FACTORS AFFECTING ACTUAL AND ADJUSTED 90-DAY, 205-DAY AND 365-DAY WEIGHT OF CHAROLAIS CALVES

Body weights on 90 ± 45 days and 205 ± 45 days are body weights used for selection in suckler herds, likewise body weight on 365 ± 45 days are used for selection in performance test according to the Slovenian rules for recording in animal production, which is based on the International Committee for Animal Recording - ICAR. Dilemma which body weights are more suitable: the actual, or the adjusted ones at the recommended age of calves is often present. Comparison between fixed effects on actual and on adjusted 90-day, 205-day and 365-day weights of Charolais calves have been studied. Calves (320) were born from 1995 to 2005 on Educational and Research Animal Husbandry Centre Logatec (Slovenia). Fixed effects of sex, parity, year of birth and birth weight were included in a model for the actual and adjusted body weights. Birth weight was included as linear regression. It has been concluded that parameters affected the actual body weights affected adjusted body weights, too. Birth weight and year of birth influenced 90-day, 205-day and 365-day weight. Parity influenced only 90-day weight, while sex influenced 205-day and 365-day weight. Coefficients of determination for adjusted 90-day weight (0.38), 205-day weight (0.38) and 365-day weight (0.73) were higher than for actual body weights (0.20, 0.30 and 0.60, respectively)

FACTORS AFFECTING ACTUAL AND ADJUSTED 90-DAY, 205-DAY AND 365-DAY WEIGHT OF CHAROLAIS CALVES

Body weights on 90 ± 45 days and 205 ± 45 days are body weights used for selection in suckler herds, likewise body weight on 365 ± 45 days are used for selection in performance test according to the Slovenian rules for recording in animal production, which is based on the International Committee for Animal Recording - ICAR. Dilemma which body weights are more suitable: the actual, or the adjusted ones at the recommended age of calves is often present. Comparison between fixed effects on actual and on adjusted 90-day, 205-day and 365-day weights of Charolais calves have been studied. Calves (320) were born from 1995 to 2005 on Educational and Research Animal Husbandry Centre Logatec (Slovenia). Fixed effects of sex, parity, year of birth and birth weight were included in a model for the actual and adjusted body weights. Birth weight was included as linear regression. It has been concluded that parameters affected the actual body weights affected adjusted body weights, too. Birth weight and year of birth influenced 90-day, 205-day and 365-day weight. Parity influenced only 90-day weight, while sex influenced 205-day and 365-day weight. Coefficients of determination for adjusted 90-day weight (0.38), 205-day weight (0.38) and 365-day weight (0.73) were higher than for actual body weights (0.20, 0.30 and 0.60, respectively)

FAT TISSUE DISTRIBUTION BETWEEN SUBCUTANEOUS AND INTERMUSCULAR FAT TISSUE IN SIMMENTAL AND BROWN BULLS

Simmental and Brown bulls from progeny testing station were used to evaluate the effect of breed on fat tissue partition between subcutaneous and intermuscular fat. Bulls (37 Brown and 34 Simmental breed) were slaughtered at the same degree of fatness. After slaughter carcasses were first cut into different carcass cuts and further on into lean meat, fat, bones and tendons. Fat was divided up into subcutaneous and intermuscular. Simmental bulls were heavier (average cold carcass side weight from Simmental bulls was 167 kg vs 147 kg from Brown bulls) at the same percentage of total carcass fat (10.5 %). Breed has no effect on percentage of subcutaneous and intermuscular fat tissue nor on percentage of subcutaneous fat from total carcass fat. Simmental bulls had higher (p<0.05) subcutaneous fat percentage (subcutaneous fat in the cut / total fat in the cut) in brisket and flank and lower (p<0.05) in shoulder than Brown bulls

RESULTS OF BEEF CARCASS GRADING IN SLOVENIA FROM 1997 TO 200

Carcass traits (carcass weight, conformation and fatness note and payment class) were collected in the commercial slaughterhouses with automatic data collection for the last ten years. On the average more than 80 % of all graded bovine animals in Slovenia were taken into the study. The average carcass weight of calves increased by 20 kg, but was with 79 kg still very low. The carcass weight of young bulls, heifers and cows varied among different years, but no trend could be noticed, whereas carcass weight of old bulls decreased markedly (more than 50 kg). The carcass conformation decreased in all categories, in calves, young bulls and heifers by two thirds and in old bulls and cows by more than 0.9 of conformation class. The carcass fatness decreased in all categories too. The most pronounced decrease was noticed in the category of old bulls (0.6 class) and the least in young bulls (0.2 class). Most of the above mentioned changes occurred after the year 2002 in the category of cows and after the year 2001 in all other categories. The main reasons for changes in conformation and fatness were probably the changes in cattle breed structure in Slovenia

THE EFFECT OF AGE AT THE BEGINNING OF GRAZING SEASON ON 205-DAY AND 365- DAY WEIGHT IN CHAROLAIS AND LIMOUSINE CALVES**

**Original scientific paper Abstract: The effect of age at the beginning of grazing season on 205-day and 365-day weight of calves was analysed. Data included 234 Charolais and 122 Limousine calves reared at the Educational and Research Animal Husbandry Centre Logatec (Slovenia). Calves were born between years 1995 and 2006. The effects of breed, sex (nested within breed), parity (nested within breed) and year of birth as fixed effects were included in the model. Age at the beginning of grazing season and birth weight as linear regression were also included in the model. Age at the beginning of grazing season as linear regression influenced 205-day weight (p=0.0007) and 365-day weight (p=0.0049), too. Breed, sex within breed, year of birth, and birth weight also influenced 205-day and 365-day weight. Coefficient of determination was higher (0.80) for 365-day weight compared to 205-day weight (0.51)