Research into the growth and development of Thoroughbreds managed on commercial breeding farms is reviewed in this paper. As horses are not meat producing animals, less research has been performed quantifying growth, muscle and bone development than with other production animals. However, variations in growth and development are linked with both value and wastage in young Thoroughbred horses, and can have a long-term impact on racing performance. In Thoroughbred horses, the breeder aims for optimum, or consistent, growth rather than maximum growth. Factors affecting equine growth including environment, nutrition, season and management are discussed in sections covering conception to weaning, weanling to yearling and yearling to 2 years old when horses are nearly fully grown and racing begins. The importance of reference curves for different ages, sex and locations is highlighted. While average daily gain (ADG) declines as the foal gets older, there are seasonal and management influences to consider. Month of birth has an influence on both birthweight and the expected ADG at different ages, which are believed to be related to ambient temperatures and pasture availability for the mare and growing horse. Weaning leads to a growth setback and ADG declines through winter, but increases in spring for the yearling as temperatures and pasture quality and quantity increase. Management factors such as yearling sale preparation are associated with an increase in growth rate, with gains of over 1 kg/day common during the yearling sales preparation process of 6–12 weeks. ‘Home-bred’ horses that do not go to a yearling sale grow at a slower rate but will reach the same endpoint in mature size. Growth of Thoroughbreds is influenced by country, and regions within a country, related to genetics, climate, management practices, market preferences and sale timing. More research is needed into factors affecting growth and development of Thoroughbred horses on commercial farms and the influence differing rates of growth and development have on wastage (such as developmental orthopaedic disease) and commercial outcomes such as yearling sale results and, ultimately, racing performance.

中文翻译：

---

纯种马的生长发育

本文综述了对商业养殖场管理的纯种马的生长和发育的研究。由于马不是产肉动物，与其他生产动物相比，对生长、肌肉和骨骼发育进行量化的研究较少。然而，生长和发育的变化与纯种马的价值和损耗有关，并且会对比赛表现产生长期影响。在纯种马中，饲养员的目标是最佳或一致的生长，而不是最大的生长。影响马匹生长的因素，包括环境、营养、季节和管理，将在涵盖从受孕到断奶、断奶到一岁马和一岁到两岁马匹几乎完全长大和比赛开始的章节中进行讨论。不同年龄参考曲线的重要性，性别和地点被突出显示。虽然平均日增重 (ADG) 随着小马驹长大而下降，但需要考虑季节性和管理影响。出生月份对出生体重和不同年龄的预期 ADG 都有影响，据信这与母马和成长中的马的环境温度和牧场可用性有关。断奶会导致生长受挫，ADG 会在整个冬季下降，但随着温度和牧场质量和数量的增加，一岁猪在春季会增加。一岁鸽销售准备等管理因素与生长速度的增加有关，在 6-12 周的一岁鸽销售准备过程中，增重通常超过 1 公斤/天。不参加一岁马销售的“国产”马匹生长速度较慢，但​​成年后的马匹会达到相同的终点。纯种马的生长受国家和国内地区的影响，与遗传、气候、管理实践、市场偏好和销售时间有关。需要对影响商业农场纯种马生长和发育的因素进行更多研究，以及不同生长和发育速率对浪费（如发育性骨科疾病）和商业结果（如一岁马销售结果以及最终的比赛表现）的影响。