Analysis of Particle Size and Organic Matter in Recycled Sand Bedding

Recycled sand bedding is widely used and can support both dairy cow health and comfort if appropriately managed. Recycled sand, if free of organic matter, is an inhospitable environment for pathogen growth. Sand particle size influences hoof health and lameness, and is another factor to evaluate in recycled sand. Particle size and organic matter content of recycled sand were analyzed at Lake Breeze Dairy, LLC in Malone, WI. During the month of July 2016, samples of recycled sand bedding were taken two times a week from the sand lane (86.9 m long) at 21.3, 42.7, 64.0, and 85.3 m from the wash out point. Particle size was analyzed using sieves with 4750, 2000, 600, and 300 μm openings. For each location, a 250 g sample was dried in a microwave oven until reaching stable mass. The dry samples were sieved and percent composition was calculated for three groupings of particle size: <600 μm (small), 600-2,000 μm (medium), and >2000 μm (large). Approximately 600 g of the unsieved sand was taken from each sampling location for analysis of organic matter content determined by ashing (Dairyland Laboratories, Arcadia, WI). The results are summarized in table 1. Sampling location within sand lane affected particle size with the 21.3 m location being significantly different than the other three locations (P < 0.01). Organic matter and sand volume decreased as distance within sand lane increased (P = 0.01). The highest concentration of quality sand was located at 21.3 m with significant declines in sand particle size, cleanliness, and volume at greater distances.

Table 1. Characteristics of recycled sand bedding at different locations in sand lane
	Sample location1, m					P-value
	21.3	42.7	64.0	85.3	SEM	Location	Day
Small, %	48.54a	83.55b	79.35b	77.03b	3.36	< 0.01	0.05
Medium %	44.48a	14.27b	18.14b	19.52b	3.13	< 0.01	0.06
Large %	7.09a	2.33b	2.21b	2.78b	0.60	< 0.01	0.02
Organic Matter %	3.86a	8.01ab	8.77b	9.50b	1.17	0.01	0.96
Sand Volume %	64.00a	27.00b	7.00c	2.50c	1.65	< 0.01	0.89
1Distance from washout point, m. a,b,c Superscripts reflect location differences (P ≤ 0.05)