The influence of high planes of nutrition on skeletal growth and development of weanling horses.

This research investigates how providing young horses with excessively high nutrition levels affects their bone growth and development. The study identifies that while high nutrition does enhance weight gain and growth of long bones, it may compromise other aspects of skeletal development.

Study Overview

• The researchers conducted two separate experiments involving weanling horses being fed various grain-based diets, each with different levels of nutrients.
• The nutrient levels were dictated by the National Research Council’s (NRC) recommended levels for growth, along with various elevated levels of digestible energy (DE), Protein (CP), and Calcium (Ca).
• Across the two experiments, five different groups were studied; a control group (Ctl) that received nutrients at NRC recommended levels, and four other groups that received 150% of their DE requirement, along with other differing levels of CP and Ca.

Experiment 1 Results

• The group referred to as HE received 150% of their DE requirement and demonstrated a significant increase in body weight (BW) and total cortical width (the outer shell of bone).
• The group named LC (low calcium) received 150% of DE and only 35% of Ca requirements and showed reduced gains in third metacarpal length (a major bone in a horse’s foreleg) and lower radiographic bone density than the control group.

Experiment 2 Results

• The HEP group, which received 150% of DE and 275% of Protein requirements, saw significantly larger increases in body weight, wither height (the ridge between the shoulder blades), and third metatarsal length (a major bone in a horse’s hindleg).
• The HEPC group, which was given 150% of DE, 275% of Protein, and 500% of Calcium requirements also grew significantly larger than the control group in body weight and wither height.

Conclusions

• The results from the two experiments suggest that higher planes of nutrition result in faster body weight gains and more significant growth of several long bones in young horses.
• However, it was observed that such high nutrition levels might compromise skeletal development, particularly in the area of the cortical bone – a crucial aspect for structural strength and integrity in horses.