Why the Packer Loves Cowmen: Part I, The Reproductive Index

Santa Gertrudis cows and calves, The calf has and Electronic Ear Tag and herd management tag (yellow).

by Dr. Jimmy T (Gunny) LaBaume

Here is something that is sure to surprise you.

Let’s calculate the number of calves weaned per breeding animal, including bulls, replacement heifers and cows using ”typical” assumptions: 1) A less than 80% conception rate; 2) Of the cows pregnant, 90% will wean a calf e.g. between 70 and 75 calves per 100 cows exposed to the bull; 3) Replacement heifers are bred to calve at two years of age and 70% of these conceive and; 4) One bull for 25 cows.

So, out of 100 cows, herd composition at weaning and pregnancy testing would be:

Pregnant cows 80

Open cows 20

Pregnant replacements 20

Open replacements 9

Yearling heifers 29

Bulls 5

Total Herd 163

In sum, the 100 pregnant cows and heifers would wean 90 calves but, to do this, it takes 163 breeding animals. This is what Parsons calls, the “reproductive index” = 90/163 = .55 calves per breeding animal. So, if the calf weighs 500 lbs and is worth $750, the income per breeding animal is only $412.50 ($750 X .55).

Then, to arrive at gross margin we have to deduct death losses, depreciation, vet medicine, supplements, marketing expenses and interest on capital.

And then the result has to cover the overheads—land rent, salaries, etc.

There are two ways improve the reproductive index; 1) increase the calf crop and/or 2) reduce the number of breeding animals.

The only way to reduce the number of breeding animals is to reduce the number of bulls and replacement heifers. And in turn, to reduce replacement heifers, conception rates must be improved.

There are three ways to cut back on breeding animals without reducing the calf crop: 1) improve herd fertility so that fewer replacement heifers are needed; 2) increase the useful life of your mamma cows and 3) find ways to cut back on the number of bulls.

We will deal with these in subsequent parts.

After: Parsons, Stanly D. Putting Profit into Ranching

Dr. Jimmy T (Gunny) LaBaume (send him mail) is President & CEO, Land & Livestock International, Inc. providing a complete line of management & consulting services to the range livestock industry.

Related articles

• Bull buying made simple (blackinkwithcab.com)
• Making Steak… (ladyofag.wordpress.com)
• It’s a Heifer! And a Bull? (heimdairy.wordpress.com)
• Prepping for no rain (blackinkwithcab.com)
• Cattle Profits: a breakdown (heritagebreedsfarm.com)
• A Calf Is Born (heimdairy.wordpress.com)
• Numbers, – what do they all mean? (hazelbluffangus.wordpress.com)