AS-396 • 1977
animal sciences  beef
Selection. Management and nutrition  of the cow  Herd
L. A. Nelson, W. L. Singleton and K. S. Hendrix, Animal Sciences Department, Purdue University
The most important factor affecting profit in a cow-calf enterprise is pounds of calf weaned per cow exposed during the previous breeding season. This pounds-of-calf-weaned factor is influenced by breeding stock selection, herd management and nutrition.
The purpose of this publication is to present facts and make recommendations that will help the cow-calf producer: (1) decide on the type of female breeding herd best suited to his situation, (2) develop a selection program for quality herd replacements, and (3) apply those feeding and management practices that insure top animal performance while minimizing calf loss. A list of related Purdue Extension publications is presented on page 6.
SELECTION CONSIDERATIONS
The first step toward a successful and profitable cow-calf enterprise is selection of heifers or cows that will settle early in the breeding season and wean heavy, high quality calves every 12 months.
Start with Heifers or Cows?
For an established producer, the best source of heifers is usually his own herd. However, one getting started in the cow-calf business must initially purchase his breeding stock. Here are four ways to start the cow herd. The advantages and disadvantages of each are summarized in Table 1.
7. Heifer Calves without Performance Records. Large groups of good heifer calves are most numerous in the fall. Those selected should be individually weighed and identified at time of purchase, then developed on a high-roughage
growing ration. Before the breeding season, weigh the heifers again, and select for breeding the larger ones that have gained well, but are not overfat.
2.	Open Heifers with Performance Records. Select such heifers on the basis of their 205-day and 365-day weights and weight ratios. Consider only those that have performed in the top three-fourths of the herd—that is, with weight ratios above 90. Purchase them at 12-13 months of age so they can be isolated 30 to 60 days before the breeding season begins (when they average 15 months of age).
3.	Bred Yearling Heifers. Purchase about 25 percent more heifers than you need in the herd. It’s advisable either to have them pregnancy-tested before paying for them, or to buy them subject to being guaranteed pregnant. Also consider the potential for calving problems resulting from the sire to which they are mated. Cull the least desirable heifers prior to calving; or better yet, wait until they calve, and sell those that lose their calves at or soon after parturition because of calving difficulty, failure to claim their calf, etc.
4.	Mature Cows. Generally, it’s not advisable to buy mature cows. Chances are they are being culled from someone's herd because of poor reproductive performance, light calves, old age, mastitis or other health problems. However, if cows are nursing calves, the probability of infertility is less, and you can sometimes get a good three-in-one package if the cows are rebred.
Before buying breeding stock, observe them closely for potential health problems, such as internal and external parasites, and have them tested by a veterinarian for tuberculosis, brucellosis and leptospirosis. Also, isolate for 30 to 60 days after they arrive on your farm.