Influences of the number of fetuses and levels of CP and ME in gestation and lactation supplements on performance of Spanish does and kids during suckling and post-weaning

Abstract

Forty-eight mature US Spanish does (40 kg BW), from a herd selected for cashmere fiber growth, were used to investigate influences of the number of fetuses and levels of ME and CP in supplements during gestation and lactation on doe and kid performance. At 60 days of gestation, does with single or twin fetuses consumed mature Bermudagrass hay ad libitum and 1% BW (DM basis) of supplements with 18.6% or 28.5% CP (LP and HP, respectively) and 2.2 or 2.8 Mcal/kg ME (DM basis; LE and HE, respectively). The HE-HP supplement was offered at 1.5% BW (DM basis) for 15 days after birth, and does received the same supplement treatments as in gestation thereafter until weaning at 50 days after parturition. For a 50-day post-weaning period, kids consumed ad libitum the HE-LP supplement. BW at 90 days of gestation (41.4 vs 38.4 kg; P<0.10), BW before parturition (46.1 vs 41.7 kg; P<0.05), BW loss from parturition to day 21 of lactation (8.38 vs 5.25 kg; P<0.05), litter birth weight (5.47 vs 2.75 kg; P<0.05) and plasma concentrations of β-hydroxybutyrate (0.33 vs 0.29 mM; P<0.05) and NEFA (538 vs 434 mEq/l; P<0.05) were greater for does with twin vs single kids. BW at weaning was similar between single and twin kids ( P>0.10; 8.31 and 7.63, respectively). Kid BW and cashmere fiber weight after the post-weaning period were affected by interactions ( P<0.05) between number of fetuses and supplement ME level; kid BW was 12.3, 14.7, 14.6 and 13.2 kg (SE = 1.12 and 0.68 kg for singles and twins, respectively), and kid cashmere weight was 86, 109, 106 and 102 g (SE = 8.5 and 5.0 g for singles and twins, respectively) for single-HE, single-LE, twin-HE and twin-LE, respectively. In conclusion, effects of supplements differing in levels of ME and in ingredient composition for US Spanish does in gestation and lactation had dissimilar impacts on post-weaning BW and cashmere weight of single and twin kids. However, because of the limited number of observations and the high variability among animals in measures such as cashmere fibre growth, further experimentation concerning the potential for effects of nutritional plane of does on cashmere growth by kids is warranted.