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1. Groups of kids were reared from birth to 5 d on goat's milk. On the 6th day five of the kids received by bottle a morning feed of goat's milk with [3H]folic acid added to saturate the folate-binding proteins (FBP) (Expt 1); three kids received raw goat's milk containing only the endogenous folate and hence a large surplus folate-binding capacity (FBC) (Expt 2). The contents of the stomach, duodenum, jejunum and ileum were recovered by washing out 1·5 h after feeding (Expt 1) or at 0·5, 1 and 3·5 h after feeding (Expt 2).2. Recovery of [3H]folic acid 1·5 h after feeding (Expt 1) in all segments was 58·4%, mainly in a soluble form, most of this being in the stomach (37·0%) and ileum (14·3%). No surplus FBC was found in any gut segment. Sephadex G-75 chromatography of the soluble fractions of the contents of the various gut segments showed that [3H]folic acid remained bound to FBP throughout the stomach and small intestine. The bound [3H]folic acid exhibited a molecular weight of 81000 in stomach contents, similar to that in the milk feed, presumably representing an aggregated form of the FBP, whereas in the intestinal contents its molecular weight was 39000 indicating dissociation to monomer due to dilution in the recovery process.3. In Expt 2, the total recovery of free FBP in all four gut segments was 67, 54 and 23% respectively at 0·5, 1 and 3·5 h after the milk feed, and the distribution of FBP along the gut at 1 h was similar to that of [3H]folic acid-labelled FBP at 1·5 h in Expt 1. In mature goat's milk the endogenous 5-methyltetrahydrofolate was shown to be associated with species of molecular weight 80000 and 38000.4. The results indicate that goat's-milk FBP is relatively resistant to digestionby gastric and intestinal enzymes in vivo in the kid and survives along the length of thesmall intestine.5. The implications of the findings are discussed in relation to the possible influence of FBP on uptake of folate by mucosal cells and their relevance to neonatal folate nutrition.

During the first 2 weeks after kidding, 27 multiparous British Saanen goats were offered 1·5 kg hay (98 g crude protein (CP) per kg dry matter (DM)) and from 0·45 increasing to 0·70 kg concentrates (152 g CP per kg DM) daily. Week 2 was used as a covariance period. At week 3 of lactation all the goats were allocated to one of three groups and were offered hay ad libitum and 1 kg concentrates containing 117 (LP), 152 (MP) or 185 (HP) g CP per kg DM daily to week 15. During weeks 4 to 15, hay intake and milk yield were highest in the HP group. With increasing protein in the concentrates, hay DM intake was 1·20, 1·19 and 1·37 (s.e. 0·060) kg/day respectively and milk yield was 3·04, 3·21 and 3·36 (s.e. 0·080) kg/day respectively (linear response P < 001). There was no significant effect on the concentration of solids-not-fat, fat, total nitrogen or casein in milk. The digestibility of dietary organic matter, acid-detergent fibre and total nitrogen measured after week 15 was significantly greater with HP than with LP (P < 0·05), with MP values being intermediate (linear response P < 005). The rate of passage of ytterbium-labelled hay was unaffected by the treatments. The results indicate that, with lactating goats given hay and concentrates, beneficial responses may be expected to increasing concentrate CP to at least 185 g CP per kg DM.

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The different feeding treatments, which affected the fatty acids profile, did not affect the sensory quality of the meat as found by tasting panels. The tasting panels rated samples of meat from 1-7 for aroma, flavor, hardness and juiciness. There were no statistically significant differences between the groups in neither of the above parameters. Intake of concentrates by S kids increased from a mean 850 g/day during gain from 21-29 kg to 1 130 g/day in the interval from 37-45 kg but intake relative to liveweight decreased from 35 to 28 g/kg, a little lower than those of lambs on a similar diet. The growth rate only declined very slightly over the three growth intervals but conversion efficiency decreased by 28 %. The A x S kids had lower intakes, growth rates and efficiencies of conversion than S kids.