The effect of diet in late pregnancy on colostrum production and immunoglobulin absorption in sheep

Abstract

AbstractOne hundred and twenty-six twin-bearing ewes were given either formic acid (FA) treated grass silage or grass/ molassed sugar-beet pulp (MSBP) silage in order to investigate factors affecting colostrum yield and quality and the efficiency of immunoglobulin (IgG) absorption. The experiment commenced on day 91 of pregnancy and the diets consisted ofFA-treated silage (Tl), FA-treated silage + soya-bean meal (SB) (72), MSBP silage (T3), MSBP silage + SB (T4), FA-treated silage + MSBP (T5), FA-treated silage + MSBP + SB (T6) or FA-treated silage + 150 g/kg of a crude protein concentrate (T7). Soya-bean meal was offered only in the last 3 weeks of pregnancy aiming for a total crude protein intake of220 g per ewe per day. Blood samples were taken from lambs in order to measure serum Ig concentrations. Ewes were milked at 1 h,10h and 18 h post lambing. Daily metabolizable energy intakes of 6·8, 11·4, 9·6, 12·8, 10·5, 13·7 and 14·7 (s.e. 0·58) M] per ewe were recorded for Tl to T7 respectively over the last 3 weeks of pregnancy. Respective crude protein intakes of 72, 213, 110, 225, 109, 215 and 175 (s.e. 5·64) g per ewe per day were recorded for Tl to T7 over the last 3 weeks of pregnancy. The addition of protein increased colostrum yield at 1 h (P < 0·01), 10 h (P < 0·01) and 18 h (P < 0·01) post lambing and total yield of colostrum to 18 h (P < 0·001). There was no significant response (P > 0·05) in colostrum production during the first 18 h following protein supplementation when the basic diet was FA-treated silage. There was no difference (P > 0·05) in colostrum production during the first 18 h between ewes offered MSBP treated silage or MSBP supplemented silage. Ewes offered FA-treated silage produced less colostrum during the first 18 h compared with ewes offered either MSBP treated or supplemented silage (P < 0·05). The production of colostral IgG during the first 18 h after parturition was related to the amount of colostrum produced; the greater the colostrum production the greater the Ig production. There was a significant quadratic relationship between the total amount of IgG ingested per kg lamb birth weight during the first 18 h and lamb serum IgG at 24 h (R2 = 0·4005; P < 0·0001). Lamb serum Ig level increased linearly with increasing colostrum IgG consumption up to 15 g/kg lamb birth weight. Proportionately about 0·17 of the IgG ingested was present in the lamb's circulation at 24 h. Ewe protein supplementation pre-lambing increased the lamb's efficiency to absorb colostral IgG (P < 0·05) during the first 24 h. In conclusion, the data show positive relationships between feeding regimes, colostrum production and IgG transfer.