Abstract
The article presents the results of a production trial aimed at assessing the effect of two sugar-containing feed components on the productivity of Holstein-Friesian cows. The study was carried out in two dairy farms in Northern Kazakhstan: JSC Astana-Onim and LLP En-Dala. The first farm used a mineral lick block containing sugar, macro- and microelements and vitamins, while the second farm used grain molasses at a dose of 4.0 L per cow per day. Control and experimental groups were formed by the analogue method, taking into account age, live weight, milk yield and milk fat content. Milk productivity was evaluated by lactation periods, and feed intake, digestibility, live weight dynamics, service period and economic indicators were also considered. The inclusion of sugar-containing components increased milk yield for the whole lactation in both farms: from 6,277.7 to 7,500.0 kg in JSC Astana-Onim and from 5,314.0 to 5,964.7 kg in LLP En-Dala. The most pronounced response was recorded during the first 100 days of lactation, when cows have the highest demand for readily fermentable carbohydrates. Experimental groups also showed improved feed intake, digestibility and dry matter use efficiency. Economic efficiency increased by 15.5% and 11.6%, respectively. At the same time, prolonged use of grain molasses in late lactation requires dose adjustment and control of effective fiber in the diet. Further studies should include statistical testing, milk composition analysis and evaluation of optimal sugar-to-protein ratios under different feeding systems.