Nutrition of Dairy Cows

Anotace: The aim of this study was to show the individual relationships between selected parameters within the groups of high-producing Holstein-Friesian dairy cows in the Early Lactation (EL), Peak Lactation Multiparous (PLM) and Peak Lactation Primiparous (PLP). Firstly, the relationship of individual fractions (Penn State Particle Separator (PSPS) method) retained on Pennsylvanian sieves on dairy cow activity - feed intake time/ eating time (ET); rumination time (RT); time no-active (TN) - was evaluated using BouMatic‘s RealTime Activity program. It was found that there was a statistically significant difference between the EL group, which intake less amount of fibre retained on the sieve with 8 mm hole size (46.90%) with the PLM (50.19%) and PLP (49.41%) groups (p <0.05). The decrease in fibre intake (8 mm) was related to the fraction intake retained per pad where there was a statistically significant difference between EL (28.02%) and PLP (25.69%); PLM (25.19%) group (p <0.05). The data obtained regarding ET and RT between the groups showed a statistically significant difference where low RT and ET was observed just at higher fraction intake per pad (28.02%) and lower fibre intake (46.90%) in the EL (4:16 h) group compared to PLM (4:41 h) and PLP (5:37 h) (p <0.05), where the percentage intake of fractions contained per pad was lower. The study also evaluated the effect and relationship between selected parameters (starch, lactic acid-LA, fermentation processes-FP, NH3 ,acid-detergent fibre-ADF, neutral-detergent fibre-NDF, pad, physically effective neutral-detergent fibre-peNDF) on ET and RT. The starch content of the total mix ration was in medium high negative correlation with RT (p <0.05) and on the other side the peNDF content was characterised by a strong positive correlation with RT (p <0.01). Based on these results, it was found that dairy cows in the EL group preferred a rather higher intake of fractions contained on the pad, which influences the reduced intake of particles retained on the 8 mm average sieve and thus their overall activity (ET, RT, TN) is influenced. Dairy cows in the PLM and PLP groups preferred a higher intake of fiber particles (8 mm) which influenced the increase in activity time (ET, RT).