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Response of lactating dairy cows to degree of steam‐flaked barley grain in low‐forage diets
Author(s) -
Safaei Kh.,
Ghorbani G. R.,
Alikhani M.,
Sadeghi Sefidmazgi A.,
Yang W. Z.
Publication year - 2017
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1111/jpn.12565
Subject(s) - forage , zoology , degree (music) , lactation , dairy cattle , biology , agronomy , food science , pregnancy , genetics , physics , acoustics
Summary This study was conducted to investigate the effects of processing method (grinding vs. steam flaking) and increasing densities of steam‐flaked barley grain on dry matter intake ( DMI ), rumen pH and fermentation characteristics, digestibility of dry matter in the total digestive tract ( DDTT ), and milk production of dairy cows. Eight multiparous mid‐lactation Holstein cows averaging 103 ± 24 DIM , 44.5 ± 4.7 kg milk/day and weighing 611 ± 43 kg at the start of the experiment were used in a replicated 4 × 4 Latin square design with 21‐day periods. Cows were fed diets consisting of ( DM basis) 23.8% corn silage, 13.5% chopped alfalfa hay and 62.7% concentrate. The dietary treatments were either ground barley ( GB ) using a hammer mill or steam‐flaked barley ( SFB ) – varying density at 390, 340 or 290 g/l. Processing method ( GB vs. SFB ) did not affect DMI (23.6 kg/day on average), DDTT (71.0% on average), milk yield (43.4 kg/day on average), milk components, rumen pH and molar proportions of acetate, propionate, butyrate and sorting activity. Ruminal isovalerate concentration tended (p = 0.06) to be higher for cows fed GB than those fed SFB ‐based diets. Decreasing the density of SFB from 390, 340 to 290 g/l tended to linearly increase DMI (p = 0.09), decrease total solids percentage of milk (p = 0.10) and linearly decreased milk urea nitrogen (12.8, 12.4 and 12.1 mg/dl; p = 0.04); also, the sorting index ( SI ) of the particles retained on the 19.0‐mm sieve without affecting the SI of the particles retained on 8.0‐mm, 1.18‐mm or passed through 1.18‐mm sieve (p = 0.05). These results indicated the limited effects of processing method (grinding vs. steam flaking) and densities of SFB (390, 290 or 290 g/l) on cows’ performance and feed utilization for dairy cows fed low‐forage diets. Therefore, both processing methods could be recommended under current feeding conditions of dairy cows.