Effects of winter housing systems on production, economics, body weight, body condition score, and bedding cultures for organic dairy cows

摘要

Certified-organic dairy cows (n = 268) were usedto evaluate the effect of 2 winter (December to April)housing systems on milk production, somatic cell score(SCS), body weight, body condition score (BCS), andeconomics across 3 winter seasons (2013, 2014, and2015). Bedding cultures from the housing systems werealso evaluated. Cows were randomly assigned to 2treatments (2 replicates per group): (1) outdoor (strawpack, n = 140) or (2) indoor (3-sided compost beddedpack barn, n = 128). Cows calved during 2 seasons(spring or fall) at the University of Minnesota WestCentral Research and Outreach Center, Morris, Minnesota,organic dairy. Milk, fat, and protein productionand SCS were recorded from monthly milk recording.Body weight and BCS were recorded biweekly as cowsexited the milking parlor. Bedding cultures from thehousing systems were collected biweekly. Costs forkey inputs and the price received for milk productionwere recorded for the study period and averaged foruse in the profitability analysis. Energy-corrected milkand SCS were not different for the outdoor (15.1 kg/d,2.64) and indoor (15.7 kg/d, 2.57) housing systems, respectively.In addition, cows in the outdoor and indoorhousing systems were not different for body weight(528 vs. 534 kg) and BCS (3.22 vs. 3.23), respectively.Daily dry matter intake was 19.1 kg/d for the outdoorcows and 19.6 kg/d for indoor cows. The total bacteriacount from bedding samples tended to be lower in theoutdoor (13.0 log_(10) cfu/mL) compared with the indoor(14.9 log_(10) cfu/mL) system. Milk revenue and feed costwere not different for the 2 housing systems. Labor andbedding costs were lower and net return was higher forthe outdoor housing system. The outdoor straw packsystem had a $1.42/cow per day net return advantageover the indoor compost bedded pack barn. In summary,lactating cows housed outdoors on straw-beddedpacks did not differ for production or SCS, or for bodyweight, BCS, or dry matter intake, but had greaterprofitability than cows housed in an indoor compostbedded pack barn.