Abstract: This study examined the effects of early castration on slaughter and carcass characteristics of Norduz goat male kids. Animal material consisted of 25 male kids divided into two groups-an early castrated group (n = 13) and a control group (n = 12). All animals were weaned at 3 months and then subjected to an 85 days fattening period. Kids were fed with a ration of concentrate (16.6% crude protein and 10.6 MJ kg^-1 DM ME) ad libitum +200 g sainfoin per kid twice daily. At the end of the fattening period, eight kids from each group were slaughtered to determine carcass characteristics. Significant differences (p<0.01) were found in the slaughter weights of castrated (24.84±0.465 kg) and intact (30.41±1.061 kg) kids. Cold carcass weights of castrated (9.40±0.230 kg) and intact (11.53±0.544 kg) kids also varied significantly (p<0.05). Muscle, bone, subcutaneous fat and intermuscular fat percentages in the chop region for intact and castrated groups were, respectively, 43.15±0.822 and 41.48±0.579%; 24.60±1.026 and 26.84±0.750%; 7.66±0.711 and 10.21±0.615%; 7.48±0.506 and 7.25±0.693%. It was concluded that early castration had no significant on the carcass characteristics of Norduz male kids.

INTRODUCTION

When compared to other ruminants, goats are better able to tolerate unfavourable management and maintenance conditions, making the raising of goats preferable and more widespread in many developing regions, especially in the Mediterranean. Overall, >95% of the goat population is found in developing and underdeveloped countries, compared to <5% in developed countries (Daskiran et al., 2006).

In Turkey, goat meat accounts for only 6.8% of total red meat consumption. In comparison to sheep and cattle meat, goat meat is lower in fat and cholesterol content. While high protein and low fat content makes goat meat an important source of human nutrition, its low fat content is a disadvantage in terms of juiciness, flavour and tenderness.

Meat quality is influenced by various factors that include genotype, sex, age and feeding conditions (Johnson and McGowanb, 1998; Boyazoglu and Morand-Fehr, 2001). Castration of male kids is performed to improve growth rates, feed efficiency and meat quality as well as to reduce unwanted odours released by hormonal circuits. Castrated kids have been shown to have lower percentages of muscle tissue and higher percentages of fat tissue than intact kids (Morand-Fehr et al., 1991). Louca et al. (1977) and Kor have shown that flavour and tenderness of castrated kid meat can be improved by increasing the amount of intermuscular fat content. However, Kor and Coban reported that the impact of castration on fattening is not significant.

It is possible that the age of castration may have an effect on meat quality and growing rates. However in comparison to other species, few studies have been conducted on goatsand the effects of castration at different ages have not been fully elucidated. To the best of our knowledge, no study related to castration has been conducted with Norduz goat male kids. Therefore, this study aimed to determine the effects of early castration on slaughter and carcass characteristics of Norduz goat male kids.

MATERIALS AND METHODS

The study was conducted at the Yuzuncu Yil University Agricultural Faculty Research Farm in Van, Turkey with 25 local Norduz male kids. Kids were randomly separated into two groupsand the kids in one group (n = 13) were castrated at 1 week of age using elastrator rings while the other group (n = 12) was left intact. Feeding and management practices were applied equally to all kids. All animals were weaned at 3 months and then subjected to an 85 days fattening period in semi-open pens. Each kid was offered a diet of concentrate (16.6% crude protein and 10.6 MJ kg^-1 DM ME) ad-libitum and 200 g sainfoin twice daily.

At the end of the fattening period, eight kids from each group were slaughtered to determine carcass characteristics. Hot carcass, skin, head, four feet, omental fat, heart, lungs and spleen weights were recorded immediately after dressing.

Carcasses were then refrigerated 4°C for 24 h and cold carcass weights were recorded. Carcasses were then separated into joints according to the standard method for goat carcass evaluation in Mediterranean Countries (Colomer-Rocher et al., 1987) and each joint was weighed separately. Chop joints (the 6th-12th ribs) were dissected into muscle, bone and fat for weighing, with subcutaneous and intermuscular fat depots recorded separately.

Data was analyzed using one-way analysis of variance (Minitab 13.0) according to the following model:

Where:

RESULTS AND DISCUSSION

Kids were slaughtered after an 85 day fattening period to determine carcass characteristics and slaughtering traits. Slaughter and hot carcass weights are shown in Table 1.

Statistically significant differences were found in the slaughter (p<0.01) and four feet weights (p<0.05) and the hot carcass, head and skin weights (p<0.01) of intact males and castrates. However, no significant differences were found in dressing percentages, omental and mesenteric fat, heart, lung or spleen weights. Hot dressing percentages for the intact group and castrated group were 38.72±0.602 and 38.74±0.325%, respectively. Dressing percentages of different breeds of goat kids have been reported to be around 46-48% (Nitter, 1975; Hogg et al., 1992; Koyuncu et al., 2007), although lower dressing percentages have been reported for 3-5 months old Sudan Desert male kids fattened on pasture and Native Hair goat male kids (38.7 and 39.40%, respectively) (El-Hag et al., 2007).

Table 1:	Slaughter characteristics of castrated and intact Norduz goat kids (n = 8)
*: p<0.05, **: p<0.01, NS: Not Significant; Values are expressed as

Table 2:	Cold carcass characteristics and left-side joint weights (n = 8)
p<0.05, **: p<0.01, NS: Not Significant; Values are expressed as

In the present study, no significant differences were found in the mean omental and mesenteric fat depots between the two groups. Omental and mesenteric fat measurements in this study were lower than those of some previous studies (Bayraktaroglu et al., 1988; Hogg et al., 1992; Kor et al., 2004) but higher than those of others (Kebede et al., 2008). Omental and mesenteric fat are some of the most important slaughter parameters. Whereas, muscle and bone development occurs at a slow pace in fattening goat kids, visceral fat depots (omental, mesenteric, perineal and pericardic fat) accumulate more quickly (Anonymous, 1988). Cold carcass (4°C at 24 h) characteristics are shown in Table 2.

Kidney knob and channel fat are two important characteristics of goat carcasses. This study found kidney knob and channel fat of intact male kids to be higher than those of castratesbut the difference between the two were not significant. Kidney and channel fat amounts in this study were similar to those found in some earlier studies (Aydin and Arik, 1999) but higher than those of other studies. Distributions of left-half carcass joints (%) are shown in Table 3.

With the exception of the neck joint (p<0.05), no significant differences were found in joint percentages between the two groups. Carcass joint percentages in this study were similar to those of some previous studies (Daskiran, 1992; Aydin and Arik, 1999; Kor et al., 2004; Koyuncu et al., 2007) but lower than those of others (Kor and Ertugrul, 2000).

Table 3:	Distribution of carcass joints (%) (n = 8)
*: p<0.05, **: p<0.01, NS: Not Significant; Values are expressed as

Table 4:	Tissue distribution (%) of chop region (Rib 6-12) (n = 8)
A Includes weight loss during dissection and minor tissue loss (nerves, tendons, lymph nodes, etc.) *: p<0.05, NS: Not Significant; Values are expressed as

Whole and half-carcass tissue analysis requires a significant amount of time that reduces meat quality and results in economic loss. Crouse and Dikeman (1974) reported that tissue analysis of the chop region (ribs 6-12) can provide satisfactory results with less time and effort than whole or half-carcass tissue analysis. Therefore, this study conducted tissue analysis on the chop joint only (Table 4).

Significant differences were found in the percentages of subcutaneous fat and total fat (subcutaneous+intermuscular fat) between the two groups (p<0.05). No significant differences were found between the two groups in percentages of muscle, boneintermuscular fat or losses (i.e., weight loss during dissection and loss of nerves, tendons, lymph nodes and other minor tissue). Muscle percentages in this study were lower than those of some previous studies (Smith et al., 1982; Daskiran et al., 2006; Koyuncu et al., 2007) whereas bone percentages were higher than one previous study conducted with Angora and Spanish goats (Smith et al., 1982) but lower than another study conducted with Norduz goat male kids (Daskiran et al., 2006).

CONCLUSION

The findings of this study indicate that early castration does not have a significant impact on carcass characteristics of Norduz goat kids. In what may be considered an advantage for generally fatless and hard goat meat, this study found chop joints of castrated kids to have a higher percentage of fat than those of intact kids. Given the variety of conflicting reports regarding the effects of castration on goat meat yields, additional studies should continue to be conducted.

ACKNOWLEDGEMENTS

This research was summarized from the master thesis of first researcher in this study. We would like to thank the Yuzuncu Yil University Research Farm manager for the experimental support.