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Effects of Silage Fermentation and Post‐ruminal Casein Supplementation in Lactating Dairy Cows: 1—Diet Digestion and Milk Production
Author(s) -
Huhtanen Pekka J,
Miettinen Harri O,
Toivonen Vesa F J
Publication year - 1997
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199708)74:4<450::aid-jsfa818>3.0.co;2-w
Subject(s) - silage , dry matter , casein , propionate , microbial inoculant , food science , fermentation , lactic acid , chemistry , rumen , zoology , formic acid , digestion (alchemy) , biology , biochemistry , bacteria , chromatography , genetics
Two silages were prepared from the first‐cut sward of timothy‐meadow fescue and wilted to a dry matter (DM) content of 300 g kg ‐1 . One was ensiled with the addition of a formic‐acid‐based additive (4 litres formic acid (FA) per tonne) and the other with the addition of a bacterial inoculant (LAB) at a rate of 5×10 6 colony forming units g ‐1 . Both silages were well preserved, but the extent of fermentation was greater in LAB‐silage than in FA‐silage as indicated by a lower concentration of water soluble carbohydrates (68 vs 177 g kg ‐1 DM) and a higher concentration of lactic acid (147 vs 32 g kg ‐1 DM). Four Ayrshire cows were used in a 4×4 Latin square experiment with 21‐day periods to study the effects of silage fermentation and postruminal casein supplementation on silage intake, nutrient supply and milk production. The four treatments were FA‐silage without casein (FA‐0), LAB‐silage without casein (LAB‐0), FA‐silage with casein (FA‐C) and LAB‐silage with casein (LAB‐C). Both silages were given ad libitum with 8 kg day ‐1 of barley without or with 400 g day ‐1 of casein infused into the duodenum. Organic matter digestibility was lower (0·723 vs 0·753; P <0·01) for FA‐silage than for LAB‐silage. Cows offered FA‐silage had a higher molar proportion of acetate and a lower proportion of propionate in ruminal fluid than cows offered LAB‐silage. Microbial protein synthesis estimated from the output of purine derivatives in urine was greater (288 vs 260 g N day ‐1 ; P <0·05) for cows given FA‐silage compared with LAB‐silage. Feeding LAB‐treated silage tended ( P <0·10) to decrease silage DM intake compared with FA‐treated silage (10·61 vs 11·77 kg DM day ‐1 ). Silage composition did not affect significantly milk yield or milk composition. Casein infusion increased milk yield (25·1 vs 27·1 kg day ‐1 ; P <0·05), milk protein content (32·4 vs 33·8 g kg ‐1 ; P <0·05) and protein yield (808 vs 905 g day ‐1 ; P <0·01). The responses were similar for both silages. © 1997 SCI.