Growth performance, ruminal fermentation profiles, and carcass characteristics of beef steers grazing tall fescue without or with nitrogen fertilization1

The effects of organic grass and grass-birdsfoot trefoil pastures on Jersey heifer development: Herbage characteristics affecting intake

Low dietary energy and decreased intake of herbage have been attributed to the reduced performance of grazing dairy cattle. We hypothesized that grasses with inherently greater energy would interact in a complementary way with condensed tannins (CT) in birdsfoot trefoil to increase herbage intake by grazing dairy heifers. Eight pasture treatments comprising high-sugar perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus riparius Rehmann), and tall fescue [Schendonorus arundinaceus (Schreb.) Dumort] were established in Lewiston, Utah as monocultures and binary mixtures with birdsfoot trefoil (Lotus corniculatus L.; BFT). Pasture treatments were rotationally stocked by Jersey heifers for 105 d in 2017 and 2018, and herbage samples were collected pre- and postgrazing for each 7-d grazing period and analyzed for herbage mass, nutritive value, and apparent herbage intake. We observed differences among pasture treatments in herbage quantity and nutritive value, as well as differences in herbage intake by grazing Jersey heifers. On average, grass-BFT mixtures had greater herbage intake than grass monocultures, and every grass-BFT treatment individually had greater herbage intake than their respective grass monocultures. Using multivariate analyses, we determined that approximately 50% of the variation in herbage intake was due to nutritive and physical herbage characteristics, with the most explanatory being characteristics related to fiber and energy, followed by those related to the percent of BFT in the herbage. Grass monocultures exhibited a range of inherent dietary energy, but there was indication that an imbalance of energy to crude protein (e.g., protein deficient) reduced intake of grass monocultures. Moreover, there was some evidence of a complementary effect between increased dietary energy and CT; however, low CT levels made it impossible to determine the effect of CT on herbage intake per se. This study confirmed that chemical and physical characteristics inherent to different pasture species have a large effect on herbage intake by grazing cattle. Pastures planted to binary mixtures of nutritious grasses and birdsfoot trefoil increase herbage intake of temperate pastures by grazing Jersey heifers.

Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system

Berthiaume, R., Lafrenière, C., Girard, C., Campbell, C. P., Pivotto, L. M. and Mandell, I. B. 2015. Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system. Can. J. Anim. Sci. 95: 173–187. Forty weaned, crossbred beef calves (predominantly Angus and Simmental) were forage-finished using all-silage diets (red clover–timothy versus tall fescue) to examine forage species’ effects on growth performance, carcass traits, meat quality, and nutrient composition. Weaned calves (257 d of age) were forage-finished using red clover–timothy or tall fescue silage and harvested at approximately 1 yr of age. During carcass processing, one side from each carcass was covered with a polyliner to examine if reducing rates of chilling could compensate for limited fat cover expected from low dietary energy contents fed, and limited time on feed. Longissimus thoracis, semimembranosus, and semitendinosus steaks were aged 10, 14, and 21 d to examine effects on Warner–Bratzler shear force values while fatty acid and vitamin B12 composition were determined on 10-d-aged steaks. Average daily gain, feed efficiency, hot carcass weights, and longissimus muscle area were greater (P<0.03) when cattle were fed red clover–timothy versus tall fescue silage, most likely due to the higher protein content of red clover–timothy silage. Shear force was greater (P<0.002) in steaks from all muscles evaluated from cattle fed tall fescue versus red clover–timothy silage. In comparison to 10-d-aged steaks, 14 d of ageing were needed to reduce (P<0.001) shear force for longissimus steaks, while 21 d of ageing were needed to reduce (P<0.001) shear force for semitendinosus steaks. Use of a polyliner decreased (P=0.0001) the rate of temperature decline at selected carcass sites, but did not reduce shear force values. The percent of n-3 fatty acids and polyunsaturated fatty acid/saturated fatty acid ratio were greater (P<0.04) in longissimus from cattle fed red clover–timothy versus feeding tall fescue silage. Feeding red clover–timothy silage improved growth performance, carcass, shear force, and fatty acid composition traits versus feeding tall fescue silage.