Estimating Hay Needs
The following article was written by Mark Z. Johnson, Oklahoma State University Extension Beef Cattle Breeding Specialist. The article addresses some basic rules of thumb to follow when determining the hay supplies ranchers will need to sustain the cow herd over the next few months.
1. Determine your average mature cow size. This can be done by weighing your 4 – 7 year old cows and calculating the average weight. From mature cow size, approximate the amount of forage dry matter cows needed to consume per year or per day. For example: a 1,000 pound cow will consume about 26 pounds of forage dry matter per day. A 1,400 pound cow will consume about 36.4 pounds of forage dry matter per day.
2. Determine your cow inventory
3. Estimate the amount of time you expect to be feeding cows.
From this information you can calculate the total amount of hay needed. For example: 100 cows weighing 1,400 pounds will consume about 3640 pounds of hay per day. Take into account that a certain amount of the hay fed will be wasted and there will be a certain amount of spoilage of each bale fed that won’t be consumed. With this in mind, add another 10% to the daily total to bump it up to about 4000 pounds (2 tons) per day.
Remember the amount of hay wasted or spoiled could be higher. If we are feeding hay from last year expect a higher percentage spoiled in each bale.
If expecting to feed hay from mid-October to mid-May, that is approximately 200 days of hay feeding. 4000 pounds of hay needed per day x 200 days equals a total of 800,000 pounds (400 ton) of forage dry matter that cows will consume over this time. If we feeding or buying large rounds with an average weight of 1,250 pounds that equates to 640 (800,000 divided by 1,250) big bales needed to sustain 100 cows.
If possible, purchase hay by the ton. It leads to less error in securing the amount of hay needed to purchase or have on inventory. If buying hay by the bale is your only option, make sure to weigh enough of the bales to have an accurate representation of bale weight. Also, take into account the amount of spoilage of each bale. Other factors such as weather, stage of gestation or lactating versus dry cows will obviously impact nutritional requirements of cows from day to day. Provide hay and other nutritional supplementation accordingly.
Montana State University, U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach.
