Simple SummaryIn grazing systems of temperate climate zones dairy cows are often fed with a silage- and concentrate-based diet during winter and are gradually introduced to a pasture-based diet in spring. This housing and feeding change involves many complex nutritional, behavioral, and metabolic adaptions, likely connected with alterations in energy metabolism. In a previous trial, feeding low amounts of concentrate during full-time grazing had not prevented energy shortage during the first weeks on a pasture system. Because of this, further research was needed to determine whether a higher concentrate supply during full-time grazing would have attenuated that energy deficit. In this experiment we were able to show that the transition period is connected with a higher activity due to walking and grazing, associated with changes in red blood cell count. Further parameters like lipomobilization, decreasing milk production, and loss in bodyweight confirm the alterations in energy metabolism. In summary, the present study shows the changes and its impact on the animals during transition to full-time grazing.AbstractIn spring, the transition from a total mixed ration (TMR) to pasture requires metabolic adaptions for the cow. It had been shown that supply of low amounts of concentrate after transition to full-time grazing caused energy deficits, resulting in a lower milking performance and changes in a variety of variables indicative for energy metabolism. The present study aimed to investigate how a moderate concentrate supply (4.5 kg dry matter cow/day) after transition to pasture influences health and production indicators. Over a 12-week trial period dairy cows were observed during transition from confinement to pasture (pasture group: PG) and compared to cows fed TMR indoors (confinement group: CG). On average, the PG consumed less feed and energy than the CG and mobilized body reserves, which is mirrored in a decrease of body condition and various fat depots. These effects were paralleled by elevated serum concentrations of non-esterified fatty acids and ketone bodies as well as an increase in liver fat content. The physical activity (elevated walking, eating, decreasing rumination time) of the PG was significantly higher than that of the CG, which intensified the energy deficiency and resulted in a lower milk yield. In conclusion, the moderate concentrate supply was insufficient to counterbalance the lower energy intake from pasture during transition.

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Objective: Prebiotics are used to support the gastrointestinal health via stimulating particular beneficial parts of the autochthonous microflora and enhancing their metabolism. Horses often suffer from gastrointestinal disturbances after feed changes or behavioral stress in response to transport. Therefore, the supplementation with prebiotic compounds might reduce the risk for intestinal dysregulation. The aim of this study was to investigate the influence of supplementation with Jerusalem artichoke meal (JAM) in a recommended prebiotic dosage on fermentation characteristics in the equine gastrointestinal tract.Methods: Twelve adult healthy horses received crushed oat grains (1.2 g starch/kg BW x d -1 ) and meadow hay (as fed basis; 1.5 kg/100 kg BW x d -1 ). Additionally, they were fed either an apparently prebiotic quantity of fructooligosaccharides (FOS) and inulin (0.2 g/kg BW x d -1 ) via Jerusalem artichoke meal (JAM) or an equal amount of maize cob meal without grains as control (CON) over 3 weeks. On d21, horses were euthanized, gastrointestinal contents were removed from 7 different regions of the gastrointestinal tract, the dry matter (DM) content, pH value and concentrations of short chain fatty acids (SCFA), L-and D-lactate and ammonia were measured.Results: JAM did not had a significant (P < 0.05) effect on any of the measured fermentation products and the pH value as well. Numerically, JAM increased the concentrations of SCFA (P > 0.05), lactate (both isomers, P > 0.05) and ammonia (P < 0.05) predominantly in the stomach but had no impact on the pH value overall. In the hindgut, the stimulation of the microbial activity was limited to the ventral colon only indicated by slightly higher SCFA (P > 0.05) and ammonia (P > 0.05) but lower L-lactate (P > 0.05) concentrations compared to control. Conclusion:FOS and inulin from JAM seem extensively be fermented already in the stomach of horses. The resulting organic acids might elevate the risk for gastric ulcers. Recently the gastric pH was buffered by concomitantly elevated ammonia, which requires a careful delineation of the influences of either individual acids or low pH levels or both together on the mucosa health in both distinct parts of the equine stomach. In the hindgut, the effect of JAM on the microbial activity seems to be much less pronounced than expected or advertised.

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