Increasing Nutrient Production on Dairy Farms By Less Frequent Harvesting of Late Maturing Grass Varieties.

Modern dairy operations often depend on significant amounts of purchased feed to meet nutritional needs of high producing cows, but these feed imports add economic and often environmental burdens, especially if land is limited. In south-coastal BC and nearby WA state dairy farmers often purchase over 40% of their feedstuffs which may include straw for supplemental fiber.  The experiment reported here is part of a study to improve quantity and quality of home grown forage production to reduce nutrient imports. The concept for increasing feed is: 1. increasing grass production by delaying harvesting and using late maturing varieties to mitigate decline in nutritional quality; 2. using land spared by additional grass yield for higher yielding silage corn plus high protein winter cover crops. This study compares early and late varieties of both tall fescue (TF) and orchardgrass (OG) under conventional (5-cut) and reduced (3-cut) harvesting frequencies over two years. In 2014, all varieties yielded about 1.5 t ha^-1 more under 3-cuts than 5-cuts, recovered about 25 kg ha^-1 more N, and had 0.5-1.0% less crude protein (CP).  The early TF variety yielded slightly more than the late but the late OG yield more than the early.  In 2015, the 3-cut system increased yield by about 5 and 3.5 t ha^-1, N uptake by 65 and 41 kg ha^-1, but CP was reduced by 2.9 and 2.2% for TF and OG, respectively. Compared to conventional (5-cut, early OG), the optimum treatment (3-cut late TF) had 3.2 t ha^-1 more yield, 36 kg ha^-1 more N uptake and 1.2% lower CP in 2014, and 4 t ha^-1 more yield, 58 kg ha^-1 more N uptake and 2.1% less CP in 2015. Complete feed analyses will be conducted and results modeled to determine if this strategy will enhance farm feed sufficiency.