Inclusion of psyllium in milk replacer for neonatal calves. 2. Effects on volatile fatty acid concentrations, microbial populations, and gastrointestinal tract size.

Fermentable fibers such as psyllium increase volatile fatty acid (VFA) concentrations in the lower digestive tract and increase the gastrointestinal tract (GIT) mass of many mammals. We reasoned that psyllium inclusion in milk replacer might produce similar effects in neonatal dairy calves, which could lead to improved growth and health. Male Holstein calves were fed a milk replacer (22% crude protein, 20% fat) either without or with psyllium (1.1% of dry matter, DM) from 2 d through 28 d of age. Milk replacer was reconstituted to 12.5% DM and fed at 12% of calf body weight, adjusted weekly. Water was offered ad libitum but no starter was fed. Three calves per treatment were harvested weekly to sample digesta from the reticulo-rumen, abomasum, jejunum, proximal colon, and distal colon, and to determine length and mass of GIT components. Psyllium in milk replacer increased the proportion of butyrate in reticulo-rumen contents from 2.4 to 3.2% of total but did not affect total VFA concentrations. Total VFA concentrations were very low in the jejunum but psyllium tended to increase total VFA, acetate, and valerate concentrations; valerate accounted for 15.9 and 16.7% of total VFA (molar basis) for control and psyllium calves, respectively. Psyllium increased total VFA concentrations in the proximal and distal colon by 104.4 and 45.6%, respectively, but had little effect on the profile of VFA. Psyllium in milk replacer increased populations of bifidobacteria (from 9.7 to 10.3 log(10) cfu/g of DM) and lactobacilli (from 8.2 to 9.4 log(10) cfu/g of DM) in the reticulo-rumen, but did not affect populations in jejunum or colon. Calves fed psyllium had 12.0% greater total GIT mass and 9.4% greater GIT as a percentage of body weight. Psyllium tended to increase mass of the reticulo-rumen and significantly increased mass of duodenum (34.2%), jejunum (14.5%), and colon (14.6%). Density of intestinal tissues from calves fed psyllium-supplemented milk replacer was 25.9% greater in the jejunum and 25.3% greater in the ileum, and tended to be greater in duodenum and colon than tissue from control calves. Supplementation of psyllium to milk replacer increased fermentation in the colon, mass of the total GIT, and populations of bifidobacteria and lactobacilli in the reticulo-rumen.

Inclusion of psyllium in milk replacer for neonatal calves. 1. Effects on growth, digesta viscosity, rate of passage, nutrient digestibilities, and metabolites in blood.

Based on research in other species, inclusion of psyllium in milk replacer might improve nutrient utilization and gastrointestinal function in neonatal calves. Male Holstein calves were fed a milk replacer (22% crude protein, 20% fat) either without or with psyllium (1.1% of dry matter) from 2 d through 28 d of age. Milk replacer was reconstituted to 12.5% dry matter (DM) and fed at 12% of calf body weight (BW), adjusted weekly. Water was offered ad libitum but no starter was fed. Three calves per treatment were harvested weekly to sample digesta from the rumen, abomasum, jejunum, proximal colon, and distal colon. Mean daily intakes of water, DM, crude protein, and metabolizable energy did not differ between treatments. Average daily gain of BW did not differ between treatments. Digesta from the abomasum and colon of calves fed psyllium was more viscous than digesta from control calves. Mean retention time of digesta in the total digestive tract tended to be greater for calves supplemented with psyllium (9.7 vs. 8.4h). Feces and digesta from the proximal and distal colon of calves fed psyllium had lower DM content than feces and digesta from control calves. Total-tract apparent digestibility of DM (92.8 vs. 94.1%) was lower for psyllium-fed calves, likely as an effect of the addition of the more poorly digestible psyllium; digestibilities of energy and ash also tended to be lower. The prefeeding plasma glucose concentration (10h after previous feeding) tended to be greater for psyllium-fed calves but concentrations of nonesterified fatty acids, beta-hydroxybutyrate, cholesterol, urea N, and total protein did not differ between treatments. Blood components did not differ between treatments at 2h postfeeding. Inclusion of psyllium in the milk replacer of neonatal calves increased digesta viscosity and slowed passage of digesta through the gastrointestinal tract.