### Abstract

A database of 349 treatment mean observations, representing 3404 goats from 73 publications between 1973 and 2003, was used to determine metabolizable protein (MP) requirements for maintenance (MP_{m}) and growth (MP _{g}) of goats. Published CP degradation properties of feedstuffs and proportions of dietary ingredients were used to estimate MP intake (MPI, g/day), which was regressed against ADG, with both variables scaled by BW ^{0.75}. Goats were classified as meat (≥50% Boer; 60 observations), dairy (selected for milk production; 129 observations) and indigenous (160 observations) biotypes. Because of differences (P<0.01) among biotypes in slopes, separate regressions were initially performed - meat: MPI=2.55(S.E.=0.360)+(0.441(S.E.=0.0276)×ADG) (n=58;R^{2}=0.82); dairy: MPI=2.83(S.E.=0.344)+(0.299(S.E.=0.0238)×ADG) (n=123;R ^{2}=0.57); and indigenous: MPI=3.23(S.E.=0.212)+(0.281(S.E.=0.0304) ×ADG) (n=152;R^{2}=0.36). Intercepts did not differ among biotypes (P=0.37), but the slope for meat goats differed (P<0.01) from those for dairy and indigenous goats; therefore, data sets for dairy and indigenous goats were pooled and split into development (n=150) and evaluation (n=125) subsets. Using the equation derived from the development data subset for dairy and indigenous goats (i.e., MPI=3.14(S.E.=0.189)+(0.285(S.E.=0.0168)×ADG) (n=144;R^{2}=0.67)), MPI for the evaluation subset was predicted; regressing observed against predicted MPI of the evaluation data subset resulted in an intercept and slope not different from 0 and 1, respectively (P>0.05). The equation from the development subset for dairy and indigenous goats was compared with the equation from the meat goat data set; there was a difference (P<0.01) in slopes but not in intercepts (P=0.25). Therefore, a dummy variable (D=1 for meat goats and 0 otherwise) was used to develop a common intercept equation: MPI=3.07(S.E.=0.165)+(0.290(S.E.=0.0150)×ADG)+(0. 114(S.E.=0.0162)×D×ADG) (n=202;R^{2}=0.75). In conclusion, based on regression of MPI against ADG, MP_{m} was 3.07 g/kg BW ^{0.75} for all biotypes of growing goats, and MP_{g} was 0.404 and 0.290 g/g ADG for meat and other (dairy and indigenous) goats, respectively.

Original language | English |
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Pages (from-to) | 309-326 |

Number of pages | 18 |

Journal | Small Ruminant Research |

Volume | 53 |

Issue number | 3 |

DOIs | |

State | Published - Jul 2004 |

### Keywords

- Goat
- Growth
- Maintenance
- Metabolizable protein

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## Cite this

*Small Ruminant Research*,

*53*(3), 309-326. https://doi.org/10.1016/j.smallrumres.2004.04.003