Summary In mammals, between‐species correlation between mature size and maturing rate is high. The within‐species relationship is not so clear. An experiment with 167 mice of small RoC57BL/6 and large RoNMRI lines was set up, to study the influence of animal mature size on maturing rate. The body mass of animals was measured every 3 days, between the ages 12 and 120 days. Individual ages at half the adulthood and at adulthood were determined on the basis of logistic growth curves. Three linear statistical models based on an allometric equation were used to test between‐line, between‐sex‐line, and between‐family maturing rates. Growth rate and maturing rate are within the species significantly affected by mature size. At mature size, the smaller RoC57BL/6 mice were older than the larger RoNMRI mice. In the model with the significant effects line, sex and family included, the same allometric coefficient was positive. The model which includes an allometric equation within line and sex was no better fitting than the previous model. Not all the estimates of allometric coefficients were within expected ranges, but standard errors were relatively high. Because significant effects are partly of genetic origin and standard errors are high, the selection for higher maturing rate might be possible without changes in mature size. No method for determining degree of maturity during growth has been found so far, therefore the selection would be relatively slow, due to the extension of generation interval. Zusammenfassung Adulte Größe und Wachstumsrate von RoC57BL/6 und RoNMRI Mäusen In Säugern ist die korrelazion zwischen adulter Größe und Wachstumstrate hoch, aber innerartlich ist diese Beziehung nicht so klar. In einem Versuch mit 167 Mäusen der kleinen RoC57BL/6 und der großen RoNMRI Linien wurde der Einfluß adulter Größe auf Wachstumstrate untersucht. Körpermasse wurde zwischen Altern von 12 und 120 Tagen alle 3 Tage erhoben. Alter bei halber und voller adulter große wurde mittels logistischer Wachstumskurven geschätzt. Drei lineare statistische Modelle auf der Basis logistischer kurven wurden verwendet zur Schätzung von Wachstumsraten für Linien, Geschlects‐Linien Gruppen und von Familien. Wachstums und Reifungsraten innerhalb Arten werden signifikant von adulter Größe beeinflußt. Die Mäusen der kleineren Linie waren bei Erreichen des adulten Gewichtes älter als jene der größeren. In Modellen mit den signifikanten Wirkungen von Linien, Geschlecht und Familien war derselbe Allometriekoeffizient positiv, aber im Modell mit Linien‐ und Geschlechtsspezifischen Allometriegliechungen war die Anpassung nicht besser. Nicht alle Schätzwerte der Allometriekoeffizienten waren innerhalb des Erwartdsungbereiches, doch waren die Standardfehler hoch. Da die Einflußfaktoren zum Teil genetischen Ursprungs sind Standardfehler hoch, sollte Selektion auf Wachstumstrate ohne Änderung der adulten Größe möglich sein. Allerdings ist keine Methode zur Schätzung der Reife währen des Wachstums bekannt, sodaß solche Selektion aufgrund verlängerter G...

Phenotypic and genetic parameters were studied in Slovenian autochthonous sheep breed Jezersko-Solcavska. The data originate from Slovenian selection program. The number of sheep in Slovenia, especially of autochthonous breeds is increasing due to abandoning of intensive farming on many farms. Another reason are subsidies, favouring low intensity production and autochthonous breeds. The breed is fertile during the whole year. Estimated heritabilities are: 0.078 for birthweight, 0.401 for weight at 60 days and 0.390 for weight at the end of the test at average age of 185.35 days.

P.G. 600 ® is often used as an estrus promoter on sows with controversial results. This experiment was carried on a well managed farm with 2,500 sows during one calendar year. Half of primiparous sows, 502 of a total of 1005, were treated with P.G. 600 ® at weaning. Three week observation time formed one batch of data with an adequate number of observations for statistical evaluation. Every batch was evaluated separately. Moderate improvement of reproduction traits was found in the experimental group. Both, the percentage of sows in estrus after weaning (95.98 % versus 94.99 %) and the percentage of sows farrowing the second litter (90.34 % versus 88.38 %) was higher in the experimental than in the control group. Experimental group had a slightly larger litter (14.22 versus 13.85), shorter period to first estrus (6.16 days versus 7.10 days) and shorter period to successful insemination (8.10 days versus 8.56 days). Improvement of fertility traits was observed particularly in late winter, spring and early summer, but it was not confirmed by statistical evaluation. Unexplained variance in the statistical model was high. The use of P.G. 600 ® in well managed heards in Slovenian moderate climatic conditions is unnecessary. That conclusion cannot be generalised for other managements and climatic conditions.

The frequencies of alleles on PrP locus and its effect on growth of rams were studied in Jezersko solčavska and improved Jezersko solčavska breed. Genetic resistance against scrapie depends on genotype on PrP allele. Animals were housed in quarantine at age of approximately 120 days. They were moved to test station where stated with test at the age of 184 days. The procedure was finished at the age of 257 days. During the test the animals were genotypized on the PrP locus. The frequency of the most susceptible allele VRQ was only 3.11 % and of the most resistant allele ARR it was 18.56 %. Daily gains between ages of 120 and 257 days and between 184 and 257 days were not influenced by PrP genotype. The PrP genotype influenced only daily gain between birth and age of 257 days. ARR allele as heterozygote in combination with other alleles showed good growth performances. The ARR homozygotes grew slower in comparison with other genetic combinations, but the differences in comparison to the other genotypes were not significant with exception of live period daily gain.