[The genetic contribution of cows to the prevalence of mastitis in the following generation]. / Genetický podíl krav na prevalenci mastitid v následující generaci.

Investigations of mastitis prevalence were performed in 1227 dam-daughter pairs during 1985-1988. From the records of the last 10 years, the findings concerning mammary gland were obtained. Six herds of agricultural co-operatives in the Brno region were investigated. In the early period the Bohemian Pied breed, later the crosses of this breed with Red Holstein and a low genetic proportion of Ayrshire cattle, dominated in the set of cows. Udder health was assessed using the clinical and bacteriological findings in individual udder quarters and the results of the rapid mastitis test NK. Based on this data, the cows were divided into two groups--resistant and susceptible. The lactation order in which the disease appeared for the first time was of great importance. The occurrence of the disease in daughters and udder health in dams were in a significant relation (P less than or equal to 0.01). While nearly 50% of daughters of susceptible dams were affected, it was only 25% in daughters of the resistant group. The assessment of heritability of resistance to mastitis was carried out on the principle of dam-daughter regression. The index of heritability h2 = 0.52 +/- 0.06 was calculated. The results show that the genetic contribution of dams to the susceptibility of daughters to mastitis is significant.

[Similarity in the incidence of mastitis in the daughters of related bulls]. / Podobnost prevalence mastitid u dcer príbuzných býku.

The overall prevalence of mastitis in the cow population, selected with respect to sire relatedness, was 12%. As positive for mastitis the cows with positive bacteriological findings in milk were considered. In order to objectify the evaluation by regarding the lactation number achieved, the index of morbidity In was introduced (In = number of positive findings/lactation achieved). Using this index, the groups of halfsisters--daughters of bulls and their sons--were compared and within-group variances were calculated. Differences in In between the groups of unrelated bulls were highly significant (P less than 0.01). In the progeny of sons of the same bull no significant differences were found. This indicates the role of genotype in the susceptibility to mastitis. Mean In value was 0.04 and 0.05 for the progeny of Czech Pied and Friesian breed, resp. No marked differences were observed between the groups of daughters of related bulls. The portion of Staphylococcus infections in the total number of positive findings was higher in the progeny of Friesian bulls (26.3 and 19.8% for the first and the second generation, resp.) than in the progeny of Czech Pied bulls (16.2 and 16.5% for the first and the second generation, resp.).

[Incidence of mastitis in cows of various breeds and their crosses-- estimation of the heredity of this disease]. / Výskyt mastitid u krav ruzných plemen a jejich krízencu--odhad dedivosti k tomuto onemocnení.

In a large set of cows (24,165 head), consisting prevailingly of Bohemian Pied breed, Black Pied Lowland and Holstein breeds, and of their crosses, significant differences in the incidence of mastitis were proved. Mastitis was demonstrated by the bacteriological findings in milk. The lowest mean incidence was recorded in the cows of the acclimatized Bohemian Pied breed (8.0%). As observed in the examined population, the increasing genetic proportion of solely dairy breeds results in higher demands on the environment, and the susceptibility of animals to mastitis usually increases. In three-breed crosses of this set, mastitis was found in 699 animals, i. e. in 25.4%. With respect to mastitis prevalence, a heritability estimate was performed on the basis of the first and second lactation using the method of alternative characters. In the Bohemian Pied breed, the heritability estimate was h2 = 0.17 +/- +/- 0.08, in the Black Pied Lowland breed h2 = 0.28 +/- 0.14.

[Differences in susceptibility of cows, in half-sisters by the same sire to mastitis]. / Rozdíly ve vnímavosti krav, polosester po otcích, k onemocnení mlécné zlázy.

The set of 9,555 cows, Bohemian Spotted breed, was studied if the sires contributed significantly to higher resistance, or on the contrary to susceptibility, of daughters to mastitis. The study was performed in 67 groups of half-sisters. Statistically highly significant (P less than 0.01) and significant (P less than 0.05) differences were proved as regards the frequency of bacteriologically positive and negative half-sisters in 36 groups as compared with the frequency ratio of positive and negative animals in the population. The daughters of 20 sires were more influenced in the positive sense, i. e. they suffered from mastitis less frequently than the daughters of 16 sires with a higher occurrence of the disease.

[Heredity of the position of rudimentary teats in cows of the Czech Spotted breed]. / Dedicnost lokalizace nadpocetných struku u krav plemene ceské strakaté.

A characteristic effect of bulls on the distribution of rudimentary teats in their daughters was demonstrated by the study of the influence of the genotype on the location of extra teats. The comparison of the mother--daughter pairs showed that the concordance of location of a single teat either on the right or on the left between the mother and daughter was found in 86.40% of all cases, whereas discordance was found just in 13.60% of the examined pairs. Concordance in the distance of rudimentary teats in a caudal direction from the rear teat was observed in 61.00% of the cases and discordance in 39.00% of the pairs. In 16 pairs of dizygotic twins, a congruence was also found in the majority of cases between the sibs as well as between the heifers and their mothers. In the whole set of cows under study, rudimentary teats located caudally represented 87.88% of all extra teats, small teats between the normal fore and rear teats represented 2.74%, rudimentary teats at the rear teats 9.03% and those at the fore teats 0.35%.

Effect of DDT and gamma-HCH on the biological properties of staphylococci.

The effect of DDT and gamma-HCH in concentrations of 100, 50, and 10 micrograms on the biological properties of staphylococci was studied. Both substances proved to be inhibitory to coagulation of rabbit plasma and to penicillinase production, causing depigmentation of the colonies. The morphological structure of cells is affected by these substances as well. The growth of the strain is not substantially influenced. Gas chromatography proved that staphylococci do not participate in the DDT and gamma-HCH degradation in the medium.

[Serum testosterone levels and response to administration of chorionic gonadotropins in bovine hermaphrodites]. / Hladiny testosteronu v krvi a odezva na aplikaci choriového gonadotropinu u bovinních intersexu.

The concentration of testosterone in the blood and its response to administration of chorionic gonadotropin was examined in two bovine intersexes (testicular pseudo-hermaphroditism) and two control bulls without disorders in sexual differentiation. The levels of testosterone in the blood were markedly lower in both intersexes than in the control bulls. Both intersexes, unlike the control bulls, also showed a response of the blood testosterone level to the administration of chorionic gonadotropin. The conclusion is that in the given type of intersexuality the incretion function of the testes is mardedly deficient as to androgen production and functional hormonal reserve.