Effects of chop length of alfalfa and corn silage on milk production and rumen fermentation of dairy cows
| Autor: | S.K. Bhandari, Jan C. Plaizier, K.M. Wittenberg, K.H. Ominski |
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| Rok vydání: | 2007 |
| Předmět: |
Rumen
Silage Total mixed ration Biology Zea mays 03 medical and health sciences Eating Fodder Latin square Genetics Animals Lactation Dry matter Food science Particle Size Dairy cattle 030304 developmental biology 2. Zero hunger 0303 health sciences 0402 animal and dairy science food and beverages 04 agricultural and veterinary sciences 040201 dairy & animal science Animal Feed Gastrointestinal Contents Diet Neutral Detergent Fiber Dairying Milk Fermentation Animal Science and Zoology Cattle Female Blood Chemical Analysis Food Science Medicago sativa |
| Zdroj: | Journal of dairy science. 90(5) |
| ISSN: | 1525-3198 |
| Popis: | Effects of chop length (shorter = 10 mm or longer = 19 mm) of alfalfa silage and corn silage were determined in 16 midlactation Holstein cows using a 4 x 4 Latin square design with a 2 x 2 arrangement of treatments. Experimental periods were 21 d long and consisted of 14 d of adaptation and 7 d of sampling. Cows received total mixed ration containing (dry matter basis) 44.0% barley grain-based energy supplement, 12.6% protein supplement, and 21.7% longer chop or shorter chop alfalfa silage and 21.7% longer chop or shorter chop corn silage. Reducing the chop length of alfalfa silage and corn silage reduced the average geometric particle length from 14.4 to 11.0 mm and from 14.2 to 10.4 mm, respectively. Reducing the chop length of both silages reduced the proportion of the diets retained by the 8- and 19-mm screen of the Penn State Particle Separator from 55.0 to 46.0% of dry matter. Reducing the alfalfa chop length increased total rumen volatile fatty acids at 4 to 5 h after feeding but did not affect rumen pH at 4 to 5 h after feeding, feed intake, and milk production. Reducing the corn silage chop length increased dry matter intake from 22.3 to 23.2 kg/d, increased rumen pH at 4 to 5 h after feeding from 6.12 to 6.20, but did not alter rumen volatile fatty acids at 4 to 5 h after feeding or milk production. Daily milk yield, milk fat percentage, and milk protein percentage averaged 38.2 kg/d, 2.62%, and 3.29%, respectively, across all diets. The low milk fat percentages suggest that all diets induced subacute ruminal acidosis (SARA), whereas the rumen pH did not indicate SARA. This discrepancy could be due to a difference in the time of rumen pH measurement and the time of the lowest rumen pH. Hence, the pH data need to be interpreted with caution. Diets could have induced SARA, because for all experimental diets the content of forage neutral detergent fiber was lower than recommended for barley grain-based diets. |
| Databáze: | OpenAIRE |
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