Is this a dairy cow or a beef cow? Cows dont need a certain amount of feed. Instead we like to balance rations based on pounds of protein, fiber carbohydrates and non-fiber carbohydrates then add in appropriate levels of vitamins and minerals. Grass hay provides a small amount of protein (10-14%) and legume hay (alfalfa) provides larger amounts of protein (20-24%). Both types of hay have fiber carbohydrates and this is balanced in a ration as NDF (neutral detergent fiber).
Dairy cows need protein for milk production and fetal growth. Beef cows need it primarily for fetal growth and smaller amounts of milk production. The fiber carbohydrates provide the rumen microbes with fuel to manufacture amino acids for growth and milk production.
As a general rule, cows can eat about 1.5 to 2% of their body weight in NDF and that is the way we balance the ration with a computer.
Dairy cows usually eat about 100 lbs of feed a day, beef cows about 30-50% of this amount depending on the type of feed. Dairy cows eat dry hay and haylage (fermented hay) and this account for about 30 lbs of their intake if quality is good. Beef cows would eat more hay and less starch so they could eat 15-20 lbs.
The main factor with hay is the quality. Good quality alfalfa hay is 20% protein, 30% ADF and 40% NDF when you test it at a lab (always recommended).
As a general rule they need to eat within these guidelines but it depends on the levels of the other things in their diet. I dont balance any of our cattle rations for sweet feed. The other components would be grain for energy and corn silage for energy and fiber. Hope that helps
They are definetly not getting enough feed. My answer was a bit complex above so my apologies for that! My rough calculations would be that they are getting about 13-15 lbs of feed per day total. This is probably about half of what they should get. Furthermore, if the body condition is poor then that is a sure sign they are lacking nutrients. This can be further compounded if the forage quality is poor because poor quality hay as a significant part that is not digestible.
My suggestion would be to try to obtain some good quality hay, feed about 20-30 lbs per cow per day (feed until 5-10% of feed per day is not consumed) and then supplement with a concentrate mix from a feed mill that contains corn and possibly a protein source such as distillers grains or soybean meal. This is expensive but is the only way to get weight back on the cows. You can often find a nutritionist to help you at a feed mill in your community. Also your local veterinary extension may assist you with exact ration guidelines. BotXXXXX XXXXXne is that these cattle are probably losing weight due to not enough feed.
Hope that helps