Efficacy of recycled sand or organic solids as bedding sources for lactating cows housed in freestalls

Authors: ESSER, NANCY - University Of Wisconsin; SU, H. - China Agricultural University; Coblentz, Wayne; AKINS, MATTHEW - University Of Wisconsin; KIEKE, BURNEY - Marshfield Clinic Research; Martin, Neal; Borchardt, Mark; Jokela, William

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2019
Publication Date: 6/14/2019
Citation: Esser, N.M., Su, H., Coblentz, W.K., Akins, M.S., Kieke, B.A., Martin, N.P., Borchardt, M.A., Jokela, W.E. 2019. Efficacy of recycled sand or organic solids as bedding sources for lactating cows housed in freestalls. Journal of Dairy Science. 102(7):6682-6698. https://doi.org/10.3168/jds.2018-15851.
DOI: https://doi.org/10.3168/jds.2018-15851

Interpretive Summary: Currently, multiple choices exist for the resting surface and bedding type for dairy herds housed in freestalls throughout the United States. Sand bedding is usually considered the bedding of choice within freestalls, but the costs and burdens of handling sand-ladden manure often cause dairy producers to seek alternatives. One of these alternatives is to use organic solids reclaimed from manure separation systems; within this context, organic solids have no cost and are available in near limitless supply, but there are concerns about increased incidence of mammary infection. Our objective was to compare bedding systems with respect to manure composition, cow welfare and hygiene assessments, measures of milk production and quality, and incidence of mastitis during a 3-yr trial with primarily first-lactation Holstein cows housed in a freestall-barn containing 4 identical quadrants (pens) with 32 freestalls/pens. Bedding systems evaluated included deep-bedded organic manure solids, shallow-bedded manure solids spread over mattresses, and deep-bedded recycled or new sand. Generally, differences between bedding systems with respect to cow welfare, comfort, hygiene, milk production, and mastitis favored use of sand-bedding materials; however, responses for all variables were within often-recommended thresholds for good management, regardless of bedding system. The use organic solids resulted in greater numbers of mammary infections than observed for sand-bedding systems. Further evaluation of preparatory, handling, and usage procedures for organic solids may offer some opportunity to minimize health risks associated with organic solids.

Technical Abstract: Our objective was to compare the composition of bedding materials and manure, cow welfare and hygiene assessments, measures of milk production and quality, and incidence of mastitis during a 3-yr trial with lactating Holstein cows housed in freestall barn containing 4 identical pens with 32 freestalls/pen. Bedding systems evaluated included deep-bedded organic manure solids (DBOS), shallow-bedded manure solids spread over mattresses (MAT), deep-bedded recycled sand (RS), and deep-bedded new sand (NS). The experiment was designed as a 4 × 4 Latin Square with 4 bedding systems and 4 experimental periods, but was terminated after 3 yr following discussions with the consulting statistician; therefore, data were analyzed as an incomplete Latin Square. A total of n = 734 mostly primiparous cows (n = 725 primiparous, n = 9 multiparous; 224 to 267 cows/yr) were enrolled in the trial. Before placement in freestalls, organic solids (OS) exhibited lower concentrations of DM (36.5 vs. 94.3%), and greater concentrations of volatile solids, C, N, NH4-N, P, water-extractable P, K, and S compared to RS or NS. Cow Comfort Index was greater for sand-bedded systems compared to those using OS (88.4 vs. 82.8%). Cows bedded in systems using OS (DBOS and MAT) exhibited greater mean hock scores (1 = no swelling, no hair loss; 2 = no swelling, bald area on hock) than those bedded in sand (1.25 vs. 1.04), but this effect was entirely associated with use of mattresses (MAT), which differed sharply from DBOS (1.42 vs. 1.07). Generally, hygiene scores for legs, flanks, and udders were numerically similar for DBOS, NS, and RS bedding systems, and differences between bedding systems were associated entirely with MAT, yielding detectable contrasts between MAT and DBOS for legs (2.94 vs. 2.20), flanks (2.34 vs. 1.68), and udders (1.83 vs. 1.38). No significant contrast comparing bedding systems was detected for measures of milk production or quality. Documented cases of clinical mastitis requiring treatment ranged from a low rate of 7.4 cases/yr for RS to a high of 23.1 cases/yr for DBOS, based on a mean enrollment of 60.7 to 63.0 cows/treatment/yr. Cows bedded with OS exhibited a greater incidence of mastitis than those bedded with sand (19.0 vs. 8.4 cases/yr), but there were no differences observed for comparisons within individual bedding-material types. Collectively, these results generally favored use of sand-bedding materials over systems using OS.