Feeding cholesterol and tallow to young calves

Area of Science:

• Animal Nutrition
• Biochemistry
• Animal Husbandry

Background:

• Understanding the impact of dietary fat and cholesterol on young ruminants is crucial for optimizing calf growth and health.
• Holstein bull calves are a key model for studying nutritional interventions in beef production.

Purpose of the Study:

• To investigate the effects of dietary cholesterol and tallow supplementation on growth, plasma lipid profiles, and fat metabolism in young Holstein bull calves.
• To determine the influence of these additives on nutrient digestibility and meat quality.

Main Methods:

• Four groups of eight 4-week-old Holstein bull calves were fed distinct starter diets: control, 1% cholesterol, 5% tallow, or 1% cholesterol plus 5% tallow.
• Growth parameters (body weight, size, average daily gain) were monitored.
• Plasma lipid and cholesterol levels were analyzed.
• Chromic oxide was used to estimate nutrient digestibility, particularly fat digestibility.
• Organ weights and meat composition were assessed at 21 weeks of age.

Main Results:

• Dietary supplementation with 5% tallow reduced body weight, size, and average daily gain in calves.
• Both tallow and cholesterol significantly increased plasma lipids and cholesterol by 35-40%.
• Increased fat intake from tallow enhanced fat metabolism and excretion, but fat digestibility was lowest with cholesterol alone.
• No significant differences were observed in organ weights or meat composition at slaughter.

Conclusions:

• Dietary tallow negatively impacts growth performance in young Holstein bull calves.
• Cholesterol and tallow supplementation effectively alter plasma lipid profiles, indicating altered lipid metabolism.
• While tallow influences fat metabolism and excretion, cholesterol may impair fat digestibility.
• These findings suggest careful consideration of fat and cholesterol levels in calf starter diets for optimal growth and metabolic health.