By Kim Ricardo
Replacement heifers represent one of the largest annual investments in a cow-calf enterprise and are often developed using expensive stored feed and forages. In South Dakota, native range, crop residues, and annual forages can allow for heifers to be developed more economically in forage-based systems compared to traditional drylot environments without sacrificing reproductive performance.
Forage-based development systems offer a lower-cost alternative to drylot programs, but they require intentional management to ensure heifers reach adequate size and reproductive maturity before the breeding season. This article outlines how South Dakota producers can strategically use available forage resources to develop replacement heifers efficiently while maintaining long-term herd productivity and sustainability.
Development Goals
The primary objectives of any heifer development program should be to produce females that conceive early in their first breeding season, calve unassisted, and remain productive members of the cow herd over multiple years. Traditional recommendations suggest developing heifers to 60 to 65% of mature body weight by the start of their first breeding season (Patterson et al., 2000). This guideline is supported by foundational research demonstrating that endocrine mechanisms responsible for puberty are suppressed until heifers achieve sufficient body size and composition to support reproduction (Rawlings et al., 2003).
More recent research, however, indicates that well-managed heifers can achieve comparable pregnancy rates when developed to lighter target rates of 50 to 55% of mature body weight, particularly when compensatory gain occurs prior to breeding (Funston et al., 2012). These findings are especially relevant for forage-based development systems, where nutrient supply can vary seasonally and input costs are closely managed.
Consistency of gain, also known as average daily gain (ADG), during development plays a significant influence on timing of puberty attainment. Research demonstrates that moderate growth rates, rather than rapid growth early on, are sufficient for acceptable reproductive performance, providing heifers ultimately reach their target body weigh prior to breeding.
Source : sdstate.edu