Clinical signs and bone changes associated with phosphorus deficiency in beef cattle

Area of Science:

• Veterinary Medicine
• Animal Nutrition
• Ruminant Physiology

Background:

• Phosphorus is an essential mineral for skeletal development and maintenance in cattle.
• Dietary phosphorus requirements vary with age, physiological state, and production level.
• Long-term effects of suboptimal phosphorus intake on adult cattle bone health are not fully elucidated.

Purpose of the Study:

• To investigate the long-term effects of varying dietary phosphorus levels on skeletal integrity in Hereford cows.
• To characterize the clinical and pathological manifestations of phosphorus deficiency in cattle.

Main Methods:

• A 10-year feeding trial with 42 Hereford cows, individually fed diets with controlled phosphorus content.
• Dietary phosphorus levels were manipulated across different life stages, including growth, gestation, and senescence.
• Clinical observations, radiography, and bone histopathology were used to assess skeletal health.

Main Results:

• Cows fed diets with less than 6 g of phosphorus/day developed a syndrome including weight loss, rough hair, abnormal stance, and lameness.
• Spontaneous fractures of vertebrae, pelvis, and ribs were observed in deficient cows.
• Bone demineralization, osteoporosis, cortical thinning, and impaired mineralization of osteoid tissue were evident radiographically and histopathologically.

Conclusions:

• Sustained low dietary phosphorus intake leads to significant skeletal pathology in mature cattle.
• Inadequate phosphorus availability results in excessive bone turnover, structural compromise, and functional impairment.
• Maintaining adequate phosphorus levels is crucial for preventing bone disease and ensuring the longevity of beef cattle.