Growth performance, nutrient utilization, and health of dairy calves supplemented with condensed whey solubles

摘要

Our objective was to evaluate growth performance,nutrient utilization, and health of calves supplementedwith condensed whey solubles (CWS). Twenty-fourHolstein calves (2 d old) in hutches were used in a12-wk randomized complete block design study. Calveswere blocked by birth date and sex. Treatments were(1) control (CON) with no supplement and (2) 50g/d of CWS. Preweaning CWS was fed with milk andpostweaning CWS was top-dressed on starter pellets.Calves were fed 2.83 L of pasteurized milk 2×/d duringwk 1 to 5, 1×/d in wk 6, and weaned at d 42.Calves had ad libitum access to starter pellets and water.Individual intakes of milk and starter pellets weremeasured daily. Fecal scores (0 = firm, 3 = watery)and respiratory scores (healthy ≤3, sick ≥5), calculatedfrom the sum of scores for rectal temperature,cough, ocular, and nasal discharge, were recorded daily.Body weights (BW), frame growth, and jugular bloodsamples were taken once every week at 3 h after themorning feeding. Fecal grab samples were collected inwk 12 for analysis of apparent total-tract digestibility.Data were analyzed using MIXED procedures of SAS9.4 (SAS Institute Inc., Cary, NC) with repeated measures.Total dry matter intake was greater in calves fedCWS compared with CON. Calves fed CWS tendedto have greater BW during the postweaning period.Gain: feed, average daily gains, withers heights, andconcentrations of plasma urea nitrogen were not different.Concentrations of plasma β-hydroxybutyrate weregreater in calves fed CWS compared with CON. Serumglucose concentrations were greater in calves fed CONduring the preweaning stage, but similar concentrationswere found between treatments during the postweaningstage. Rumen pH, ammonia-N, and total volatile fattyacids were similar between treatments. The acetate:propionate ratio was greater in calves fed CWS. Theapparent total-tract digestion of nutrients was similar;however, CON tended to have greater digestion of neutraldetergent fiber. Fecal scores were not different, buta treatment by week interaction was observed. SupplementingCWS improved starter intake, postweaningBW, β-hydroxybutyrate, fecal scores, and maintainedframe growth.