The aim of this study was to explain the birth season effect on Hereford bulls fattening results. The research was made within the project 'Baltic Grassland Beef' framework in years 2015 and 2016. Data about 41 Herford purebred bull was used in the research, grown in different farms of Latvia. Bulls were slaughtered in certified slaughterhouse 'Agaras' (Lithuania). The average birth weight of the Hereford breed bulls was in border from 42.9 -45.0 kg. The lowest birth weight was on spring season born bulls -42.9 kg, but the highest on winter season born bulls -45.0. Average realization age of bull's, in the research groups, was on range from 567 days to 661 days. Bulls born on autumn and winter before slaughtering were significantly older, respectively 661 and 655 days with live weight of 519.9 kg un 542.1 kg. On spring born bulls with age 600 days reached the biggest live weight -542.0 kg, respectively these group bulls average daily weight gain from birth to slaughter per day was the biggest among all the groups -831.9 g. The highest slaughter weight showed on autumn and winter seasons born bulls, respectively 275.5 kg and 274.8 kg. In the research groups on different seasons born bulls conformation score was from points 2.4 to 2.6. All the bull's carcass in the research groups were evaluated as 2nd and 3rd fat class. between the age before slaughter and average daily weight gain from birth to slaughter there is an important negative correlation (from r = -0.858 to = -0.977, p<0.05), except on spring season born bulls.

Aim. The aim of the study was to explain the difference of pH values in heifer and bull meat and to carry out an analysis of the effect of age in groups of both sexes. Methods. The study contains data on 2,469 beef breed and their crossbreed cattle fattened on farms in Latvia and Lithuania, slaughtered in a certifi ed Lithuanian slaughterhouse ʻAgaras’ in 2018. For the assessment of the effect of sex, the beef cattle were divided into 2 study groups: 1,266 bulls and 1,203 heifers. 3 study groups were created for analysis of the effect of age: 12 – 17 months; 18 – 23 months; 24 and more months. Analysis of the data acquired was based on the indicators of descriptive statistics. T–test and Pearson correlation analysis were used. Results. The average pH in the meat of bulls was 5.87 ± 0.011, but in the meat obtained from heifers – 5.66 ± 0.005 (p ≤ 0.05). Within the desired pH value from 5.4 to 5.8, the group of bulls comprised 65 % of carcasses and the group of heifers – 86 % of carcasses. In the group of bulls, 35 % of carcasses had an increased pH in the meat (pH –≥ 5.9), while in the heifers’group – 13%. For a small part of the carcasses in both study groups, too low pH was found in meat (pH ≤ 5.3), with 1% in the group of bulls and 0.4% in the group of heifers. An analysis of the effect of age found no signifi cant differences in pH values between bulls of different ages. In the heifers’study group, the highest pH in meat was found in the group above 24 months of age, pH–5.69. Correlation analysis between the meat pH and the slaughter results showed a weak or non–existent relationship. In the overall study group, stronger correlation was observed between pH and fat score (r = –0.21, p < 0.05). Conclusions. The results indicate that meat from heifers is better quality in terms of desired pH. Meat with the desired pH can be used in the production of high-quality products that provide higher profi ts.

Cattle fattening, first of all, should be beneficial for a farmer, therefore, in Latvia more suitable are such average intense fattening methods as fattening with grass fodder. In the world, demand for beef, produced in an environmentally friendly manner, ensuring the appropriate animal welfare conditions, is growing. The aim of the study was to find out the fattening results of Hereford (HE) and Aberdinanguss (AB) pure-bred bulls and their crosses when fed with grass fodder. The study was conducted in 2015 and 2016 within the framework of the project 'Baltic Grassland Beef'. AB crossbreed bulls were slaughtered when they were 519 ± 16.6 days old, but HE pure-bred bulls -584 ± 7.3 days old (p ≤ 0.05). The biggest live weight and slaughter weight showed HE crossbreed group bulls -557 ± 19.4 kg and 293 ± 12.2 kg, respectively, but the biggest live weight daily gain from birth to slaughter was observed to AB pure-bred group bulls -952 ± 24.7. Carcass conformation score in muscle development was the highest for AB pure-bred group bulls. Their average conformation score was 3.2 ± 0.08 points. In terms of fat score development, carcass with the best quality was obtained from HE crossbreed group bulls, the resulting fat score -2.4 ± 0.10. The obtained results prove that pure-bred and crossbreed bulls used in this research are suitable for fattening with grass in the conditions of Latvia.

Beef production must combine the interests of both producers and consumers, taking into account the sustainable use of environmental resources. The aim of the study was to analyze and compare the slaughter results, meet chemical composition and pH value of three beef breeds – Aberdinangus (AA), Hereford (HF) and Limousin (LI) bulls. The bulls were fattened on Latvian and Lithuanian farms, mainly using grass forage. The breed and age of bulls before slaughter significantly affected all slaughter results, except for fat class. From the meat chemical composition traits, the bull breed and age before slaughter had a significant effect only on the protein content. LI bulls showed the highest carcass weight 301.1±6.8 kg (p<0.05), dressing percentage 58.2±1.1% (p<0.05) and conformation score 3.56±0.18 points. The best fattened carcasses were obtained from AA bulls - 2.43±0.20 points. Muscle samples of musculus longissimus (M. longissimus) bulls of LI breed showed higher content of moisture (72.0±1.0%), protein (23.0±0.2%), ash (1.1±0.0%) and cholesterol (56.7±6.6 mg 100 g−1). AA breed bulls showed higher total fat (6.6±1.2%) and iron content (13.1±0.6 mg). The highest pH was observed in the meat obtained from AA bulls – 6.0±0.1, LI and HF breed bulls showed pH 5.8±0.0 and 5.8±0.1 respectively. Correlation analysis showed a significant, strong positive correlation between cold carcass weight and dressing percentage for AA and LI bulls, r=0.90 and r=0.88, respectively. For LI breed bulls, a strong positive correlation was also found between the cold carcass weight and the conformation score (r=0.98, p<0.01).