Milan Maletić

Efficiency evaluation of a bivalent vaccine in the prophylaxis of mastitis in cows.

Mastitis in cows represents one of the most actual problems in intensive dairy production. The longtime different approaches to the treatment of mastitis have not offered a suitable solution, and the problem of mastitis is still present and acute. Prevention of pathogen penetration into the mammary gland, its colonization and multiplication impose a constant need for regular inspections of milk, as well as preventive and therapeutic measures to reduce the incidence of mastitis. Studies in the field of vaccination of ruminants against mastitis pathogens suggest a limited success in obtaining significant results in immunoprophylaxis. Considering the results of other researchers and our own research, and bearing in mind the problems mastitis caused by Staphylococcus aureus and Streptococcus agalactiae represent, the aim of this study was the preparation and testing of an indigenous vaccine prepared with two stable strains, SAU 7 (S. aureus) and SAG 3 (Str.agalactiae). The dose was 5 mL/cow and consisted of inactivated bacterial S. aureus SAU 7 cells in a concentration of 1x1010 cfu/mL and Str. agalactiae SAG 3 in a concentration of 4 x 109 cfu/mL. The number of somatic cells in the milk samples during the whole study period was higher in vaccinated cows in both groups compared with the control, but this difference was not statistically significant. The concentration of immunoglobulin IgG in the milk of vaccinated cows was significantly higher than the concentration of this class of proteins in the milk of unvaccinated cows. [Projekat Ministarstva nauke Republike Srbije, br. III 46002]

Analysis of reproductive parameters after intrauterine insemination of sows with semen stored for different time periods

Introduction. Artificial insemination of sows with cooled semen has become a routine practice in the swine industry and has almost completely ruled out natural mating. The storage time of the cooled semen and preservation of its qualitative parameters are of the upmost importance and depend partly on the semen extender used. The aim of this study was to determine the quality of cooled semen during storage in a thermobox with a commercial extender by assessment of sperm motility, cytomorphology, and assessment of reproductive parameters in sows after intrauterine insemination. Materials and Methods. The semen was preserved with Duragen® (Magapor, Spain) extender and stored at 17±1°C. A total of 110 sows were included in the study and randomly divided into four groups: K1 (n=25) , K2 (n=25), K3 (n=30), and K4 (n=30). The sows were inseminated twice with semen (>1x107/ml spermatozoa) which had been stored for 1 day (S1), 3 days (S3), 5 days (S5), or 7 days (S7). Pregnancy was diagnosed by imaging ultrasound.Results and Conclusions. The best results were obtained when the sows were inseminated with semen stored for one day. However, there were no statistically significant differences in the number and vitality of newborn piglets when semen stored for 3 or 5 days was used. Intrauterine insemination resulted in a satisfactory number of farrowings and piglets despite the fact that a relatively low number of spermatozoa was determined in each dose used. The use of semen with a higher dilution rate and its intrauterine application ensured a larger number of obtained doses from one ejaculate and indicates this would lead to a more profitable use of boars.

Istraživanje polimorfizma gena za κ-kazein i beta-laktoglobulin u buše i holštajnfrizijske pasmine mliječnih krava u Srbiji

The aim of this study was to determine the distribution of κ-casein (κ-CN) and β-lactoglobulin (β-Lg) genotypes in the autochtonous (Busha) and dairy (Holstein-Friesian, HF) cattle breeds with PCR-RFLP (polymerase chain reaction restriction fragment length polymorphism). For the amplification of κ-CN and β-Lg gene fragments specific primers were used. After digestion with specific endonucleases genotypes were determined for both genes in 18 Busha and 19 HF cows. The results showed that κ-CN gene was represented with the AA genotype in 31.58 % HF cows, AB in 52.63 % cows, whilst the genotype BB was found in 15.79 % cows only. Among the examined Busha cattle 44.44 % cows had AA genotype and 55.56 % genotype AB for κ-CN. As for β-Lg gene in HF breed, AA genotype was found in 26.31 % cows, AB in 63.16 % and BB in 10.53 % cows. In Busha cows the following genotypes were established for β-Lg gene: AA in 44.44 % cows and AB in 55.56 %, whilst BB genotype was not found. These results indicate that Busha cows had a higher presence of A allelic forms of both genes (k-CN and β-lactoglobulin) than HF cows.