Effects of replacing soy bean meal with poultry byproduct meal on performance, nutrient digestibility, excreted nitrogen and feeding behavior in Holstein lactating cows

This study was conducted to investigate the effect of soybean meal replacement with poultry byproduct meal on milk yield, nutrient digestibility, feeding behavior and excreted nitrogen in lactating cows 32 cows with 2 calving with average milk production of 33 ± 3.7 kg were used. This experiment was performed in a completely randomized design with four treatments and eight replications. Treatments included: control treatment (diet without poultry byproduct meal), second treatment (diet containing 33% substitution), third treatment (diet containing 67% substitution) and fourth treatment (diet containing 100% poultry byproduct meal replacement diet instead of soybean meal). The results of this experiment showed that, among the experimental treatments, there was a significant difference in dry matter intake, percentage of dry matter consumption in relation to body weight and body score, daily milk production, milk production efficiency, corrected milk based on milk fat, number and somatic cell score and milk pH were observed. But density, electrical conductivity and freezing point of milk were affected by experimental treatments. With increasing levels of poultry byproduct meal replacement with soybean meal, the percentage of these cases also increased (P<0.05). Nutrient digestibility, nutritional behavior and percentage and grams per liter of fecal nitrogen and fecal pH and urine were not affected by experimental treatments. According to the obtained results, soybean meal can be completely replaced by poultry byproduct meal, which is a source of animal protein, up to 10% of dietary dry matter.