Peter Juhás

THE RELATIONSHIP BETWEEN THE LENGTH OF PRODUCTIVE LIFE AND THE BODY CONFORMATION TRAITS IN COWS

The aim of this study was to analyze the length of productive life in 118 646 dairy cows of the Slovak Simmental breed. The average length of productive life reached 1451 days (3.98 years). The recorded factors with most important impact to the length of productive life were: milk production at first lactation (F = 7736.88+++), year of culling (F = 4890.54) and the age at first calving (F = 2759.81). The length of productive life was significantly affected by reason of culling (F = 272.43) and the Sire (F = 53.43). The analysis of effects of exterior traits to the length of productive life was done in group of 6585 culled cows. From the main exterior traits the most important impact was recorded for body frame (F = 17.39+++), udder (F = 9.43+++) and feet and legs (F = 6.41+++). For more detail advisement was tested the influence of partial exterior traits. From the partial exterior traits the most significant effect to length of productive live had udder depth (F = 26.04+++), teats length (F = 18.49+++), teats thickness (F = 3.23+++) and teats placement (F = 3.31++). From partial traits of feet and legs the most significant effect to length of productive live had heel joint expression (F = 9.10+++) and foot (F = 5.47+++). Results from the present study confirmed the important influence of main and partial exterior type traits of Slovak Simmental breed on the productive life of cows.

The effect of added organic selenium on nutritional value, chemical and technological quality characteristics of pork

The aim of the research was to evaluate the effect of organic selenium in the feed on the selenium content in pork and selected qualitative traits of pork. The experiment was performed on 29 pigs in the control group and 21 pigs in the experimental group. Animals in both group were fed by same mixture, feed mixture for experimental group was supplemented by 300 µg selenium per 1 kg mixture. Selenium was in form protein-mineral premix. Selenised feed mixture increased the selenium concentration in muscles, selenium content in muscle was significantly higher in experimental group (P < 0.01). There was not difference between groups in chemical composition of muscle – water, proteins and intramuscular fat content. Statistically significant difference was found only in saturated fatty acids ratio (P < 0.05), other fatty acids did not differ between groups. No statistical difference was found in pH, drip loss and shear force. The pork with higher content of selenium showed significantly lower oxidative activity (P < 0.01) and higher color stability (P < 0.01).

THE INFLUENCE OF HEALTH STATUS IN CALVES WITH SUBSEQUENT GROWTH OF HEIFERS AND MILK PRODUCTION IN DAIRY COWS

The aim of this study was to analyze the association between enteritis and pneumonia during first months of life and subsequent growth and milk production traits of these animals. A total of 1327 calves were followed in this study. Calves were divided into three groups: Group A) healthy calves; Group B) calves that suffered from the enteritis one or more times from the birth to 6 th month of age; and Group C) calves that suffered from birth to 6 th month of age from the pneumonia. Subsequently all animals were observed at the following age stages: calves, heifers and cows. For all groups (age stages) the body weight and daily weight gain in calves (in the breeding period from birth to 6 th month of age), the weight and daily weight gain weight in heifers (in the breeding period from 7 th to 25 th month of age) and production parameters of cows in the first lactation (milk in kg, fat in kg and protein in kg) was recorded. Calves in Groups B and C exhibited lower average daily gain (690.40 g, SD = 186.18, N.S. and 636.80 g, SD = 221.19, P < 0.05 respectively) than healthy calves (Group A, 703.91 g, SD = 223.48). Heifers in Group B exhibited increased the daily weight gain (830.01, SD = 73.57, N.S.) compared to healthy animals (Group A, 828.31, SD = 89.16). The general hypothesis regarding the negative effect of the enteritis (in breeding age animals that suffer from disease) on growth in the Simmental breed has not been confirmed. Heifers that had suffered with the pneumonia (Group C) showed significantly lower average daily gain (784.64, SD = 102.96, P < 0.05) than heifers in group A and B. In the evaluation of milk production in the first lactation, average production of 5800 kg per lactation (SD = 3.96) was recorded in Group A cows. Cows in Group B in the first lactation produced the 5977 kg of milk per lactation on average (SD = 4.31). Cows from Group C in first lactation produced lowest amount of milk during the first lactation period (5674 kg, SD = 3.87), but difference among A, B and C group was not significant.