Signs of slaughtering bulls meat breed Ukrainian

Анотація

At the present stage of the beef cattle breeding it is important to know the features of the formation of animals’ meat productivity in ontogenesis to efficient and purposeful produce beef with a large percentage of the valuable components. Therefore, the aim of the article is to study out the indication of slaughter of animals of Ukrainian meat breeds at different ages.

Data on meat productivity of bullocks at the plant "Volia" (Cherkasy region) served as a study material. At the age of 8 months animals were put to study on their own productivity that lasted up to the age of 23 months. A process of forming of groups of animals for slaughter was based on the balanced group-analog method. To determine meatiness of animals they considered a  muscle-bone ratio (MBR), muscle index (MI), index of meatiness (IM), net gain (a carcass weight increases at a rate of one day of life).

At the age of 18-21 months a slaughter weight of bullocks increases by 19.4%. The highest slaughter output is observed at the age of 21-st month. High indicators of a slaughter output at the age of 21-st months and relatively low at the age of 23 months are caused by a low growth of live weight and a carcass weight in the first case and larger internal fat deposition in the second one. The indicators of a net gain of bullocks evenly decreases with age: it is the highest from the very birth up to 18 months; from birth up to 23 months it reduces.

Other factors that do not affect the slaughter output include organs and body parts of animals that are considered not to be a part of the carcass  (such as head, legs, internal organs and skin). The 21-month-old bullocks, which are characterized by the highest slaughter output have relatively larger weight of heads, skin and less scrap of meat and fat. Among the internal organs the most distinguished weight has a liver. A ratio of the guts to a live weight after starving reduces at the age of 18-23 months. The relative weight increase of the rest of the internal organs in the period under study is not even. Sizes of bullocks’ skin do not change significantly with age.

With the age a weight of animals’ carcasses increases, and the ratio of different tissues changes as well (muscle, fat, connective and bone tissues). Along with the increase of the total weight a change of the rate of growth of muscle tissue is observed. Its output increases at the age of 21 months by 17.2%, and at the age of 23 months when the fat content in carcass increases - only by 2.6%. The content of a  muscle tissue of the higher grade with age tends to increase, the second grade - to decrease.

Output of a muscle tissue of the meat of higher grades (top + first) at the of 23 months is higher by 15.7% compared with animals of the age of 18 months. Output of bones in the carcasses of bullocks is in the range of 16.9 to 17.6%. This indicators decrease with age.

Index of meatiness (IM) is in the range of 4.4 to 4.7. Its quantity tends to increase as animals grow. The changes in the muscle tissue index (MTI) were not found. At the age of 21 months animals’ muscle tissue index is slightly higher. With the change of the age of the animals one trace a tendency of increase of the ratio of muscle and bone tissues, but muscle tissue is growing faster than the bone one.

The biggest change in the period of growth of animals shows an adipose tissue. Increase  of its content in carcass is accompanied with an inversely proportional decrease in other fat depots. Its significant proportion (about 70%) is explained by the animals’ biological feature to contain nutrients in conditions of  intensive feeding and spend them in unfavorable periods, and changes in metabolism. The highest content of internal fat is at the age of 23 months. Its deposition in the proventriculus and adrenal glands increases, especially in the period at the age of 21-23 months. Heart adipose tissue is characterized with the smallest growth rates.