This study investigated the effects of different protein levels on growth performance, feed efficiency, and morphological traits in female and male Boer × Korean native crossbred goats (Capra hircus) raised in Korea. A total of twenty-four goats (12 per sex) with an average age of seven months were included in the experiment. The initial body weights (BW) were 31.0 ± 0.6 kg for females and 27.4 ± 1.5 kg for males. A randomized block design was used with three dietary crude protein (CP) treatments: 15% (T1), 18% (T2), and 21% (T3). The results demonstrated that, in female goats, no significant differences (p>0.05) were observed in most growth parameters, except for dry matter intake (DMI), which was significantly higher in T2 and T3 (p<0.05). The total weight gain (TWG) was 2.2 kg in both T1 and T2, and 2.8 kg in T3. The average daily gain (ADG) in females reached 82 g/d in T3, significantly higher than the other. In male goats, DMI was also greater in T2 and T3 compared to T1, with the highest TWG (4.4 kg) and ADG (126.9 g/d) recorded in T3, surpassing the other treatments. Regarding morphological traits, female goats in T3 exhibited significantly greater body length (66.9 cm), withers height (62.8 cm), and chest girth (19.3 cm) compared with T1 and T2 (p<0.05). In contrast, male goats in T2 showed superior body length (65.6 cm), chest width (20.1 cm), and chest girth (78.5 cm) (p<0.05). In conclusion, the study indicates that higher protein levels (21% CP) enhance growth performance and morphological development in female goats, whereas a moderate level (18% CP) appears to be more effective for male goats. These findings suggest that protein requirements differ by sex, and sex-specific feeding strategies should be considered to optimize growth and body conformation in crossbred goats.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. MATERIALS AND METHODS
    1. Experimental design and feeding management
    2. Data collection and measurements
    3. Chemical composition analysis
    4. Statistical analysis
Ⅲ. RESULTS AND DISCUSSION
    1. Effect of dietary protein levels on growth performancein female goats
    2. Effect of dietary protein levels on growth performancein male goats
    3. Effect of dietary protein levels on morphological traitsof female goats
    4. Effect of dietary protein levels on morphological traitsof male goats
Ⅳ. CONCLUSIONS
Ⅴ. ACKNOWLEDGEMENTS
Ⅵ. REFERENCES

• Kwan-Woo Kim(Animal Genetics Resources Research Center, National Institute of Animal Science, RDA, Hamyang 50000, Republic of Korea)
• Eun-Do Lee(Animal Genetics Resources Research Center, National Institute of Animal Science, RDA, Hamyang 50000, Republic of Korea)
• Dong-Kyo Kim(Animal Genetics Resources Research Center, National Institute of Animal Science, RDA, Hamyang 50000, Republic of Korea)
• Hee Chung Ji(Animal Genetics Resources Research Center, National Institute of Animal Science, RDA, Hamyang 50000, Republic of Korea)
• Bong-Hwan Choi(Animal Genetics Resources Research Center, National Institute of Animal Science, RDA, Hamyang 50000, Republic of Korea)
• Ga-Eun Kim(Animal Genetics Resources Research Center, National Institute of Animal Science, RDA, Hamyang 50000, Republic of Korea)
• Byamungu Mayange Tomple(Animal Genetics Resources Research Center, National Institute of Animal Science, RDA, Hamyang 50000, Republic of Korea) Corresponding author