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  • Jason Duggin University of Georgia

Angus Advisor: Southern Region

If there was a lesson to avoid learning the hard way, it would be a breeding season with poor, untested hay. If you haven’t tested your hay, that approximate $30 dollars for each lot of hay could be the most important investment of the year. The importance of a forage analysis cannot be overstated. A producer may feel confident their hay is “high” quality, but there is only one way to be sure the herd is getting sufficient fuel — test it.  

If hay is the main forage during breeding season and either protein or energy are not meeting the recommended requirements below, we can plan on cows calving at least three weeks later the following year. The result could be 50 lb.-lighter calves at weaning time. We may also have 2- and 3-year-old females that don’t breed back at all in a defined calving season.  

However, with a forage analysis in hand, producers can know how much of a gap might exist and plan accordingly. The “UGA Basic Balancer” can be found online at under the tools section to help assist in ration planning along with your Extension agent or nutritionist. 

After calving, a cow’s nutritional requirements will increase. Assuming a body condition score (BCS) of 5 for cows and 6 for heifers, visualize they will lose roughly one BCS, approximately 80 lb. of energy reserves. During the 50 days from calving to peak lactation, nutritional requirements will increase quickly. 

Peak lactation requirements are 12% crude protein (CP) and 60% TDN (total digestible nutrients; energy). Cows in late lactation should be bred, but they still require 9-10% CP and 55% TDN. Dry cows’ BCS should be monitored, particularly during the cold snaps to come. She is still pregnant and needs to provide essential nutrients to the calf in utero. Dry cows still need at least 7% crude protein and 50% TDN on a dry-matter basis. Please note the nutritional requirements will gradually increase until calving.    

If we test a cutting of hay and the results are 8% CP and 53% TDN, we now know that this hay is not sufficient through a breeding season. Look for additional sources of protein and energy to fill those gaps. Producers who look to fill these gaps should have improved conception rates, earlier calving dates and heavier weaning weights. The alternative can be harsh. 

Remember protein supplementation alone will not overcome an TDN deficit. One option may be commodity byproducts or blends. Corn gluten and soybean hulls are a go-to in some areas of the Southeast. Study the do’s and don’ts of any byproducts used. Corn gluten exceeding recommended levels can be lethal. 

In summary, a forage analysis may save your cows, your calf crops and the bottom line.

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