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

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 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