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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #324703
Title: Feeding strategy and pasture quality relative to nutrient requirements of dairy cows in the northeastern U.S

Author
item HAFLA, AIMEE - Agri-King, Inc
item Soder, Kathy
item BRITO, ANDRE - University Of New Hampshire
item KERSBERGEN, RICHARD - University Of Maine
item BENSON, FAY - Cornell University
item DARBY, HEATHER - University Of Vermont
item Rubano, Melissa

Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2016
Publication Date: 8/1/2016
Citation: Hafla, A.N., Soder, K.J., Brito, A., Kersbergen, R., Benson, F., Darby, H., Rubano, M.D. 2016. Feeding strategy and pasture quality relative to nutrient requirements of dairy cows in the northeastern U.S. Professional Animal Scientist. 32:523-530.

Interpretive Summary: Little research has evaluated the nutritional content of pastures relative to nutrient needs of grazing dairy cows. We conducted a study to determine how frequently pastures in the northeastern U.S. met nutrient requirements of lactating dairy cows and to describe a sample of the feeding strategies accompanying grazing on these farms. Nutritional quality of pastures was generally high, with energy as the most limiting dietary component, which can be corrected with energy supplementation. High quality pasture and diverse supplementation strategies allow farmers to use resources such as pasture and homegrown forages and grains to meet goals of milk production for their farm. Previous research has confirmed that some degree of supplementation of grazing dairy cows will result in a profitable increase in milk production, however it is important to recognize that markets currently exist that pay premiums for value-added milk products (such as grass-fed milk) which may negate the economic benefits of supplementation.

Technical Abstract: Pasture samples (n = 380) collected during the grazing season on 14 dairy farms from 2012 to 2014 were analyzed for nutritional composition to determine the frequency of pasture samples that met minimum net energy for lactation (NEl), crude protein (CP), and macro-mineral requirements according to the National Research Council (NRC, 2001) model for Holstein and Jersey cows (milk production of 25 kg/d). The Large Ruminant Nutrition System model was used to evaluate feeding strategies that accompanied grazing. If pasture was the only dietary component, energy was limiting, as 36 and 86% of pastures failed to meet minimum NEl requirements for Holstein and Jersey cows, respectively. On average, pasture samples lacking in energy contained only 88% of NEl required for either breed. Nine and 21% of pastures did not meet the minimum CP requirements, while calcium (Ca), phosphorus (P), and sulfur (S) did not meet minimum NRC requirements in 31 and 22, 19 and 26, and 11 and 7% of samples, for Holstein and Jersey cows, respectively. Magnesium and potassium (K) in pastures sampled were 56 and 1017% in excess of dietary requirements, respectively. Farms were categorized as having low, moderate, or high conserved feed input (LC, MC, HC). Milk production was numerically lowest for LC farms, (16.8 kg/d) and greater for MC and HC farms (20.0 and 21.3 kg/d, respectively). Average dry matter intake (DMI) from pasture was 90%, 46%, and 26% for LC, MC, and HC farms, respectively. Overall, forage quality of pastures was high. Varying feeding strategies allow farmers to use resources such as pasture, homegrown forages, and concentrates to meet individual production goals.