Effects of adding pomegranate peel to diets containing different fatty acid sources on nutrients intake and chewing behavior of primiparous Holstein cows

Primiparous cows are generally more sensitive to low pH, higher concentrations of volatile fatty acids, and postpartum ruminal acidosis than multiparous cows, possibly due to differences in feeding patterns and variation in nutrient intake. The aim of this study was to evaluate the ratio of omega-6 and omega-3 fatty acids in diets with or without pomegranate peel as a rich source of antioxidants, on nutrient intake, chewing behavior, and sorting activity of primiparous Holstein cows.

Primiparous Holstein cows (n = 12) were randomly divided into a Latin square design with a 2 × 2 factorial arrangement of treatments. Each period lasted 28 days with 21 days of adaptation to the diet and 7 days for data collection and sampling. The diet (1.5% dry matter) contained calcium salts of fish oil (CAFO) or palmitic acid-enriched fat (PAF) with (+ PP, 8.7% dry matter) or without (-PP) pomegranate peel.

Fats and nonstructural carbohydrate intakes were greater in palmitic acid-enriched fat -fed cows thancalcium salts of fish oil -fed cows. Also, intake of dry matter, energy, organic matter, protein, neutral detergent fiber, nonstructural carbohydrate and fats in cows supplemented with +PP diets were greater than cows fed –PP diets. Consumption of particles retained on 8-mm sieve, pan, peNDF8 in cows on +PP diets were greater than those in -PP cows. Cows fed palmitic acid-enriched fat treatment had less rumination time per kg of neutral detergent fiber, peNDF8 and peNDF1.18 than calcium salts of fish oil -fed cows. Also, palmitic acid-enriched fat treated cows had less chewing time per kg of peNDF8 and peNDF1.18 than cows in calcium salts of fish oil treatments. Sorting activity against long particle and peNDF1.18 and in favor of medium particle were higher in cows fed –PP diets than those in cows fed +PP treatments. Eating meal number per day increased and time between meals and duration of each meal decreased in –PP-fed cows than those in +PP-fed cows. Rumination and chewing time per kg of peNDF1.18 intakes were greater in –PP cows than +PP cows.

Under the conditions of this experiment and in primiparous cows, palmitic acid-enriched fat -fed cows had less chewing and rumination times per kg of peNDF intake than calcium salts of fish oil treatment however, the sorting activity and chewing pattern were not affected. Pomegranate peel increased nutrients intake, reduced sorting against long portions and fiber, as well as reduced the meals number and increased the duration of each meal.