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Bombyx mori. L. (CSR2XCSR4) is a bivolitne crossbreed that produces high quantity of silk. The weights of worms and glands are directly related to the yield of silk, higher larval weights leads to higher silk production. In the present study, quantitative parameters of 5th instar and pupal stages of silkworm larvae were observed. The analysis of quantitative estimation showed that the maximum weights and lengths of silk gland and silk worm were recorded on 7th day of 5th instar larval stage. The day dependent variation in protein concentration was observed in total silk gland 5th instar larval and pupal stages.
Calving course of 100 cows of Limousine breed covered by bulls of the same breed as well as 100 cows of Polish Holstein-Friesian breed inseminated with Limousine bull's semen was investigated. In purebred population the material was taken from the beef cattle recording scheme provided by the Polish Association of Beef Cattle Breeders and Producers. In case of commercial crossing the material was taken from the questionnaires collected by the technicians representing Mazovian Centre of Animal Breeding and Reproduction in Łowicz. The data base covered calving course degree and calf body weight at birth degree. It was proved, that the significantly higher ratio of deliveries when human help was needed was stated in the purebred Limousine population (14%), in comparison to crossbreeding where the above mentioned ratio was only 7%. The most difficult calvings were observed for the calves of the highest birth weight. The high ratio of assisted calvings in commercial crossing as well as in purebred population of Limousines suggest that all of the deliveries should be monitored by the breeders. It should be also stated that the ratio of difficult calvings in the commercial crossing is significantly lower than that observed in purebred PHF population. Because of so low ratio of assisted calvings in commercial crossing with Limousine bulls it should be recommended to use the semen of bulls which pedigree show high body weight at birth and muscularity.
The aim of this study was evaluation of the quality of ejaculates of boars from Duroc and Pietrain breeds, and also crossbreeds born in different seasons. Materials used for the study were gathered during the process of breeding boars. There were 143 boars of breeds Duroc, Pietrain and their crossbreeds (Duroc x Pietrain and Pietrain x Duroc). The 20 442 of boars’ ejaculates were examined between 1997–2009 in the Małopolska Biotechnology Centre – Examinations Station of Boars in Czermin. Ejaculates were evaluated basing on: the volume of spermatozoid fractions, the percentage of progressive spermatozoids, spermatozoid concentration, total count of progressive spermatozoids and the total number of insemination doses obtained from one ejaculation. The parameters of examined ejaculates of boars races were analyzed statistically accordingly with their births seasons: spring (from 22nd March to 21st June), summer (from 22nd June to 21st of September), autumn (from 22nd September to 21st of December), winter (from 22nd December to 21st of March). The studies have shown the significance of impact that season of birth has on semen quality of boars and crossbreeds of evaluated races. The highest reproductive potential expressed as a number of insemination doses, was found in boars of Duroc and Pietrain breeds born in the summer. In case of crossbreeds, the best quality of sperm was found in males born in the winter season.
Association of CAST and RYR1 genes polymorphism with carcass and meat quality in crossbreed pigs with a share of Pietrain breed. The aim of this study was to determine the effect of the calpastatin (CAST/TaqI) and ryanodine receptor (RYR1) genes polymorphism on carcass and meat quality traits in Pietrain crossbred pigs. The polymorphism in CAST and RYR1 genes was detected using the PCR-RFLP (Restriction Fragment Length Polymorphism Analysis of PCR-Amplified Fragments) method. Two alleles of CAST gene were identified–A(0.34) and B (0.66) and three genotypes–AA(0.21), AB (0.25) and BB (0.54). In relation to carcass and pork quality, no statistically significant differences were found between the CT and CC genotypes of RYR1 gene as well as between AA, AB and BB genotypes of CASTgene. In addition, no significant interaction was found between CAST/TaqI × RYR1 genotypes and all the analyzed carcass and meat quality traits.
Comparison of calving course of Charolaise purebreds and their crossbreeds with Polish Holstein-Frisian cows. Calving course of cows of Charolaise breed covered by bulls of the same breed as well as cows of Polish Holstein Friesian breed inseminated with Charolaise bull’s semen was investigated. In purebred population the material was taken from the beef cattle recording scheme provided by the Polish Association of Beef Cattle Breeders and Producers. In case of commercial crossing the material was taken from the questionnaires collected by the technicians representing Mazovian Centre of Animal Breeding and Reproduction in Łowicz. The data base covered calving course degree and calf body weight at birth degree. It was proved, that the significantly higher ratio of deliveries when human help was needed was stated in the purebred Charolaise population (24.5%), in comparison to crossbreeding where the above mentioned ratio was only 12.2%. The most difficult calvings were observed for the calves of the highest birth weight. The high ratio of assisted calvings in commercial crossing as well as in purebred population of Charolaises suggest that all of the deliveries should be monitored by the breeders. It should be also stated that the ratio of difficult calvings in the commercial crossing is significantly lower than that observed in purebred PHF population. Because of so low ratio of assisted calvings in commercial crossing with Charolaise bulls it should be recommended to use the semen of bulls which pedigree show high body weight at birth and muscularity.
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