The Milk Producer - February 2011 - (Page 34)

APPLIEDSCIENCE By Marina von Keyserlingk and Dan Weary A practical option While dairy cows enjoy all the comforts modern freestall barns offer, letting them get outside regularly can enhance their health G iven our climate, providing your cows with continuous pasture access is not an option for many Canadian dairy producers. Giving your herd even temporary access to grass, however, can promote their health and welfare without sacrificing milk production. Lack of pasture access has been linked with higher lameness rates. Pasture is also perceived as providing a more natural environment for cows. Lack of access is often viewed as a welfare concern, and organic standards typically require some pasturing. Yet many producers prefer housing systems based on zero pasture access. A modern freestall barn is designed to provide a high degree of cow comfort. One of these well-designed structures provides cows with a comfortable place to lie down, protection from the elements and free access to a well-balanced diet that helps maintain high milk production levels. If cows can use a well-designed freestall barn, do they really prefer or need pasture access? What are the advantages and disadvantages? In one study, University of British Columbia researchers compared lameness in cows restricted to a freestall barn with cows restricted to pasture for five weeks. They used gait-scoring to assess lameness: cows with a gait-score of one were considered healthy and cows scored five were considered severely lame. Researchers gait-scored 72 dairy cows and divided them into 18 groups of four animals. They all had calved two or more times and were in mid to late lactation. Nine groups were restricted to each treatment for five continuous weeks sometime during July through October. Average gait scores for the pasture and freestall treatments were both three when the trial began. Cows on pasture grazed and were fed concentrate after each milking before returning to pasture. Cows kept in the barn were fed a total mixed ration (TMR). All cows were gait-scored weekly, and lying time was measured using a data logger attached to each animal’s hind leg. Depending on the weather, cows will choose pasture or staying in the barn. Average gait score improved for pastured cows, despite reduced lying time. Scores for freestall cows remained stable or worsened. Gait improvement was most apparent for cows with the highest initial scores, suggesting pasture access particularly benefits more severely lame animals. This study indicates you can improve cow lameness by providing even temporary pasture access, but this might not be true for other aspects of cow welfare. Although keeping cows outside on grass is perceived as more natural than keeping them inside, most pasture provides little or no shade. This potentially increases 34 | February 2011 | MilkPRODUCER

Table of Contents for the Digital Edition of The Milk Producer - February 2011

The Milk Producer - February 2011
Contents
Editor's Notes
DFO Chair's Message
Dairy Update
Industry Roundup
DFC Promotion
Issues Update
Research
Applied Science
Ruminations
Rearing Replacements
Calf Health
Markets
Markets
New 'N' Noted
Back Forty

The Milk Producer - February 2011