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Fourteen organic dairy farms in the northeastern United States were used to evaluate (1) seasonal variation in bioactive milk fatty acid (FA) profile from 2012 to 2015 and (2) supplementation of ground whole flaxseed (GFLX) to maintain elevated concentrations of bioactive milk FA during the nongrazing season. During regular farm visits, milk, feed, and pasture samples were collected, and diet composition, milk yield, and milk composition were recorded. During winters of 2013 to 2014 and 2014 to 2015, 9 farms supplemented GFLX at 6% of diet DM to half of each herd (n = 238 cows per treatment). Milk samples were collected and pooled by treatment (GFLX or control). Data were analyzed using the MIXED procedure of SAS. A significant month × year interaction (P 0.15) milk yield or concentrations of milk fat or protein; however, BCS tended (P = 0.08) to be greater for GFLX cows. Compared with the control diet, GFLX decreased (P

Pasture samples (n = 380) collected during the grazing season on 14 dairy farms (2012 to 2014) were analyzed for nutritional composition. The MIXED procedure of SAS was used to test effect of year, month, and farm. Frequency analysis was used to determine the proportion of pasture samples that met minimum NEl, CP, and macro mineral requirements of lactating Holstein and Jersey cows (25 kg of milk/d; NRC, 2001). The Large Ruminant Nutrition System model was used to evaluate feeding strategies that accompanied grazing. Each year, forage quality declined with the advancing grazing season (CP, NEl, P

Molasses is used by some producers with grazing dairy cows to replace greater-costing corn. However, anecdotal results are mixed, and little research exists evaluating the effects of molasses fed to grazing dairy cows as the sole supplement. This study evaluated the effect of rate of molasses supplementation and forage nutritive value (NV) on ruminal fermentation in continuous-culture fermentors. We used a 4 × 4 Latin-square design with treatments in a 2 × 2 factorial arrangement, and the treatments were 1) good NV pasture (63 g DM/d; 26.8% CP, 35.9% NDF) plus blackstrap molasses at 10% of total DM fed (7 g DM/d; G10); 2) good NV pasture (66.5 g DM/d) plus molasses at 5% of total DM fed (3.5 g DM/d; G5); 3) poor NV pasture [relative to good NV pasture (20.4% CP, 45.3% NDF); 63 g DM/d] plus molasses at 10% of total DM fed (7 g DM/d; P10); and 4) poor NV pasture (66.5 g DM/d) plus molasses at 5% of total DM fed (3.5 g DM/d; P5). Apparent OM and ADF digestibilities and true DM and OM digestibilities, mean ruminal pH, and concentrations of total and individual VFA were greater (P 0.10) by forage NV or molasses supplementation rate. No significant interaction between forage NV and molasses supplementation rate relative to ruminal fermentation was detected. Molasses may need to be evaluated on a case-bycase basis to determine feasibility as an energy substitute for grazing dairy cows.

Although molasses is being used by dairy farmers, particularly certified organic dairies, as a lower cost energy alternative to corn, little research currently exists evaluating the effects of molasses as the sole supplement on the ruminal fermentation of grazing dairy cows. This study evaluated the effects of pasture supplementation with molasses, corn meal, or a combination of molasses and corn meal, on ruminal nutrient digestibility and bacterial N synthesis in continuous culture fermenters. Experimental treatments were 1) orchardgrass (Dactylis glomerata L.) pasture only (control; 70 g DM/d); 2) molasses plus orchardgrass pasture (MOL; 3.5 g DM/d of molasses plus 66.5 g DM/d of pasture); 3) corn meal plus orchardgrass pasture (CM; 4.9 g DM/d of corn meal plus 65.1 g DM/d of pasture); and 4) molasses plus corn meal plus orchardgrass pasture (MOL + CM; 3.5 g DM/d of molasses plus 4.9 g DM/d of corn meal plus 61.6 g DM/d of pasture). Treatment did not affect (P > 0.05) apparent DM, OM, and NDF digestibility values; true DM and OM digestibility values; molar proportions of VFA; or acetate-to-propionate ratio. Mean ruminal pH tended (P = 0.071) to be greater for MOL. Maximum ruminal pH was greatest (P 0.05). At low levels of inclusion, molasses showed results similar to corn meal in improving ruminal fermentation and N utilization, with both supplements showing only minimal improvement compared with a pasture-only diet.