Performance of lactating dairy cattle housed in a four-row freestall barn equipped with three different cooling systems

Kansas Agricultural Experiment Station Research Reports, Dec 1999

Ninety-three multiparous Holstein cows averaging 130 days in milk (DIM) were utilized to evaluate three cooling treatments installed in separate pens of a four-row freestall barn in northeast Kansas during the summer of 1999. Treatments were: 1) a double row of 36-inch fans spaced at 24-ft intervals over the freestalls; 2) a single row of 36-inch fans spaced at 24-ft intervals over the freestalls and over the cow feed line; and 3) a double row of 36-inch fans spaced at 24-ft intervals over the freestalls and a single row over the feed line. Each pen was equipped with identical sprinkler systems over the cow feed line. The 85-day study evaluated milk production, body condition score, respiration rate, and feed intake of cows cooled with the systems. Cows cooled with fans over the freestalls and feed line produced more (P< .05) milk (98.8 vs 93.9 lb/cow/day) than those cooled with fans only over the freestalls. Milk production was similar for cows cooled with fans over the freestalls and feed line, and doubling the number of fans over the freestalls had no apparent advantage. Cows in all treatments consumed similar amounts of feed, and those cooled only by fans over the freestalls tended to gain more body condition than cows in the other two treatments. Estimated increase in net income realized from using these cooling systems ranged from $3,500-6,100/year/pen.; Dairy Day, 1999, Kansas State University, Manhattan, KS, 1999;

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Performance of lactating dairy cattle housed in a four-row freestall barn equipped with three different cooling systems

Performance of lactating dair y cattle housed in a four-row freestall barn equipped with three different cooling systems John F. Smith Joseph P. Harner B. J. Pulkrabek D. T. McCarty Follow this and additional works at: http://newprairiepress.org/kaesrr Part of the Dairy Science Commons Recommended Citation - Article 14 This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1999 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. Brand names appearing in this publication are for product identification purposes only. K-State Research and Extension is an equal opportunity provider and employer. Performance of lactating dairy cattle housed in a four-row freestall barn equipped with three different cooling systems Abstract Ninety-three multiparous Holstein cows averaging 130 days in milk (DIM) were utilized to evaluate three cooling treatments installed in separate pens of a four-row freestall barn in northeast Kansas during the summer of 1999. Treatments were: 1) a double row of 36-inch fans spaced at 24-ft intervals over the freestalls; 2) a single row of 36-inch fans spaced at 24-ft intervals over the freestalls and over the cow feed line; and 3) a double row of 36-inch fans spaced at 24-ft intervals over the freestalls and a single row over the feed line. Each pen was equipped with identical sprinkler systems over the cow feed line. The 85-day study evaluated milk production, body condition score, respiration rate, and feed intake of cows cooled with the systems. Cows cooled with fans over the freestalls and feed line produced more (P< .05) milk (98.8 vs 93.9 lb/cow/day) than those cooled with fans only over the freestalls. Milk production was similar for cows cooled with fans over the freestalls and feed line, and doubling the number of fans over the freestalls had no apparent advantage. Cows in all treatments consumed similar amounts of feed, and those cooled only by fans over the freestalls tended to gain more body condition than cows in the other two treatments. Estimated increase in net income realized from using these cooling systems ranged from $3,500-6,100/year/pen.; Dairy Day, 1999, Kansas State University, Manhattan, KS, 1999; Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 License. This Research Report article is available in Kansas Agricultural Experiment Station Research Reports: http://newprairiepress.org/ kaesrr/vol0/iss2/14 Dairy Day 1999 PERFORMANCE OF LACTATING DAIRY CATTLE HOUSED IN A FOUR-ROW FREESTALL BARN EQUIPPED WITH THREE DIFFERENT COOLING SYSTEMS Summary Ninety-three multiparous Holstein cows averaging 130 days in milk (DIM) were utilized to evaluate three cooling treatments installed in separate pens of a four-row freestall barn in northeast Kansas during the summer of 1999. Treatments were: 1) a double row of 36-inch fans spaced at 24-ft intervals over the freestalls; 2) a single row of 36-inch fans spaced at 24-ft intervals over the freestalls and over the cow feed line; and 3) a double row of 36-inch fans spaced at 24-ft intervals over the freestalls and a single row over the feed line. Each pen was equipped with identical sprinkler systems over the cow feed line. The 85-day study evaluated milk production, body condition score, respiration rate, and feed intake of cows cooled with the systems. Cows cooled with fans over the freestalls and feed line produced more (P< .05) milk (98.8 vs 93.9 lb/cow/day) than those cooled with fans only over the freestalls. Milk production was similar for cows cooled with fans over the freestalls and feed line, and doubling the number of fans over the freestalls had no apparent advantage. Cows in all treatments consumed similar amounts of feed, and those cooled only by fans over the freestalls tended to gain more body condition than cows in the other two treatments. Estimated increase in net income realized from using these cooling systems ranged from $3,500-6,100/year/pen. (Key Words: Environmental Stress, Heat Stress, Milk Production.) Introduction Many Kansas dairies have chosen fourrow freestall barns for cow housing. Freestall barns provide shade to protect dairy cattle from most of the sun’s rays. However, cattle still experience heat stress when the temperature-humidity index exceeds 72. Without additional cooling, cattle in four-row freestall barns will experience heat stress during the summer months in Kansas. Cows lose heat to the environment mostly by evaporation. Evaporation in the lungs helps cool the cow, and as respiration rate increases, greater evaporation occurs. However, the cow’s ability to control heat stress in this manner is limited, and other methods of cooling can reduce the negative effects of heat stress. The purpose of this study was to evaluate the effectiveness of three different cooling systems installed in a four-row freestall barn. Procedures Ninety-three multiparous Holstein cows averaging 130 days in milk (DIM) were assigned to one of three cooling treatments. Cows were blocked by lactation number, DIM, and production. Cows were housed in each of three identical 100-cow pens on a commercial dairy farm equipped with 84 freestalls per pen (Table 1). The barn was 100 ft in width and 420 ft in length. The sidewall height was 12 ft, and the roof had a 4/12 slope. Treatment one (2S) was located in the southeast quarter of the building and had a 1Department of Biological and Agricultural Engineering. double row of fans (14 36-inch-diameter circulation fans with 0.5 horsepower motors) mounted every 24 ft over the freestalls. Each fan had an air delivery rate of 10,000-11,500 cfm and was angled down at 30E. Treatment two (F+S) was located in the southwest quarter of the building and had a row of fans (seven 36-inch-diameter circulation fans with 0.5 horsepower motors) mounted over the freestalls and another row (seven 36-inch-diameter circulation fans with 0.5 horsepower motors) over the feed line. Both rows of fans were angled downward at 30E and had the same air delivery rate as those listed above. Treatment three (F+2S) was located in the northwest quarter of the building and had a double row of fans (14 36-inch-diameter circulation fans with 0.5 horsepower motors) mounted every 24 ft over the freestalls and a row of fans (seven 36-inch-diameter circulation fans with 0.5 horsepower motors) mounted over the feed line. The angle and air delivery rate were the same as described above. Each pen was equipped with similar sprinkler systems consisting of 2.5 gal/hr nozzles spaced every 78 inches on center at a height of 8 ft above the headlocks. Sprinklers were on a 15-minute cycle, with 3 minutes on and 12 minutes off. They were activated when the temperature was above 75EF. The designed application rate was .04 inches/sq ft of surface area, which consisted of 12 sq ft/headlock or 24-inch feeding space. Total application rate was 50 gal/ cycle. Fans of all treatments were activated when the temperature was above 70EF both day and night. Cows were fed the same total mixed ration three or four times daily for 105% of ad libitum intake. Amounts fed and refused were recorded daily. Intake data were collected on a pen basis and included 69 additional cows in each pen. Cows were milked 3× and had similar access to water. Animals eligible for rbST were injected at 14-day intervals throughout the trial. Daily milk production was measured for a 24-hour period every 2 weeks throughout the trial. Respiration rates were measured four times during periods of heat stress. Rates were taken in the morning and again in the afternoon on 50 cows/pen. Results and Discussion Initial treatment averages (Table 2) for DIM and milk production were not different. Cows cooled with the F+S system produced 4.5 lb more (P<.05) milk than those in the 2S system, and those under the F+2S system were intermediate. Dry matter intake was numerically similar for all treatments. All cows increased body condition during the trial. Cows under the 2S system tended to gain more condition than the F+S cows. This likely was due to similar intakes, but lower production in the 2S treatment. Respiration rates both morning and afternoon (Figure 1) were greatest for cows in the 2S treatment but followed similar trends for cows in the other treatments. Respiration rates increased 10 to 14% during the afternoon. Cows housed in the F+S system had the lowest percentage increase. The smaller percentage increase in respiration rate and increased milk production resulting from the F+S system indicate that it was the most effective system in reducing heat stress of dairy cattle. An economic analysis of the three systems is shown in Table 3. Based on the assumption that post-peak milk production normally declines 5% each month and that without any heat stress control measures other than shade, milk production would decline an additional 20% during the summer months, these methods of heat abatement will increase gross farm income $8,157 to $11,647/pen/yr or $81.57 to $116.47/cow/yr. Net income, after all capital investment, operational, and increased feed costs have been removed, would increase from $35.82 to $64.04/cow/yr. The average Kansas dairy farm could increase annual net farm income by $3,582 to $6,404 by utilizing one of these systems. This profit would pay for the entire investment in less than 2 years. Conclusions The results of this study clearly show that cooling cows can pay big dividends. The systems implemented in this study are cost effective and available to any Kansas dairy producer. Based on the results presented, four-row freestall barns are cooled most effectively when sprinklers are used on the feed line and rows of fans are placed on both the feed line and over the freestalls. Design criteria presented here have been effective in reducing the effects of heat stress in four-row freestall barns. Recommendations on deviations from these design criteria require additional study. 1Building description: building type, 4 row; orientation, east-west (2% slope to west); dimensions, width (100 ft), length (420 ft), sidewall height (12 ft), roof slope (4/12); and configuration, 4 pens with 84 stalls per pen and 100 headlocks per pen. 22F = two rows of fans over freestalls, F+S = one row of fans over the feed line and one row of fans over the freestalls, and F+2S=one row of fans over the feed line and two rows of fans over the freestalls. feed line 25 180E on - 3 min off - 12 min 36 (½ hp) 1,900 0 Cooling System2 F+S feed line 25 180E on - 3 min off - 12 min 8 1 1 8 16 24 950 800 36 (½ hp) F+2S feed line 25 180E on - 3 min off - 12 min 8 2 1 8 24 24 36 (½ hp) 1,900 800 Milk Yield, Body Condition, and Feed Intake of Dairy Cows Housed in a Four-Row Freestall Barn with Three Different Cooling Systems Change in body condition +.52 +.39 +.21 .14 x,yMeans with uncommon superscripts differ (P<0.05). 12S = two rows of fans over freestalls, F+S = one row of fans over the feed line and one row of fans over the freestalls, F+2S = one row of fans over the feed line and two rows of fans over the freestalls, and SEM = standard error of mean. 2S = two rows of fans over freestalls, F&S = one row of fans over the feedline and one row of fans over the freestalls and F&2S = one row of fans over the feedline and two rows of fans over the freestalls. Average Respiration Rates of Cows Cooled with Three Different Spray and Fan Systems in a Four-Row Freestall Barn. Beginning (6/12/99) milk production (lb/cow/day) Estimated milk production w/o cooling (lb/cow/day) Average milk production w/ cooling (lb/cow/day) Cooling response (lb/cow/day) Total extra income due to cooling ($/pen) Fixed and installation cost of fans ($/pen) Fixed and installation cost of sprinkler ($/pen) Total fixed cost of cooling systems ($/pen) Annual fixed fan cost ($/pen/yr) Annual fixed sprinkler cost ($/pen/yr) Total cost of electricity for fans ($/pen/yr) Total electricity cost per stall ($/stall/yr) Total sprinkler water usage (gal/pen/yr) Cost of water for sprinklers ($/pen/yr) Water cost per stall ($/stall/yr) Variable cooling cost for water and electricity ($/pen/yr) Additional feed cost per cow ($/cow/day) Additional feed cost per pen ($/pen/year) Interest rate if money was invested (%) Return on money if invested ($/yr) Gross income due to cooling system ($/pen/yr) Total operating and feed cost ($/pen/yr) 84 cows or stalls per pen Calculations over a 85 days of heat stress Milk price = $13/cwt Rural water cost = $1.60/1000 gal 20% reduction in milk production with no cooling


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John F. Smith, Joseph P. Harner, B. J. Pulkrabek, D. T. McCarty. Performance of lactating dairy cattle housed in a four-row freestall barn equipped with three different cooling systems, Kansas Agricultural Experiment Station Research Reports, 1999,