The Milk Producer - April 2011 - (Page 36)

RUMINATIONS By Barry Potter Pasture pointers When you put your dairy herd out on grass, you have to change your management to maintain production levels A s they enjoy a cold glass of milk, many consumers likely .contemplate the image of cows grazing lush green pastures while the sun sets on another summer day. Turning cows out on grass can also mean cheaper feed costs for you and a way to provide exercise for your cows. However, managing lactating cows on pasture presents its own set of challenges, particularly maintaining production and feed intake. Cows may struggle to eat enough to meet their dietary requirements. Milk production tends to drop when cows graze, often with fat and protein percentages. A recent Penn State University study looking at how pasture management affects dry matter intake suggests ways of meeting these challenges. Research on grazing shows Holstein cows eat the equivalent of about three per cent of their body weight per day on pasture. How effectively a cow harvests grass determines intake. Penn State researchers actually de- The biggest factor influencing feed intake from pasture is bite size, or how much forage a cow harvests with every bite. veloped an equation to calculate how much a cow consumes on pasture. Intake equals grazing time, multiplied by biting rate, multiplied by bite size. You can influence grazing time by regularly providing your cows with fresh pasture, the equivalent of pushing up feed to the bunk in confinement operations. You have no control over biting rate—the number of times per minute cows decide to clip the grass with their teeth. Grass height and density establish how much forage is available to cows each time they bite, determining bite size. Ideal grass height is eight to 12 inches (20 to 30 centimetres). This is critical to maximize bite size. Higher yielding cows eat more than lower yielding cows. They graze more and have more bites per minute. The biggest factor influencing pasture intake is bite size, the amount of forage intake per bite. The Penn State study grazed two groups of high-producing Holstein cows on different pasture amounts. One group was offered the forage equivalent of 55 pounds of dry matter (DM) per day, the other 90 Ruminations is prepared by Ontario Ministry of Agriculture, Food and Rural Affairs livestock technology specialists to provide information you can use on your farm. 36 | April 2011 | MilkPRODUCER

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

The Milk Producer - April 2011
Contents
Editor's Notes
DFO Chair's Message
Dairy Update
Industry Roundup
DFC Promotion
Cover Story
Producer Profile
Research
Applied Science
Ruminations
Calf Rearing
Markets
New 'N' Noted
Back Forty

The Milk Producer - April 2011