Abstract: This study was carried out to investigate fattening performance and dressing percentage of Holstein crossbred young bulls at different initial live weights in a private farm in Southeastern Anatolia region. The young bulls in the study were divided into three groups according to their initial live weights (123.70, 168.56 and 216.58 kg). Fattening periods, finishing weights, average daily weight gain and feed conversion rate for group I-III were 183.11, 176.72 and 186.25 day, 319.47, 360.68 and 419.04 kg, 1061, 1086 and 1101 g; 7.09, 8.08 and 8.73 kg, respectively. Average daily live weights gain of the groups for whole fattening periods were not significant but average fed conversions ratio of the group were found statistically significant (p<0.05). Dressings percentage of 6 animals from each group at the end of fattening were determined and were 54.40, 54.78 and 54.85% for group I-III, respectively. Group means were not significant. In conclusion, the animals with low initial live weights had a higher fattening performance because they were in the early period of growing.

INTRODUCTION

European cattle were imported in order to increase beef and milk yield in the cattle population of Turkey. These breeds have been a great source of genetic diversity and have been used for crossbreeding throughout the world.

These cattle were raised as purebred and crossed with native breeds in Turkey too. Crossbred animals grow faster, mature at an earlier age and more efficient converter of feed to meat than native breeds (Khan, 1993). Crossbreeding is very successfully being done in developing countries to improve productivity of native stock.

Firstly purebred Holstein (30 females and 17 males) imported from the USA to Turkey in 1958 (Alpan and Aksoy, 2009). Pure and Holstein crossbred have great importance for animal production especially in seaside and Southeastern regions. Turkey’s cattle population is around 11 million and 70% of them are pure improved breeds and their crossbreds with indigenous cattle.

The same data were 143000 and 53%, respectively in the Sanliurfa city of Southeastern Anatolia regio. Main indigenous cattle population of the region is Southeast Anatolian Red (SAR). The SAR has ability for heat, parasite tolerance and to survive with limited food resources (Alpan and Aksoy, 2009). The southeastern Anatolia of Turkey is characterized as humid subtropical and is subject to summer periods of high ambient temperature and low relative humidity (Ekiz et al., 2005). Cattle are among the homoeothermic animals which can continue their body temperatures at a constant level in spite of the changes in the climatic conditions (Yalcin, 1981). For the fattening young bulls to continue this constant body temperature, the most suitable temperatures are in the thermo-neutrality zone of 5-25°C.

The temperatures in this zone do not affect physiological functions negatively. However, at higher temperatures than these limits, stress effect is being observed on farm animals. These conditions cause the fall in the feed intake and decrease in the live weight gain (Akcan et al., 1991; Kocak et al., 1995; Ogan et al., 1997; Ekiz et al., 2005).

Dairy, dual-purpose breeds and their crosses are still the main source of beef in the Turkey. A major part of beef comes from Holstein, Brown swiss and their crossed breeds.

The aim of this study was to determine fattening performance and dressing percentage of Holstein crossbred bulls at different initial weight in sub-tropical climatic and intensive conditions in Sanliurfa city of Southeastern Anatolia region.

MATERIALS AND METHODS

This study was carried out in a private fattening farm in Sanliurfa city in Southeastern Anatolia region of Turkey. The animal materials of this study which were taken in fattening between January and December months were composed of Holstein crossbred young bulls. In the city, the fattening animals are generally bought 8-10 months before feast of the sacrifice and sold 1-30 days before that day. The animals which are sold must be at least 2 years old. This study was carried out to investigate fattening performance and dressing percentage of Holstein crossbred young bulls at different initial live weight in a private farm organizing its time table for feast of the sacrifice. The animals were kept in a semi roofed type of barn and managed under loose housing condition. The climate of Sanliurfa city where the study was conducted is subtropical. The monthly average environmental temperature and humidity values of the region during the dates of the study were collected by Testo electronic device in 2 h intervals and presented as monthly in Table 1.

There were a total of 163 pure and crossbred Holstein young bulls which were fattened in this period. For fattening, young bulls at the age of 6-16 months were bought from other farms and from the city bazaar. The young bulls in the study were divided into three groups according to their initial fattening weights (group I: 95-145 kg, group II: 148-195 kg and group III: 197-265 kg). Before fattening, anti-parasite medicines and vaccinations has been applied and adopted to the feed which would be used for fattening. In fattening, the feed produced in the farm containing of 13-14% crude protein, NDF 38%.5, Ca 0.60%, P 0.40% and 2500-2550 kcal kg^-1 metabolic energy were given ad libitum with free access to water. Feed conversion rates (Roughage+Concentratefeed) which are given in tables were calculated as Dry Matter (DM). During fattening, the animals were weighted monthly by scales sensitive to 100 g. The young bulls which had a chronic illness or under medical treatment for a long time were excluded from the study. Slaughtered and hot dressing weights of 6 animals from each group which were slaughtered in the slaughter house were gathered to investigate the dressings percentage of groups.

Table 1:	Average temperature and humidity values of the private farm

The average initial live weights of the groups were different, so the following weights of the groups were not compared. The data of average daily weight gain and fed conversions ratio were statistically analyzed by using the one way Anova technique and means were compared by Duncan’s multiple-range test (Steel and Torrie, 1981).

RESULTS AND DISCUSSION

The groups had different initial weights and fed for different durations so comparisons of the live weight between groups were not eligible. Comparisons of the groups were focused to daily weight gain and fed conversions ratio.

Average initial live weight, fattening periods, final weights, average daily live weight gain, average fed conversions rate, average hot dressing percentage and their minimum and maximum data for groups have been shown in Table 2. Average daily live weight gains and fed conversions rates of the groups in the different live weights and average daily live weight gains of the whole fattening periods have been shown in Table 3. Final live weights of the groups were different due to different initial live weights.

Average daily live weight gains of the whole fattening periods of the group I-III were 1061.20±45.6, 1086.30±65.2 and 1101.70±74.08, respectively. Analysis of variance revealed that difference between the groups was not statistically significant (p>0.05) during the whole fattening periods.

Similar live weight gains in black and white bulls were also reported by (1016 g) (Alpan et al., 1976), (1076 g) (Akcan et al., 1989), (1023 g) (Ilgu and Gunes, 2002), (1110 and 1120 g) (Baspinar et al., 1999), (1091 g) (Barton et al., 2003) and (1110 and 1120 g) (Lee et al., 2009). On the other hand, higher live weight gains of black and white bulls were found (1330 g) by Ozdogan (2007) and (1336 g) Ekiz et al. (2005).

Muftuoglu et al. (1980) reported in their study that HolsteinxSoutheastern Anatolia red crossbred bulls which were fattened for 135 days with an initial fattening weight of 151, 183 and 230 kg, daily live weight gain of 979, 1065 and 1010 g. Baspinar (1991) determined that the Holsteinxnative black crossbred young bulls groups which were fattened for 292 and 340 days with the average initial fattening weights of 260 and 258 kg had the daily live weight gains of 865 and 873 g, respectively. In this study, average daily live weight gains of the groups between 225-275 and 275-320 kg were found to be significant (p<0.001).

Table 2:	Fattening performance and carcass percentages of the groups

Table 3:	Daily live weight gain and fed conversion rate (DM) between some live weights of groups
Mean values with different letters are significantly different in the same line; * = (p<0.05). *** = (p<0.001). NS = Not Significant; DM = Dry Matter

The average daily live weight gain differences of the fattening groups were shown in Table 3. In the study, heavier live weights animals get the more average daily live weight gain during this period. Differences of the groups in this period probably come from the genotype of the animals and from the different season. The animals in the study were grouped due to their live weights not to their age so, early grooving animals were heavier and settled to group III. Perhaps, these animals would have more daily live weights gain in the grooving period if they were fattened.

Slaughtered weights and hot dressing percentages of 6 animals from each group at the end of fattening which slaughtered were 350.20, 383.56 and 396.20 kg and 54.40, 54.78 and 54.85% for group I-III, respectively. There was no significant statistical difference between hot dressing percentages of the groups. These results were agreement with that reported by some researchers (Barton et al. 2003; Alberti et al., 2008; Sahin et al., 2009) for Holstein.

CONCLUSION

Holstein crossbred bulls in the different initial live weights which were fattened had similar average live weight gain and dressing percentage. But the animals with lower live weight had lower average feed conversion rate for the whole fattening periods.