Short communication: reproductive response to concentrate supplementation of mixed-breed goats on rangeland

• Published in: Tropical animal health and production Vol. 52; no. 5; pp. 2737 - 2741
• Main Authors: Mellado, Miguel, Rodríguez, Iris J., Alvarado-Espino, Alan, Véliz, Francisco G., Mellado, Jesús, García, José E.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-09-2020; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Body mass; Breeding; Cortisol; Fertility; Flushing; Gestation; Goats; Life Sciences; Malnutrition; Pregnancy; Rangelands; Reproduction; Short Communications; Supplements; Thyroid hormones; Triiodothyronine; Urea; Veterinary Medicine/Veterinary Science; Zoology; Pregnancy rate; Litter size; Fetal losses; Litter weight; Grazing goats
• ISSN: 0049-4747; 1573-7438
• DOI: 10.1007/s11250-020-02264-z

The effect of concentrate supplementation to crossbred goats on rangeland during the dry period on their reproductive performance was investigated. Goats were assigned into two groups: a concentrate supplemented (S;
n
 = 91) group and an unsupplemented (UNS;
n
 = 118) group. S goats received 350 g/day of concentrate per head, 30 days prior to breeding (flushing in winter) and 30 days during the last trimester of pregnancy. UNS goats presented a lower (
P <
 0.01) liveweight at the onset of the breeding period than did the S group (38.2 ± 3.7 vs. 44.4 ± 3.6 kg). Average daily gains during pregnancy were higher (
P <
 0.01) in the S group than UNS goats (15.5 ± 1.2 vs. − 0.5 ± 5.1 g/d). S goats had a higher (
P <
 0.01) kidding rate (87.1%) than the UNS goats (54.7%). Litter size for UNS and S goats was 1.39 and 2.00, respectively (
P <
 0.01). Serum triiodothyronine, tetraiodothyronine, and cortisol concentration at the end of the flushing period were not affected by concentrate supplementation. Serum glucose (88.7 ± 3.8 vs. 95.7 ± 5.3 mg/dL), total protein (6.9 ± 1.1 vs. 8.2 ± 1.2 mg/dL), and blood urea nitrogen (17.1 vs. 21.0 ± 4.3 mg/dL) concentrations were lower for UNS goats as compared with S goats. In conclusion, concentrate supplementation in crossbred goats on rangeland markedly improved body mass changes during gestation and the reproductive performance, which implies that malnutrition is a major barrier affecting fertility of goats and liveweight of kids in this rangeland.