Performance of lactating dairy cows fed alfalfa or red clover silage as the sole forage

Three Latin square trials, with 20 (two trials) or 24 (one trial) multiparous lactating Holstein cows (four in each trial with ruminal cannulae), compared the feeding value of red clover and alfalfa silages harvested over 3 yr. Overall, the forages contained similar amounts of neutral detergent fiber and acid detergent fiber; however, red clover silage contained more hemicellulose, less ash and crude protein (CP), and only 67% as much nonprotein N, as a proportion of total N, as did alfalfa silage. Diets were formulated with equal dry matter (DM) from alfalfa or red clover silage and contained on average 65% forage, 33 or 30% ground high moisture ear corn, and 0 or 3% low soluble fishmeal (DM basis). Diets fed in the Latin squares contained (mean dietary CP): 1) alfalfa (17.8% CP); 2) red clover (15.1% CP); 3) alfalfa plus fishmeal (19.6% CP); and 4) red clover plus fishmeal (16.9% CP). Although performance varied somewhat among trials, overall statistical analysis showed that replacing alfalfa with red clover reduced yields of milk, fat-corrected milk, fat, protein, lactose, and SNF; these effects were related to the 1.2 kg/d lower DM intake for cows fed red clover. Replacing alfalfa with red clover improved body weight gain and reduced concentrations of milk and blood urea and ruminal NH3. Apparent digestibility of DM, organic matter, neutral detergent fiber, acid detergent fiber, and hemicellulose all were greater when red clover was fed. There were no significant forage x fishmeal interactions for DM intake and yield of milk and milk components, indicating that supplementation with rumen undegradable protein gave similar increases in production on both forages. Net energy of lactation (NEL), estimated from maintenance, mean milk yield, and body weight change, in alfalfa and red clover silage were, respectively, 1.25 and 1.38 Mcal NEL/kg of DM, indicating 10% greater NEL in red clover.