I.  INTRODUCTION

Background

Growth and development impact all components of meat and milk production. Feed consumption is a primary regulator of growth and development.  Tissues and biological systems must undergo coordinated developmental changes to form a mature end-product. Growth and development of the fetus and early neonatal animal have lasting effects on health, performance, and productivity.  The manner in which muscle and mammary tissue grows and develops dictates the quantity and quality of meat production, as well as the efficiency of how  feed energy is converted to a final food product.  Growth and development of adipose tissue impact carcass composition, meat quality, and mammary development.  Turnover of mammary epitholium during lactation impacts persistency of lactation.

Vision Statement

Optimize growth and development to enhanced production efficiency and product quality.

Mission Statement

We seek to improve conversion of feeds to animal products; increase rate of production of animal products; and improve composition of animal products.

Impact

Livestock and poultry management systems that promote efficient production and products that promote human satisfaction, health, and well-being.

Linkages

USDA-ARS National Programs: 103 Animal Health; 105 Animal Well_Being and Stress Control Systems; 107 Human Nutrition; and 207 Integrated Agricultural Systems.

Other Agencies and Departments: NADDK, Brigham Young University, Purdue University, University of Maryland, and University of Wyoming.

Private Sector:  US-Israel Binational Agriculture Research and Development Fund, Finn Feads, Fund for Rural America, NRI-Grant, Pfizer Animal Health, Alpharma, Inc., and GroPep, Inc.

II. PROBLEMS TO BE ADDRESSED

Regulating feed intake

Problem of Statement

A major controlling factor of growth across species is feed intake.  Feed costs represent the primary economic input into livestock production systems.  Metabolic and sensory factors affect short-term feeding behavior.  Long-term feeding behavior is controlled by the animal in its attempt to achieve a defined equilibrium within its environment.  Understanding mechanisms involved in regulating feeding behavior and appetite may lead to more efficient production of livestock and poultry.

Goals

 1. Regulate intake to optimize use of feed resources

 2. Improve energy balance of neonatal livestock and poultry

Approaches

1. Elucidate roles of nutritional metabolites and hormones in regulating feed intake.

2. Identify hypothalamic factors that control systems regulating feed intake.

3. Identify physiological processes controlling neonatal feed intake and their interactions with stressors.

 Outcomes

1. Improved efficiency of feed use by livestock and poultry.

2. Increased neonatal survival rates.

ARS Locations

Clay Center, NE; Athens, GA; Beltsville, MD; Dubois, ID; East Lansing, MI.

Tissue growth and development

Problem Statement

Rapid and efficient growth is important for profitable animal production.  Under market conditions with small profit margins for livestock and poultry producers, improved growth and efficiency is critical for economic survival of many producers.  Optimum growth, performance, and efficiency have limited value if product quality is not acceptable to consumers.  The impact of tissue development and growth on meat tenderness and composition is not understood.  Knowledge of genetic factors and nutrition that control development and growth of muscle, fat, and mammary tissue is needed to develop practical methods for improving meat quality and composition and milk production.  

Goals

1. Alleviate physiological and environmental conditions to enhance expression of growth potential by livestock and poultry.

2. Alter characteristics of meat products from livestock and poultry to improve palatability and nutritional value.

3.  Determine the genetic and physiological basis for replication and differentiation of adipocyte precursor cells, muscle satellite cells, and mammary epithelical stem cells.

4.  Identify tissue specific bioregulatory mechanisms for adipose, bone, muscle, and mammary tissue growth, and function.

Approaches

1. Investigate neural, endocrine, and immune mechanisms affecting growth and composition at animal and tissue levels.

2. Use whole-animal and in vitro models to understand and control developmental processes as they affect productivity and product quality.

3. Characterize growth- and immune- related endocrine function during tissue wasting that accompany parasitism and endotoxemia.

4. Manipulate differentiation of fat cells from fetal stromal vascular cells.

Outcome

1. Increased growth rate and reduced length of production cycles in the livestock and poultry industries.

2. Livestock and poultry products with sensory attributes and nutrient composition desired by consumers.

3.  Increased lactational persistency and efficiency of milk production in dairy cattle.

ARS Locations

Clay Center, NE; Athens, GA; Beltsville, MD; Dubois, ID; East Lansing, MI.