Title: Case study: dairies utilizing ultra-high stocking density grazing in Pennsylvania and New York Authors
Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2014
Publication Date: June 1, 2014
Citation: Orr, A.N., Soder, K.J., Hautau, M., Rubano, M.D., Moyer, B., Stout, R.C. 2014. Case study: dairies utilizing ultra-high stocking density grazing in Pennsylvania and New York. Professional Animal Scientist. 30:366-374. Interpretive Summary: Ultra-high stocking density grazing is characterized by grazing plants that are more mature, with greater stocking densities (units of animal liveweight/units of area), and providing forage with longer periods of rest between grazing rotations compared to management intensive grazing systems. Many of the current recommendations for ultra-high stocking density grazing refer to beef cattle in rangeland environments; however some grazing dairy farmers in the northeastern U.S. have implemented components of this grazing management system. Based on observations of this study, grazing dairies in PA and NY have taken a modified approach to ultra-high stocking density grazing definitions by grazing forages slightly more mature than recommended in management intensive grazing systems and slowing grazing rotations to allow plants to mature. However, forages were not as mature and grazing rotations were not as long as indicated by farmers utilizing ultra-high stocking density grazing with beef cattle. Longer grazing rotations may increase available forage, however farmers must be conscious of maintaining forage quality to meet the high nutritional requirements of lactating dairy cows.
Technical Abstract: Ultra-high stocking density (UHSD) grazing has gained interest in the forage industry. Proponents of UHSD emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 560,425 kg ha**-1 of beef cattle on small paddocks with rest periods of up to 125 days. However, it is unclear if this management technique is appropriate for Northeastern dairies. A case study was conducted to characterize management practices and forage and soil quality on grazing dairy farms utilizing self-described UHSD grazing. Data collected on 4 dairy farms in PA and NY included: pasture and soil nutrient analyses, stocking density, botanical composition, and pasture stratification. Herds were mixed breed with milk yields ranging from 11.9 to 17.7 kg day**-1 per cow. Stocking density ranged from 49,421 to 377,912 kg ha**-1 with an average of 39 days of forage rest. Forage consumed was 46 and 45% of total available in 2012 and 2013, respectively. Cows consumed 75% of forage from stratification layers 33 cm and higher and 49% from layers below 33 cm. Forage CP, NDF, and NEL averaged 24%, 44.7% and 1.43 Mcal kg**-1, respectively. The increase in forage quality observed from Jun. to Sep. 2012 was likely a result of forage being less mature at each successive grazing. Soil mineral content and pH were within recommended levels for all farms. Grazing dairies in the Northeast have taken a modified approach to the UHSD definition by grazing forages more mature than traditionally recommended in management-intensive grazing systems and allowing longer periods of forage rest.