Effects of alternative protein sources from food industry byproducts in starter feeds on dairy calf growth performance under different conditions: a preliminary study

Dosmukhamed Muratov¹Bakhyt Kubekova¹Madina Khassanova¹Madina Smailova¹Doskali Naimanov¹Jan Miciński²Natalya Papusha^1*

• ¹NLC «Akhmet Baitursynuly Kostanay Regional University», Kostanay, Kazakhstan
• ²University of Warmia and Mazury in Olsztyn, Olsztyn, Warmian-Masurian, Poland

This study evaluated the effects of alternative protein sources from food industry byproducts in starter feeds on dairy calf growth and metabolism under different feeding conditions. Sixty Holstein × Black-and-White female calves were assigned to six groups across two farms: T1 (Starter A: 15% egg powder), T2 (Starter B: 15% feed yeast), and CON1 (standard starter) at Farm 1; T3 (Starter A), T4 (Starter B), and CON2 (standard starter) at Farm 2. Feed intake, body weight gain, feed conversion ratio (FCR), and blood biochemical parameters were monitored for 90 days. At Farm 1, T2 showed significantly higher weight gain (+3.47%, P = 0.01) and improved FCR (P = 0.03) compared to CON1. T2 also had increased total protein (P = 0.04) and ALP activity (P < 0.05), indicating better metabolic efficiency. At Farm 2, no significant differences in growth or FCR were found (P > 0.05), though T3 had higher total protein at 60 days (P = 0.04) and elevated GGT at 30 days (P = 0.02). Results suggest that food byproducts in starters improve feed efficiency but depend on feeding conditions. Further research is needed to assess the long-term impact on rumen development, nutrient digestibility, and immune function in dairy calves.