Impact of Modern Milk Replacer Formulations on Calf Health and Performance

Within the last ten years there have been major changes in the formulation of calf milk replacers in the United States. These have been brought about by changes in the world supply of milk based ingredients, milk processing technology, vegetable protein processing technology and knowledge of the calf's digestive system. Calf milk replacers manufactured in the 1950's and 1960's contained high levels of skim milk powder as the primary protein source. Skim milk protein consists of approximately 80% casein protein and 20% whey proteins. Provided that the skim milk has not been severely heat treated during the drying process, casein in the milk replacers forms a firm clot or curd in the calf's abomasum. Severely heat treated skim milk does not clot and calves fed milk replacer containing such skim milk suffer from diarrhea and poor performance. Today's modern milk replacers, in the United States, do not contain significant levels of skim milk powder, but either whey proteins or combinations of whey proteins and vegetable proteins, including isolated soy protein, soy protein concentrate, soy flour, isolated wheat protein or potato protein. These milk replacers do not clot in the abomasum and there has been speculation that such non clotting milk replacers may have a negative impact on calf health and performance. Milk Specialties Company has undertaken a series of studies to investigate replacement of skim milk protein in calf milk replacers with whey proteins.