Plant vs. Animal Protein as a Source of Supplemental Protein for the Gilt

Protein of animal origin has frequently been suggested to have greater nutritional value for swine reproduction than protein of plant origin. Moustgaard (1952) reported that gilts fed a diet in which the supplemental protein was of animal origin (soured separated milk) reached puberty earlier and had a greater ovulation rate and greater embryo survival and litter size at 26 to 29 days of gestation than gilts fed a diet in which the supplemental animal protein was replaced with protein of plant origin. Most of the advantage of the animal protein diet was eliminated when the all-plant diet was supplemented with vitamin B12. Fowler and Robertson (1954) reported similar advantages in age at puberty, ovulation rate and litter size from replacing 50% of the supplemental plant protein with protein of animal origin. These differences were markedly reduced when an antibiotic-vitamin B12 supplement was added to the all-plant diet