An Exploration of Relationships Between Dairy Cow Bunching Behavior and Environmental Factors
Applied Research
Jenifer Cruickshank
Extension Dairy Management faculty
Oregon State University Extension Service
Salem
Abstract
Bunching of cattle in barns is a common, seasonal problem on dairy farms. This behavior can lead to lower feed intake and increased risk of injury, particularly to teats. We wanted to know if environmental variables such as temperature humidity index (THI), wind, month, and time of day influence this detrimental behavior. An open-sided free-stall barn with two 110-cow pens oriented north to south, where bunching is regularly observed in the summer at the north end, served as the study site. Temperature and humidity were recorded in each quarter of each pen (east and west) from June 2017–November 2018. Over that same period, mounted cameras viewing each quadrant of the barn took still photos every 10 minutes. Photos from seven timepoints (6:30, 9:00, 11:00, 12:00, 17:00, 18:00, and 19:00) were scored for cow distribution in each pen. The scoring system ranged from -5 to +5 with zero indicating uniform distribution. A score of +3 would indicate that ~60% “extra” cows were in that quadrant of the barn, while a -4 would indicate that ~80% of cows were “missing” from that quadrant. Bunching was quantified by subtracting the south from the north end scores for each pen. Episodic measurements of ammonia and CO2 levels were also taken at the north and south ends of the barn. From mid-August 2018–November 2018, additional weather measurements from ~100m north of the barn, including wind direction and speed, were collected. Several statistical models were run in R: 1) score difference with month, time of day; 2) score difference sum with month, mean barn THI, the difference between the north and south end THI values; 3) score difference with month, time of day, THI, wind speed, wind direction. Ammonia and CO2 levels were uniform between north and south ends. We found that THI has strong influence on bunching, with the model fitting to the cubic degree. However, wind did not seem to have influenced bunching.
Poster has NOT been presented at any previous NACAA AM/PIC
This poster is being submitted for judging. It will be displayed at the AM/PIC if not selected as a State winner. The abstract will be published in the proceedings.
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Authors: Jenifer Cruickshank, Molly Stern
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Cruickshank, J. Extension Dairy Management faculty, Oregon State University, Oregon, 97301
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Stern, M. recently graduated BS student, Oregon State University, Oregon, 97331