Survey of barley grain physical processing methods in Holstein dairy cow's ration

Abstract

Barley is one of the most commonly used food grains in the diet of dairy and beef cattle. Since barley endosperm is enclosed by a sheath highly resistant to microbe degradation in Rumen, it is necessary to process dry barley grain for optimal use by dairy and beef cattle. In order to compare different methods of barley grain’s physical processing in the diet of dairy cattle and its effect on milk production, 9 Holstein cattle (in the first, second and third birth) that were at a distance of 10 ± 65 days after delivery, were selected . This experiment was performed was in a randomized complete block design with three replications (parity), four treatments (processing method) and three cattle per block. Barely grains were put in diets numbered from 1 to four, respectively through the following ways:(1) Hammer mill (with a sieve 1 mm), (2) dry roll by Index processing 73%, (3) Fusion (a mixture of first way and second way ) (4) rolling along with steam by processing index 65% of processing percent. The data included amount of milk, percent of fat and dry matter use for each of the three milking. Average milk production of cattle that were fed by diets 1, 2, 3 and 4 were respectively 33.60c, 34.23b, and 34.38b and 34.60a kg per day. Also the averages of fat percent were equal to 3.02a, 2.70c, and 2.73c and 2.84b. In both groups, the mean difference was significant at one percent level. According to the findings and production purpose (the increase of milk production) rolling machine under steam can be proposed, however, considering high cost of the device, it can be justified for large units. For small farms, dry roll with less processing index is recommended.