HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Clark, A. K. Articles by Rakes, A. H. Search for Related Content PubMed PubMed Citation Articles by Clark, A. K. Articles by Rakes, A. H.

Effect of Methionine Hydroxy Analog Supplementation on Dairy Cattle Hoof Growth and Composition^1,2,

Department of Animal Science, North Carolina State University, Raleigh 27650

ABSTRACT

Fifty lactating Holstein cows were assigned randomly to one of two treatments, control and control plus approximately 30 g methionine hydroxy analog, and confined on concrete for 11 mo. The control diet consisted of sorghum silage and concentrate fed as a blended ration. Sulfur contents of dry matter were .12% and .16% for control and methionine hydroxy analog rations. Hoof growth and hardness were measured on front and rear right abaxial claws in the dorsal and lateral regions. Hoof growth rates were measured for four periods; summer-fall, fall-winter, winter-spring, and spring-summer, each 70 to 90 days. Hooves of cows fed methionine hydroxy analog grew faster than those of control cows during spring-summer in all regions. Variations of growth rates of hooves were seasonal and tended to follow variations in daily photoperiod. Wear rates were not affected significantly by treatment. Hooves of cows fed methionine hydroxy analog were softer in the top dorsal region at the end of winter-spring and in the dorsal toe region at the end of spring-summer. All other locations were not affected significantly by treatment. The toe region was harder than the top of the hoof. Cows fed methionine hydroxy analog had less cysteine and proline in hoof than control cows and greater percentages of methionine lysine, tyrosine, and glutamic acid. These results suggest that a decrease of disulfide bonding occurred in the hoof tissue of cows fed methionine hydroxy analog. Cows fed methionine hydroxy analog produced more actual milk, milk fat, and 4% fat-corrected milk during 180 days than did control cows.

¹ Paper No. 6847 of the Journal Series of North Carolina Agricultural Research Service, Raleigh, NC.

² Mention of a proprietary product does not constitute a guarantee or warranty of the product by the North Carolina Agricultural Research Service and does not imply its approval to the exclusion of other products that may also be suitable.

³ Department of Dairy Science, South Dakota State University, Brookings, SD 57007.