Livestock Studies 1995, Vol 35, Num, 1-2     (Pages: 001-020)

Effects of different energy levels on feed -lot fattening performance and carcass characteristics of Hoıstein bulls, in winter

Durali KOÇAK 1 ,Satılmıs COŞAR 2 ,Necati TULGAR 1

1 Lalahan Hayvancılık Arastırma Enstitüsü Müdürlüğü, Lalahan -ANKARA
2 Koruma Kontrol Genel Müdürlüğü, Bakanlıklar -ANKARA
- The research was carried out to determine the effects of various energy levels in the concentrates (2.81, 2.92, 3.02 ME. Mcal/kg.DM.) on fattening perforrnance and carcass characteristics of Holstein bulls fed in feed-lot in the Middle Anatolian in winter conditions.

İn this study 18 Holstein bulls, 11 - 15 months of age. were used. The animals were divided in to three groups (Six bulls in each group). The concantrates were fed to animals ad libitum, straw was given limited (1 kg straw/per head daily). The feeding period of the study was 16 weeks.

During the fattening period the average day and night temperature were determined as (3.8) and (-3.2) °C. The highest and lowest temperature was 26°C and -14 °C.

During the fattening period the average daily live weight gain in the groups were 1256, 1215, 1254 g respectively. Dry matter intake (concentrate + straw) for one kg of live weight gain in the groups were 9.346, 9.429, 11.226kg. respectively.

The following mean values were found for the dresstng percentage of warm carcasses 55.52, 56.68, 58.19 %, cold carcasses 54.45, 55.87, 57.30 % the difference between groups was found to be significant (P<0.05). n cold carcasses total meat ratio 75.29, 75.30, 76.60 %, bone ratio 17.56, 18.48, 16.40 %, kidney and pelvis cavity fat 3.84, 4.34,4.09 kg. and M.L.D. fields 86.42, 90.70, 102.25 cm² were determined in the groups respectively .

The result indicated that, a proper ration may ensure high fattening performance within the genetic capacity of cattle in the winter time of central Anatolia, in feed lot system. Keywords : Holstein bulls, energy, feed-lot in winter, performance, carcass charecteristics