Feeding fennel (Foeniculum vulgare) seed as potential appetite stimulant to newborn Holstein dairy calves: Effects on meal pattern, ingestive behavior, oro-sensorial preference, and feed sorting

Abstract

This trial was performed to investigate the effects of feeding graded levels of fennel seed powder (FSP) on nutrient intake, meal and rumination patterns, chewing and sorting behaviors in newborn Holstein dairy calves. Forty-eight calves (27 males and 21 females; n = 16 per treatment group; 3 d of age; 36.3 ± 1.06 kg of BW; mean ± SE) were assigned randomly to receive incremental levels of FSP at 0.0 (FSP0), 1.5 (FSP1.5) or 3.0 g/d (FSP3) in milk (morning feeding; during the first month of study period) and then in the starter feed (as top-dressed; from d 31 until weaning). Calves were weaned on d 71 and remained in the study until d 81. Starter feed dry matter (DM) intake increased linearly with increasing amount of FSP and increased and tended to increase in FSP3 and FSP1.5 as compared with FSP0, respectively. Growth rate increased linearly with increasing amount of FSP and was greater in FSP supplemented calves than in control calves. Overall body weight but not feed conversion ratio was greater in FSP supplemented calves compared with FSP0. Oro-sensorial preferences were greater in FSP supplemented calves and it was also greater in FSP3 compared with FSP1.5. Sorting index decreased linearly with increasing amount of FSP and decreased in FSP3 compared with FSP0 for particles retained on the 2.36, 1.18, and 0.6 mm sieves and tended to decrease in FSP1.5 compared to FSP0 for particles retained on the 2.36 and 1.18 mm sieves with significant difference for particles retained on the 0.6 mm sieve. Sorting index increased linearly with increasing amount of FSP and increased and tended to increase in FSP3 and FSP1.5 compared with FSP0 for feed materials retained on the bottom pan, respectively. Irrespective of the amount of FSP fed, all calves sorted for particles retained on all studied sieves and against feed materials on the bottom pan. Starter feed DM intake from particles retained on all studied sieves (except for 4.75 mm sieve) and feed materials retained on the bottom pan increased linearly with increasing amount of FSP and increased in FSP supplemented calves compared with control calves. Calves fed FSP initiated to eat their first solid feed in a shorter timeframe after starter feed provision with no changes in first meal duration among treatment groups. Despite of linear increase in eating rate and meal size in FSP supplemented calves, meal and rumination patterns and time devoted to eating, ruminating, resting, drinking, standing, and lying were not affected by treatment; however, non-nutritive oral behaviors were linearly decreased with increasing amount of FSP and decreased and tended to decrease in FSP3 and FSP1.5 compared with FSP0, respectively. In general, feeding FSP shortened time-delay to initiate first solid feed consumption by increasing oro-sensorial preference of the feed, increased feed intake through increases in the rate of eating and thereby the meal size, decreased non-nutritive oral behaviors without affecting chewing behavior, and improved growth performance.