The study evaluated the long-term influence of feeding ground
barley treated with lactic acid (LA) alone or with LA and heat on
performance, energy and protein balance in dairy cows. Thirty
cows were fed three diets differing in the treatment of barley
grain, either unprocessed ground barley (Control), ground barley
steeped in 1% LA at room temperature (LA-treated barley) or
ground barley steeped in 1% LA with an additional heating at
55°C (LAH-treated barley). Cows were studied from week 3 to 17
post-partum. Dry matter intake (DMI), milk yield and composition
and body weight (BW) were measured daily. Estimated energy
and protein balances were calculated and blood samples were
collected three times during the experiment and analysed for
common metabolites of energy and lipid metabolism.
Digestibility of different treated barley and other dietary ingredients
was investigated in vivo using four wethers. The treatment of
barley with LA and LAH increased the digestibility of organic
matter (OM) by approximately 5% and the content of metabolisable
energy by 0.5–0.6 MJ/kg DM. Data showed no effect of
feeding diets containing LA- or LAH-treated barley at 39% of
DM on overall DMI, BW, BW change, milk production and composition
and on the blood variables studied. Diet influenced the
estimated balances of net energy of lactation (p < 0.01) and the
content of utilisable protein at the duodenum (p = 0.07) with
cows fed the diet with LA-treated barley showing improved balances.
In conclusion, feeding diets containing LA- or LAH-treated
barley had no influence on performance, milk composition and
blood metabolites, but LA treatment without heat seems to
improve the energy balance of cows.