views:603Coagulase-negative staphylococci (CNS) are among the major causes of subclinical mastitis in dairy ewe flocks. This has a financially significant impact on the ewe dairy sector and consumer health. The determination of the bacterial count, particularly CNS, is critical in terms of the quantity and quality of ovine milk. Thus, the purpose of this study was to quantify the CNS count in the udder surface and raw milk samples of the ewe, in addition to identifying CNS strains (n=8) collected from udder surface and individual raw milk samples by 16S rRNA gene sequencing. A total of 164 samples of udder surface and raw milk originated from four sheep farms were tested. The obtained values were compared between the different farms. Furthermore, values during 2018 and 2019 in the case of Farm I were compared. Significantly higher (p<0.05) average count was observed in udder surface samples taken from Farm I (2.8±1.0 lg CFU/cm2) than that of Farm III samples (2.3±0.6 lg CFU/cm2). In the case of individual raw milk, the higher value was observed in samples derived from Farm III (3.5±0.9 lg CFU/mL), while the obtained value was significantly lower (p<0.05) in samples originated from Farm IV (1.8±0.4 lg CFU/mL). In the bulk tank milk samples, the highest mean value was 5.3±0.4 CFU/mL, and there was no significant (p>0.05) variation between farms. Coagulase-negative staphylococci counts were decreased to a certain extent in both sample types tested during 2019 except for individual raw milk derived from the Tsigai breed. The correlation between the mean CNS counts of udder surface and individual raw milk was very weak (r=0.048). Staphylococcus simulans, Staphylococcus auricularis, and Staphylococcus equorum were identified by molecular sequencing and Staphylococcus simulans were the most frequently identified CNS species. A higher CNS count of bulk tank milk than individual raw milk indicates possible contamination during milking and storage. Therefore, further studies are required to investigate the other sources of bulk tank milk contamination to improve the hygienic quality of milk.
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Lambing Frequency in the Ile de France, Suffolk and Babolna TETRA Stocks of Babolna c.o., Szendrő
29-32Views:822Lambing frequency of three different genotypes was evaluated in the breeding stock of Babolna c.o. Szendrő. Ile de France, Suffolk and Babolna TETRA breeding ewes gave the data for the further evaluation. The main aim of this research was to find out if there is any significant effect of selected parameters (registration class, lambing season, lambing type and the years) on the lambing frequency, the period between consecutive lambings. Production parameters of 9,471 Ile de France, 1,244 Suffolk and 7,618 Babolna TETRA ewes were collected and processed. The analysis covered the period between the years 1989-1999. It was concluded that not all of the evaluated parameters had a significant effect on lambing frequency. Not all of the genotypes showed significant differences, according to the examined parameters.
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Evaluation of Hungarian Sporthorse mare performance tests
83-87Views:558Results of the Hungarian Sporthorse mare performance tests were evaluated. Data from the period of 1993-2009 were used, covering
scores of 618 3-year-old and 310 4-year-old mares, 109 of them were tested at both ages. Seventeen traits were scored on the tests, which
covered ten conformational, three free jumping performance and four movement analyses traits, respectively. Breeding value estimation was
based on BLUP animal model. Test year, age and owner were included in the model as fixed effects. Variance components were estimated
with VCE-6 software package. Heritabilities ranged from 0.32 (frame) to 0.50 (saddle region) for conformation traits, from 0.39 (jumping
style) to 0.49 (jumping ability and jumping skill) for free jumping traits and from 0.20 (walk) to 0.48 (canter) for movement analysis traits.
Breeding value indexes were constructed for each trait group. Conformation index was computed based on the weighted scores of the
breeding values of conformational traits. The conformational score scales were used as weightings. Free jumping and movement indexes
contain the proper breeding values with equal weights. A total index was also constructed using conformation index, two times the free
jumping index and two times the movement index. Each breeding values and breeding value indexes were presented with the mean 100 and
standard deviation of 20 for the easier understanding. -
Correlation between body condition change and reproduction parameters of Holstein-Frisian cows after calving
49-52Views:430The authors examined the body condition with relation to reproduction of Holstein-Friesian cows on three dairy farms in the South Plain region. During the examination they analyzed the data of 516 births of 494 Holstein-Friesian cows. They were trying to find correlation between the first service, the service period and the service rates. The examinations with regard to the correlations were different from the ones published in the professional literature. The body condition at the time of calving affected the interval from calving to the first service but not the conception
rates or the service period. The examinations did not prove any correlations between body condition changes and reproduction.