Department of Fundamental Sciences in Animal Husbandry, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 2 October 2023; accepted for publication 21 Movember 2023)
Abstract. The present experiment aimed to compare the effect of the physical form of a starter for dairy replacement calves on some rumen fermentation parameters. Nine male calves 4 days old and averaging 41.3 kg (SD = 3.6) were divided into three groups. The calves were housed in individual hutches bedded with straw. The calves were weaned at the age of 56 days of age and remained in the experiment until they reached 70 days. Three different physical forms of starter feeds were tested: 1) Ground starter – starter in meal form with coarsely ground maize (GS); 2) Pelleted starter (PS); and 3) Textured starter – a mixture of whole maize grain plus pelleted protein concentrate (TS). The ingredients and chemical composition of the three starter feeds were similar. The calves from all groups received 4 L of whole milk until 56 days of age. The liquid feed was provided twice daily from 4 to 35 days of age, and once daily from 36 to 56 days. From 35 days of age, calves were offered a free choice of alfalfa hay. OM digestibility was lower in calves that received ground starter compared to calves fed pelleted starter and textured starter. Apparent total tract digestibility of CP was the lowest in calves fed GS compared to those receiving PS and TS (P <0.05). No statistically significant difference in CP digestibility was observed between PS and TS-fed calves. EE digestibility was significantly lower in calves that received GS compared to those that received PS (P <0.05), but not different from EE digestibility in calves fed TS. The highest EE digestibility was that in PS-fed calves. CF digestibility was the highest in calves that received PS and the lowest in those fed GS, with significant differences (P <0.05). There was no significant difference in NFE digestibility among tested physical forms of starter feeds.