Effects of starter protein content and alkali processing of wheat straw on growth, ruminal fermentation, and behavior in Holstein calves

The present study was conducted to investigate the effects of crude protein (CP) content starter feed and wheat straw (WS) processing on growth performance, digestibility, ruminal fermentation, behavior Holstein calves. Sixty calves (28 male 32 female) were randomly assigned 1 4 treatments in a randomized complete block design. Treatments 2 × factorial arrangement (1) lower-CP ground mixed with alkali-processed WS (LP-PWS), (2) unprocessed (LP-WS), (3) higher-CP (HP-PWS), (4) (HP-WS). Wheat fed at 4.75% dry matter (DM), low-protein (LP) high-protein (HP) contained 19.5 23.5% CP, respectively. weaned d 60 remained until 75. During experiment, received 4.2 kg whole milk per day had free access fresh water feed. interaction between tended be significant for intake, average daily gain (ADG), body weight (BW); HP-PWS have greater ADG final BW than other treatments. results showed that feeding HP increased efficiency compared LP groups during preweaning overall periods. Moreover, weaning higher HP-fed LP-fed Apparent digestibilities acid detergent fiber (ADF), starch, CP rumen propionate ammonia concentrations. no effect intake but DM, ADF, neutral decreased pH. Using processed (PWS) decrease rumination time acetate concentration Final barrel withers height PWS. Overall, indicated (23.5%) could recommended Furthermore, PWS inclusion diet digestibility calf performance.