Assessing effects of dietary and milking frequency changes and injection of cabergoline during dry-off on hunger in dairy cows using 2 feed-thwarting tests

We investigated the single and combined effects of 2 feeding levels (normal lactation diet vs. energy-reduced diet, both fed for ad libitum intake) daily milking frequencies (twice once) during 1 wk before dry-off day (d 0), as well an intramuscular injection either a dopamine agonist (cabergoline; Velactis, Ceva Santé Animale; labeled use only with abrupt dry-off, e.g., no reduction in level or frequency last milking) saline after on d 0 motivation clinically healthy, loose-housed, pregnant, lactating Holstein cows. From 0, all cows were same dry-cow intake. Cows subjected to feed-thwarting tests, test home pen using their diets (test A: −6, −1, 1; 35 min when feed bins filled, but locked) another carried out adjacent which access concentrate provided familiar plastic box was blocked by wire-mesh lid B: −5 2). In A, we recorded how often attempted per min, whether vocalized 35-min period, latency within 300 s unlocked. B, approach boxes (the identical open small portion concentrate) 600 directed behaviors toward (number occurences/5 min). On −6 A), clear differences among treatments found. displayed higher probability vocalizing more than 50% quicker approximately 5× B), 60% behavior B) normal diet. Moreover, 75% −1 compared A). previously 40% Reducing level, day, resulted consistently increased motivation, interpreted sign hunger. No change frequency, singly reduced energy density, found 0. Whereas, 2, milked twice once daily. injected cabergoline more, showed lower saline-injected irrespective treatment The are not easily warrant further investigation. hunger perspective, reducing rather density seems be less negative management reduce milk production dry-off.