Related Experiment Videos
Production performance of beef cows raised on three different nutritionally controlled heifer development programs.
H C Freetly1, C L Ferrell, T G Jenkins
1USDA, ARS, US Meat Animal Research Center, Clay Center, NE 68933, USA. freetly@email.marc.usda.gov
Journal of Animal Science
|April 28, 2001
Summary
Altering post-weaning feed intake for heifers impacts their growth and calf survival. While heifers can still conceive and their calves grow well, severe nutrient limitation may reduce first-calf survival rates.
Area of Science:
- Animal Science
- Reproductive Biology
- Nutritional Physiology
Background:
- Heifer development strategies significantly influence reproductive performance and offspring outcomes.
- Timed nutrient limitation is a method to manage heifer growth and resource allocation.
- Understanding the impact of varying nutritional planes on primiparous heifers is crucial for optimizing herd productivity.
Purpose of the Study:
- To evaluate the performance of primiparous heifers subjected to three distinct post-weaning nutritional development strategies.
- To assess the effects of timed nutrient limitation on heifer growth, conception rates, calving performance, and calf survival.
- To determine if altered post-weaning growth patterns affect subsequent reproductive success and calf viability.
Main Methods:
- Two hundred eighty-two MARC III heifers were assigned to HIGH, MEDIUM, or LOW-HIGH nutrient intake treatments for 205 days post-weaning.
- Nutrient intake was controlled by offering different quantities of the same diet, measured in kcal Metabolizable Energy (ME) per unit of metabolic body weight.
- Heifer performance metrics including body weight, hip height, conception rates, calving ease, calf birth and weaning weights, and calf survival were monitored.
Main Results:
- Heifers in the HIGH nutrient intake group exhibited greater hip height and body weight at the start of breeding.
- Conception rates, age at parturition, and time to calving did not differ significantly among treatments.
- Calf birth and weaning weights were similar across all treatments, but calf survival was lower in the LOW-HIGH nutrient group compared to the MEDIUM group.
Conclusions:
- Post-weaning growth patterns in heifers can be modified through controlled nutrient intake without compromising conception rates or calf growth potential.
- Meeting minimal body weight and ensuring adequate growth before mating are key for heifer reproductive success.
- Limit-feeding strategies, particularly severe nutrient restriction, may negatively impact first-calf survival, necessitating careful monitoring of feed allocation to optimize resources.