THE FLORIDA CATTLEMAN AND LIVESTOCK JOURNAL
Metabolic Imprinting: Nutrition during calfhood influences future growth and reproductive performance of dairy and beef calves**
|Dr. Philipe Moriel completed his PhD program at the UF/IFAS, Range Cattle REC in August, 2013. He is now an Assistant Professor of Animal Science at North Carolina State University. During his time at UF, Philipe focused on the impacts of metabolic imprinting on subsequent performance of beef calves. This research effort originated from a growing body of science aimed at understanding the effects of nutrition during early stages of life on subsequent human health and animal production. Data from human epidemiologic studies suggest that postnatal nutrition affects the risk for developing adult obesity, type 2 diabetes, hypertension and heart disease (Lucas, 1991). Such events occur because organ development, in most mammalian species, is not complete at birth and continues in the immediate postnatal period.|
Thus, nutrition during early-postnatal life may permanently change the physiology and metabolism of the organism, and have long-term consequences for the animal. This process was called “metabolic imprinting” (Lucas, 1991). The concept that metabolic imprinting may permanently affect animal development has economical implications for agriculture, and should be explored in order to improve the performance of animals destined for food production.
Early-weaned beef calves
At the Range Cattle REC, we early-wean calves from first-calf cows at 70 days of age. This practice improves the reproductive performance of primiparous beef cows, (Arthington and Kalmbacher, 2003), anticipates puberty achievement in heifers (Gasser et al., 2006), increases the growth performance of beef steers during the receiving feedlot period (Arthington et al., 2005), and enhances carcass quality of beef steers fed high-concentrate diets immediately following EW (Myers et al., 1999). However, many beef producers are unwilling to adopt this management practice due to a lack of information on the nutritional management of EW calves. Therefore, we evaluated different management systems for EW beef calves and their long-term consequences on calf performance in two experiments.
Experiment 1 evaluated the growth performance, carcass characteristics and muscle gene expression of beef steers, while experiment 2 evaluated the liver gene expression, growth and reproductive performance of beef heifers. In both experiments, calves were either normally weaned (NW) at 250 d of age (d 180 of the study), or early-weaned (EW) at 70 d of age (d 0) and randomly assigned to 1 of 3 calf management systems: 1) EW and grazed on ryegrass and bahiagrass pastures until d 180 (EWPAST); 2) EW and limit-fed a high-concentrate diet in drylot for at least 180 d (EW180); and 3) EW and limit-fed a high-concentrate diet in drylot for 90 d, then grazed on bahiagrass pastures until d 180 (EW90). Calves in drylot were limit-fed the high-concentrate diet at 3.5% of body weight (BW; as-fed), whereas EW calves on pasture were supplemented with the same high-concentrate diet at 1.0% of BW (as-fed).
Experiment 1 demonstrated that overall growth performance of EW steers was similar or greater than NW steers (Table 1) throughout the entire study. Early-weaned calves provided a high-concentrate diet in drylot for at least 90 d (EW90 and EW180 steers) were heavier at the time of NW and at shipping (d 260) compared to NW and EWPAST steers. However, early-exposure to high-concentrate diets did not affect the overall carcass characteristics and marbling scores of steers slaughtered at a common backfat thickness (Table 1). Of 13 studies comparing carcass characteristics of EW vs. NW steers, only half of the studies reported greater marbling scores for EW vs. NW steers. Reasons for the inconsistent results among those studies and experiment 1 may be attributed to the differences related to common end point at slaughter (BW, age or backfat thickness), breed, calf age at the start of the study, diet composition (e.g. starch concentration), timing and quantity of steroid implantation, and interaction among all of those factors. Nevertheless, nutrition during early stages of postnatal life has a large potential to influence the growth performance and carcass characteristics of beef steers, and deserves further evaluations.
Experiment 2 demonstrated that EW heifers limit-fed a high-concentrate diet for at least 90 d in drylot, and EW heifers grazed on pastures and supplemented with concentrate at 1% of BW for the entire study, had similar or greater growth performance than NW heifers (Table 2). From d 180 until the end of the breeding season (d 395), heifers were grouped by treatment and supplemented with concentrate at 1.5% of BW (as-fed). During this period, no differences were detected for average daily gain among treatments (1.52, 1.60, 1.36 and 1.54 ± 0.058 lb/d for NW, EWPAST, EW180 and EW90 heifers, respectively). Interestingly, limit-feeding a high-concentrate diet in drylot, for at least 90 d, increased the percentage of pubertal heifers at the start of the breeding season (d 335) compared to NW heifers (Table 2). Particularly, a greater percentage of EW90 heifers achieved puberty at the start of the breeding season, despite having similar BW and ADG from the time of NW until the end of the breeding season compared with NW heifers. This response indicates that early puberty attainment may be achieved if heifers are exposed to high-concentrate diets and high-growth rates at young ages (approximately 70 d of age). In addition, our data suggest that age at puberty decreased by nearly 58 d for every 1 lb increase on ADG of heifers from d 0 to 90 (70 to 160 d of age). Bos indicus-influenced heifers represent the majority of heifers in southern US, and often reach puberty at older ages compared to Bos taurus beef heifers. Thus, our results support the concept that puberty achievement of EW heifers was associated with a critical window (approximately 70 d following EW), in which enhanced nutrient intake and growth performance led to early-activation of the reproductive axis.
In summary, metabolic imprinting is the process by which nutrition, during early-life, may permanently affect the metabolism and performance of livestock. Early-exposure to high-concentrate diets to EW beef steers may enhance growth performance and carcass characteristics of beef steers, as well as, enhance the growth performance and anticipate puberty achievement of beef heifers. Thus, identifying strategies that are able to enhance calf performance, during early postnatal life, may provide unique opportunities to optimize feed resources and increase the profitability of dairy and beef cattle management systems.
** Portions of this article previously appeared in Feedstuffs. 2013. 85:12.
Arthington, J. D., and R. S. Kalmbacher. 2003. Effect of early weaning on the performance of three-year-old, first-calf beef heifers reared in the subtropics. J. Anim. Sci. 81:1136-1141.
Arthington, J. D., J. W. Spears, and D. C. Miller. 2005. The effect of early weaning on feedlot performance and measures of stress in beef calves. J. Anim. Sci. 83:933-939.
Gasser, C. L., D. E. Grum, M. L. Mussard, F. L. Fluharty, J. E. Kinder, and M. L. Day. 2006. Induction of precocious puberty in heifers I: enhanced secretion of luteinizing hormone. J. Anim. Sci. 84:2035-2041.
Lucas, A. 1991. Programming by early nutrition in man. Ciba Found. Symp.156:38-50.
Myers, S. E., D. B. Faulkner, F. A. Ireland, L. L. Berger, and D. F. Parrett. 1999. Production systems comparing early weaning to normal weaning with or without creep feeding for beef steers. J. Anim. Sci. 77:300-310.