45 Net macromineral requirements for maintenance in male and female Saanen goats: A meta-analytical approach

The objective of this study was to evaluate sex effects on the daily net requirements of calcium (NCam), phosphorus (NPm), magnesium (NMgm), and potassium (NKm) for maintenance in Saanen goats of 5 to 45 kg BW. For this purpose, two datasets were used: the first dataset was composed of 154 individual records (53 castrated males, 46 females, and 55 intact males) from three comparative slaughter studies, and was used to test the sex effects on NCam, NPm, NMgm, NKm in Saanen goats, using the comparative slaughter technique (CST). The second dataset was assembled from 155 individual records (67 castrated males, 40 females, and 48 intact males) from four feeding trials, and was used to evaluate the sex effects on NCam, NMgm, and NKm in Saanen goats, using the minimum endogenous losses method (MEL). The meta-analyses were performed using a mixed model, in which sex was considered a fixed effect and study a random effect. Sex did not affect NCam, NPm, and NKm in Saanen goats of 5 to 45 kg BW, when mineral requirements were estimated using CST (P > 0.10). The NCam, NPm, and NKm were 21.1, 22.8, and 4.0 mg/kg BW, respectively. In contrast, sex affected the NMgm of Saanen goats (P = 0.077). The NMgm for castrated male and female Saanen goats was 1.4 mg/kg BW, while for intact males, NMgm was 2.6 mg/kg BW. Sex did not affect the NCam, NMgm, or NKm in Saanen goats of 5 to 45 kg BW, when mineral requirements were estimated using MEL (P > 0.10). The NCam, NMgm, and NKm were 38.0, 7.4, and 25.2 mg/kg BW, respectively. The daily net macromineral requirements for maintenance reported herein may be relevant for the development of feeding systems for goats, and for optimizing mineral nutrition management of growing Saanen goats. Key Words