Post by aww12 on Jun 9, 2016 9:58:03 GMT -5
The 1:3 rule of thumb:
Doesn't take into consideration the quality and quantity of the forage. The quality of the forage is an important key in balancing a ration. As the quality of forage decreases, so does the amount the cow can eat of it.
Doesn't take into consideration the component level of the milk. Milk that is 6% butterfat takes more energy to produce than does milk that is 3%.
Doesn't take into consideration the cow- how much does she weigh, is she young and still growing?
Doesn't take into consideration the grain. "A rose is a rose is a rose" wouldn't be accepted by a horticulturalist. "A pound of grain is a pound of grain is a pound of grain" wouldn't be accepted by a nutritionist. Ground ear corn has a different energy level than steam flaked corn.
Doesn't take into consideration the stage of lactation and the lactation curve, also known as lead feeding.
Doesn't take into consideration economic questions- what is an additional pound of milk worth, what is the cost of grain and forage?
Offers simplicity at the cost of understanding the math and science.
digitalcommons.unl.edu/cgi/viewcontent.cgi?article=4817&context=extensionhist This publication is 50 years old and is showing its age, but is worth studying. For instance, you can compare the grain recommendation for a cow producing 30 pounds of 3.5% milk on excellent forage with a cow producing 30 pounds of 6% milk on average forage. Another idea would be to pick a spot in the chart that is in the general range of your situation - say your forages are average, butterfat is usually about 4.5%, and production runs between 30 and 40 pounds- and see or have someone at the feed mill see how close the chart may be for your situation. You can then make a similar chart that is closer to your situation, maybe one for summer and pasture and one for winter hay feeding.