[Effect of bovine hypodermosis on various health indicators of milk in first-calvers]. / Vliv hypodermatózy skotu na vybrané zdravotni ukazatele mléka u prvotelek.

The effect of the last developmental phase of the warble fly (Hypoderma bovis de Greer) larvas was studied as exerted on some health indices of milk in 20 experimental (treated) and 18 control (untreated) first-calvers of the Pinzgau breed at two localities of an area affected by bovine hypodermosis in the period from May to June, 1975. The preparation Hypocid, at a dose of 15 ml per 100 kg of body weight, was applied externally in the lumbosacral region to the experimental animals in November, 1974. Throughout the experimental period (61 days) the milk was repeatedly examined bacteriologically and cytologically, the content of chlorides and the milk electric conductivity were determined. In none of the followed health indices of milk were significant differences in the values obtained from experimental and control first-calvers proved statistically.

[Effect of hypodermyiasis in cattle on milk-production indicators in 1st-calvers]. / Vliv hypodermatózy skotu na produkcní ukazatele mléka u prvotelek.

We investigated the effect of hypodermosis on the quantitative and some qualitative indicators of milk from 20 experimental and 18 control first-calvers of the Pinzgau cattle breed. The experiment took place at two experimental localities in mountainous pastures of the Central-Slovakian region. In the experimental animals, treated with Hypocid, the production of milk per dairy cow increased on an average by 115.98 kg, i.e. 24.83%, over the experimental period of 61 days (May, June) with an average invasion intensity of 5.94 larvas in control animals. Milk fat production increased on an average by 7.20 kg, i.e. 34.97%. Production recalculated to FCM milk amounted on an average to 31.61%. The profitability of treating hypodermosis with the Hypocid preparation is expressed by the average savings of 0.40 Kcs per litre of milk per day.

[Milking without additional hand stripping and health status of the mammary gland]. / Vynecháni rucního dodojování a zdravotní stav mlécné zlázy

A field trial was performed in two half-sib first-calver groups of the Bohemiam Spotted breed. Each group included thirteen animals, studied for the effect of milking without additional hand stripping on the health condition of the mammary gland for a period of one lactation. The indices of an udder health condition were not affected at an appreciable level of statistical significance (the clinical and bacteriological picture, the positivity of the Mastitis test - NK, the content of milk cellular elements, milk chloride ion content, lactose content, and the value of the chlorine-sugar number. The unstripped udder halves showed a slight increase of the irritation index (by 0.1), milk cellular element content (by 33 000 per per 1 ml), chloride ion content (by 0.81 mmol 1+-1), and chlorine-sugar number (by 0.03). However, the mentioned increase did not exceed the limits of the physiological ranges of the parameters under study - hence it cannot be treated as a sign of udder alteration due to milking without additional hand stripping.

[Influence of some factors on the electric conductivity of mixed milk]. / Vliv nekterých faktorú na elektrickou vodivost smesného miléka

The authors evaluated the method of the determination of the electric conductivity of purchased milk for the estimation of the hygienic aspects of mlik quality and for mass diagnosis of the inflammatory diseases of dairy cow mammary glands. The variability coefficient of duplicates varied from 1.37 to 3.09%. The study of the dependence of milk conductivity measurement on milk temperature revealed a statistically highly significant positive correlation between the values of these two factors. In the temperature range from 30 degrees C to 35 degrees C the coefficients of correlation ranged from 0.951 to 0.996. Furthermore, interference caused by milk acidity was examined during a five-day incubation of samples at 25 degrees C. A statistically significant difference was observed from the third hour of incubation (P less than 0.05) and a statistically highly significant difference from the fourth hour of incubation (P less than 0.01). the evaluation of the diagnostic value of the method of the measurement of electric conductivity in purchased milk revealed a positive correlation to the content of chloride ions (r = 0.69) and to the number of the cellular elements of milk (r = 0.33).

[Effect of various factors on the electric conductivity of mixed milk]. / Vliv nekterých faktoru na elektrickou vodivost smesného mléka

The authors evaluated the method of the determination of the electric conductivity of purchased milk for the estimation of the hygienic aspects of milk quality and for mass diagnosis of the inflammatory diseases of dairy cow mammary glands. The variability coefficient of duplicates varied from 1.37 to 3.09%. The study of the dependence of milk conductivity measurement on milk temperature revealed a statistically highly significant positive correlation between the values of these two factors. In the temperature range from 30 degrees C to 35 degrees C the coefficients of correlation ranged from 0.951 to 0.996. Furthermore, interference caused by milk acidity was examined during a five-day incubation of samples at 25 degrees C. A statistically significant difference was observed from the third hour of incubation (P less than 0.05) and a statistically highly significant difference from the fourth hour of incubation (P less than 0.01). The evaluation of the diagnostic value of the method of the measurement of electric conductivity in purchased milk revealed a positive correlation to the content of chloride ions (r = 0.69) and to the number of the cellular elements of milk (r = 0.33).