Resumen:
This experiment studied effects of a mixture of exogenous enzymes
(ZADO®) from anaerobic bacteria on ruminal fermentation, feed
intake, digestibility, as well as milk production and composition
in cows fed total mixed rations (TMRs; 0.7 corn silage and 0.3 of a
concentrate mixture). Twenty lactating multiparous Brown Swiss
cows (500±12.4 kg live weight) were randomly assigned into two
experimental groups of 10 immediately after calving and fed a
TMR with or without (CTRL) addition of 40 g/cow/d of enzymes for
12 weeks. Addition of enzymes increased (P<0.05) rumen microbial
N synthesis. Intake of dry matter (DM) and organic matter
(OM) was positively influenced (P<0.05) by supplementation, and
digestibility of all nutrients was higher (P<0.05) in the total tract
of supplemented cows, although the magnitude of the improvement
varied among nutrients, with the highest improvement in
aNDFom and ADFom (418–584 and 401–532 g/kg respectively; P<0.05) than the other nutrients. Supplementation of enzymes also
increased (P<0.05) rumen ammonia N and total short chain fatty
acid (SCFA) concentrations, and individual SCFA proportions were
also altered with an increase in acetate (61.0–64.8 mol/100 mol;
P=0.05) before feeding, and acetate and propionate increased
3 h post-feeding (60.0–64.0 and 18.3–20.8 mol/100 mol respectively;
P<0.05). Milk and milk protein production was higher
(12.8–15.7 and 0.45–0.57 kg/d respectively; P<0.05) forcowsfed the
ZADO® supplemented diet. This exogenous enzyme product, supplemented
daily to the TMR of cows in early lactation, increased
milk production due to positive effects on nutrient intake and
digestibility, extent of ruminal fermentation and microbial protein
synthesis.
