The effect of dietary protein source on the metabolism and performance of ewes in late pregnancy and early lactation

Handford, David (2001). The effect of dietary protein source on the metabolism and performance of ewes in late pregnancy and early lactation. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000fd01

Abstract

Three experiments were carried out to investigate the effects of dietary protein source on the metabolism and performance of straw fed, twin-bearing ewes in late pregnancy and early lactation. In the first experiment, 72 ewes were fed concentrate diets which contained either fishmeal or formaldehyde treated soya-bean meal. The concentrate was either fed alone, or at a reduced rate with feedblocks ad libitum in a two by two factorial design. Ewes fed fishmeal lost more condition after parturition and had lambs which grew quicker than ewes fed treated soya-bean meal (P<0.05). Ewes offered feedblocks produced colostrum with a higher immunoglobulin G (IgG) concentration at birth, had lambs with a higher litter weight than those fed concentrate alone (P<0.05). In the second experiment, 60 ewes were fed concentrates containing either untreated or formaldehyde treated rapeseed meal or field beans in a two by two factorial design with an additional control diet containing fishmeal. Ewes fed fishmeal had a higherpre partum condition score gain and had lambs which grew slower with a lower litter weight at 28 days than ewes fed all other diets. Ewes fed rapeseed meal had a higher total colostrum yield at birth than ewes fed field beans (P<0.05). Ewes fed formaldehyde treated protein sources had a reduced yield of total milk, protein, solids not fat and lactose at 21 days post partum than ewes fed untreated protein sources (P<0.05). In the third experiment, 44 ewes were fed concentrate diets containing either fishmeal, untreated soya-bean meal, formaldehyde treated soya-bean meal or formaldehyde treated soya-bean meal with added rumen protected methionine. Ewes fed formaldehyde treated soya-bean meal with added methionine produced colostrum between 12 and 16 hours post partum with a higher fat concentration and a higher yield of fat and crude protein than ewes fed fishmeal (P<0.05). Ewes fed formaldehyde treated soya-bean meal with added methionine had lambs which grew quicker and were heavier at 28 days of age than those fed fishmeal (P<0.05).