COMPARISON OF FISH PROTEIN SOURCES AND MILK BY-PRODUCTS IN MILK REPLACERS FOR CALVES

Abstract

Three fish protein sources and milk by-products were used in milk replacers. Thirty Holstein heifer calves were fed five different milk replacers as follows: all-milk nitrogen control, and four with 65% of the nitrogen supplied by steam-dried herring meal and the remaining nitrogen from milk as: (a) skim milk powder, (b) skim milk and acid whey powders; and (c) acid whey powder partially neutralized with NaOH or (d) Ca(OH)2. Body weight gains were greater for calves fed the control milk replacer; from birth to 26 wk of age, calves weaned from this milk replacer gained 822 g/day, compared with 662, 731, 741 and 699 g/day, respectively, on diets a to d noted above (P < 0.05). A digestion and nitrogen balance trial with four bull calves fed the four herring meal milk replacers in a 4 × 4 latin square showed relatively poor utilization of the herring meal, especially for calves at 2–4 wk of age. The apparent dry matter digestibility was 75% when the acid whey in the diet was neutralized with Ca(OH)2, compared with 81% when it was neutralized with NaOH. Three milk replacers containing 62% of the total nitrogen from herring meal, isopropanol-extracted fish protein concentrate (FPC), or predigested FPC were compared using six Holstein bull calves in two 3 × 3 latin squares. Apparent digestion of dry matter and energy by the calves was similar for the three diets. Nitrogen digestibility was 82% in the herring meal and 86% in the predigested FPC diet (P < 0.05). At the end of the digestion trial, the calves were continued on the same diet to 91 kg body weight. Body weight gains by all calves averaged 1 kg/day. Loin roasts from the calves fed the herring meal diet were tougher and had an objectionable odor compared with those from calves fed the two FPC diets or whole milk. It was concluded that FPC could be a useful ingredient in calf milk replacers, and that herring meal was not well utilized by calves at 2–4 wk of age.