Object of work. 1. To review and compare the productivity qualities of the pig breeds bred in Vilnius zone (Lithuanian white, Yorkshyre, Landrace, and Pjetren); 2. To determine the impact of the age, sex, and breed on the pig muscularity. Conclusions. 1. The highest muscularity within the weight limit 95-100 kg makes 53.1 percent, and at the weight of 110-115 kg the muscularity amounts to only 47.5 per cent. While the weight of piglets is increasing, the amount of muscles decreases but the amount of fat increases. It was established that at every 5 kg the fat thickness increases by 1 mm. 2. The weight had the highest influence on the piglets of the Landrace and Pjetren breeds. Based on the research, it can be stated that while the weight increases from 90 kg to 110 kg, the fat layer of the Landrace piglets decreases from 16.1 mm to 14.4 mm, and the fat layer of the Pjetren piglets, on the contrary, increases from 11.1 mm to 14 mm. 3. The highest muscularity is achieved when the age of the Pjetren and Landrace piglets is within 175-190 days, making respectively 59.9 percent and 56.2 percent. The lowest muscularity in Pjetren piglets standing at 58.5 percent is found at the age of 205-220 days. Among Landrace, the lowest muscularity of 52.4 percent is fixed at the age of 220-235 days. 4. The muscularity of the Yorkshire piglets is the highest at the weight level of 85-90 kg by making respectively 55.6 percent and 54.9 percent. While the weight is increasing, as provided by the... [to full text]