Effect of wheat middlings-based total mixed ration on milk production and composition responses of lactating dairy ewes

Abstract

The effect of feeding pelleted total mixed ration (TMR) containing wheat middlings (WM) from durum wheat (Triticum durum Desf. cv. Appulo) as a corn grain substitute on milk yield and composition performance was measured in Comisana×Leccese crossbred lactating ewes. Forty ewes were divided into 2 equal groups and fed 1 of the 2 experimental diets for 18 wk. The control diet contained 255 g of corn/kg of dry matter (DM) as the main starch source, whereas the experimental diet contained 500 g of WM/kg of DM. To evaluate the in vivo digestibility of pelleted TMR, 4 adult rams were placed in metabolic cages and their individual feces and urine were collected. In the performance trial, ewe milk yield was recorded daily and individual milk samples were analyzed weekly for milk composition and to determine milk renneting parameters. The ewes fed both diets showed similar DM, crude protein, and neutral detergent fiber intakes. Digestibility of DM, organic matter, and crude protein of the 2 TMR was similar, but neutral detergent fiber digestibility was higher in the WM diet. In the milking trial, the WM diet increased milk fat percentage and yield but had no effect on milk yield, protein, lactose, and clotting properties compared with the control diet. Our findings indicate that WM can be fed to lactating ewes as an alternative to more traditional concentrate sources such as corn. Feeding 50% of WM in a lactation diet supported milking performance in a manner similar a corn-based diet. Moreover, the results may be applied in countries where corn cultivation is adversely affected by the high cost of production.