Table 27.1 summarizes the cost structure of producing a heifer that will join the mature cow herd when she is confirmed pregnant.² This budget assumes that the heifer is born in the spring and weaned the following November. She will be bred the following summer and then subsequently calve as a 2 year old. The single biggest expense associated with the heifer development program is the opportunity cost of the market value of the heifer at weaning. This $825.46 cost (Period 1: conception to weaning) is incurred when the producer decides to keep her in the replacement pool as opposed to selling her at market value.

Costs associated from heifer weaning until the start of the breeding season are primarily associated with the winter feeding program and summer grazing (Table 27.1). Over 85% of this $321 cost is accounted for by feed, labor, yardage, and interest. Drylot rations or supplementation programs for heifers on grass need to balance feed costs with adequate growth performance. This emphasizes the need for sound nutritional consultation during this time, especially when feed ingredient prices are high. The animal health program (including death loss) and grazing costs (pasture rent equivalent) make up the remainder of the inputs during this time frame.

The costs associated with developing replacements through the end of the breeding season are also illustrated in Table 27.1. This $129 estimated cost is primarily associated with grazing and breeding costs. The grazing season is estimated to last 4 months at $13.60 per month. This budget assumes the purchase of a $4000 bull that will breed 20 heifers per year for a total of four breeding seasons. This breeding cost also considers the annual cost of feeding the bull, interest on the initial investment, and the bull’s salvage value when culled. This gives a total investment of $1275 to carry a replacement heifer to approximately 18–20 months of age (pregnancy examination).

Finally, the cost of heifer development must take into account the level of reproductive performance (percent pregnant) and cash value of the open heifer. In this example an 85% pregnancy rate increases the cost of production to $1500 for each pregnant heifer. The income from the sale of open heifers is then credited to the heifer enterprise, bringing the final cost to $1354 per pregnant heifer. This total represents a $529 developmental cash cost being added to the $825.46 opportunity cost incurred at the time of initial selection. With this magnitude of capital outlay, it is critical that these heifers be adequately developed to ensure optimum reproductive performance and longevity.

Selection at weaning

Recent surveys indicate that approximately 85% of beef replacement heifers were raised on the operation where they calved.³ Although the majority of herds in the United States utilize some form of individual cow and calf identification, this information is underutilized when it comes to making management decisions. Therefore it is critical that the practitioner help the client understand the importance of accurate data collection as it relates to the heifer development enterprise. Calf birth date, dystocia score or birthweight, female temperament, and calf weaning weight can all be used to make inferences about individual cow productivity over time. This information can then be used to make post-weaning selection decisions easier.

The process of heifer development normally begins at the time of weaning with the initial selection of potential replacements. Females should be selected based on age, weight, temperament, and the productivity of their dam. Musculoskeletal soundness must also be evaluated as poor feet and leg structure can have a negative impact on productive longevity.⁴ Selecting replacements from calves born in the first half of the calving season will increase the chance of the female reaching puberty by the time the breeding season starts.^5,6 Since the age and breed of the potential replacement is already established by the producer, weaning weight becomes the primary selection parameter and the basis for the developmental program.

Regardless of their birth date, the entire calf crop is typically weaned on the same day, so uniformity of the group of replacements may be an issue. Sorting heifers by weight and frame score is normally the first step in narrowing the pool of replacements at weaning.⁵ Economic considerations should be evaluated when there is a wide disparity in heifer weights. Heifers which are too large (frame score) or too light (weight) may be targeted for culling in order to improve the economic efficiency of the replacement program. Beef operations that have a sound replacement development program should only need to retain an additional 10–20% more weaned heifers than they need to become pregnant. This will enable them to maintain current herd size and avoid the opportunity cost of retaining more heifers than needed.

Pre-breeding nutritional management

Based on a heifer’s genetics and expected mature size, a target weight can be selected and the feeding program tailored to meet the needed average daily gain.^5–7 Target weight is simply an estimation of the weight at which individual heifers will reach puberty. Provided we know the weaning weight, target weight, and number of calendar days before the start of the breeding season, rations can be constructed to ensure that heifers reach puberty in a timely fashion. Typically, the rate of gain needed will fall into the range 0.5–0.8 kg/day and represent a total gain of approximately 91 kg for heifers of British breeding.

Traditional intensive developmental programs have emphasized the need for heifers to reach approximately 60–65% of their expected mature weight prior to breeding.^5–7 This practice is utilized to ensure that heifers reach puberty prior to the start of the breeding season. This ensures that heifers are cycling at the beginning of the breeding season and increases the chance of early pregnancies. Recent Nebraska research has looked at the reproductive performance of heifers that were targeted to reach only 50–55% of their expected mature weight.^8–10 These heifers are overwintered on relatively poor forage (winter range or corn stalks) with supplemental feed. In these studies, reproductive performance was not different between heifers developed to reach 55% versus 60% of their expected mature weight (Table 27.2). However, heifers developed to only 50% of their expected mature weight run the risk of conceiving later in the first breeding season and weaning lighter calves.¹⁰ Reproductive performance in subsequent years was not different among these different heifer groups. Any potential decrease in reproductive performance in these heifers must be weighed against lower feed costs. These cost savings have been documented to range from $22 to $45 per heifer compared with dry lot development.