|KNOWLTON, KATHARINE - Virginia Polytechnic Institution & State University|
|WILKERSON, VICTOR - Land O' Lakes Purina Feed, Llc|
|CASPER, DAVID - Agri-King, Inc|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2009
Publication Date: 12/22/2009
Citation: Knowlton, K.F., Wilkerson, V.A., Casper, D.P., Mertens, D.R. 2009. Manure Nutrient Excretion by Jersey and Holstein Cows. Journal of Dairy Science. 93(1):407-412.
Interpretive Summary: Nutrient management planning is a priority for livestock producers. The revised federal regulations for concentrated animal feeding operations (CAFO) and the CAFO permitting programs of many states define CAFOs as a specified number of cows, making no distinction among breeds or cow size. There is an abundance of information on manure nutrient excretion from lactating Holstein cows, but data quantifying nutrient excretion by Jersey cows are scarce. For example, the American Society of Agricultural and Biological Engineers (ASABE) used only Holstein data to derive equations to predict manure and nutrient excretion for dairy cows. Because Holstein cows often weigh 1,300 to 1,500 lb compared to Jerseys, which weigh 800 to 1,000 lb, the effect of breed on manure and nutrient excretion may have significant nutrient management implications. We used manure nutrient excretion by 8 Holstein and 8 Jersey cows to quantify differences due to breed. Total manure excretion was lower in Jersey cows than in Holstein cows, with reductions generally proportional to changes in feed intake. The smaller Jersey cows ate less and produced less manure than the larger Holstein cows. The ASABE tabular values for daily manure excretion derived from Holstein cows are not appropriate for Jersey cows, but the manure solids prediction equations which include animal and dietary factors, such as level of feed intake, may be appropriately applied to Jersey cows. We concluded that accounting for breed differences in manure excretion will result in more effective nutrient management planning on dairy farms having Jersey cows.
Technical Abstract: The objective was to evaluate feces, urine, and nitrogen (N) excretion by Jersey and Holstein cows. Sixteen multiparous cows (n=8 per breed) were fed two experimental rations at calving in a switchback experimental design. Diets were 50% forage and based on corn meal (control) or whole cottonseed. Half the cows in each breed started on the control diet and half started on the whole cottonseed diet. Cows were switched to the other diet at 60 DIM and back to their original diet at 165 DIM. Pairs of cows were moved into open circuit respiration chambers on day 49, 154, and 271 of lactation for 7-d measurement periods. While in the chambers, total collection of feed refusals, milk, recovered hair, feces and urine was conducted. No effect of the interaction of diet and breed was observed for measures of nutrient digestibility and manure excretion. Total daily manure excretion was lower in Jersey cows than in Holstein cows, with reductions generally proportional to changes in feed intake. Jersey cows consumed 29% less feed, and excreted 33% less wet feces and 28% less urine then Holstein cows. Intake, fecal, and urinary N were reduced by 29, 33, and 24% in Jersey cows as compared to Holstein cows. The effect of breed on manure and nutrient excretion has significant nutrient management implications. The ASAE equations under-predicted observed values for all manure measures evaluated (urine, manure solids, N, wet manure) and breed bias was observed in equations predicting excretion of urine, N and wet manure. Although these equations include animal and dietary factors, intercepts of regression of observed values on predicted differed between Holstein and Jerseys for those three measures. No breed bias was observed in the prediction of manure solids excretion, however, making that equation equally appropriate for Jerseys and Holsteins. The effect of breed on manure and nutrient excretion has significant nutrient management implications.