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

Abstract

Introduction: In today's society, where the price of food items is increasing, the use of
agricultural by-products, industrial factories and wastes from livestock and poultry
slaughterhouses and the dairy industry is very important in animal husbandry. Some byproducts
of food factories that are not usable for humans are valuable resources that can be
converted into valuable livestock products for use in animal feed. One of these by-products
is the waste powder of industrial poultry slaughterhouses, which is produced during the
production and processing of chicken meat.
Materials & Methods: 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).
Level of crude protein in all treatments was the same (16.2% of dry matter) and the
maximum consumption level of poultry byproduct meal in the diet was 10% of dry matter.
Result: 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 (P>0.05). But density (1.028 vs. 1.032; P=0.0171), electrical
conductivity (5.26 vs. 6.07; P=0.041) and freezing point of milk (-0.530 vs. -0.549;
P=0.083) 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 (P>0.05).
Conclusion: 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.