PSIX-18 - Use of Feed Additives to Improve the Recovery of Unweaned Calves After Transportation

Abstract: Transportation of unweaned calves involves periods of feed restriction and stress without a fully developed immune system and gastrointestinal tract. The use of additives to enhance intake and immunity at arrival could be a strategy to minimize those negative effects. Holstein male calves (n + 39; 16 ± 1.2 d of age and 46 ± 0.1 kg of BW) were used to evaluate the effect of a mixture of feed additives (FA) comprising palatability enhancers, standardized olive pomace extract and tributyrin on performance, energy balance (BHBA), GI functionality (Cr-EDTA and citrulline) and inflammation in calves fed restrictively [2.5 L of milk replacer (MR) twice daily at 12.5%] simulating an assembly center and transported (fasted). Calves were distributed in 3 treatments: non-transported calves fed MR and concentrate without FA since the beginning of the study until weaning (CTR; n=13); and two treatments where calves were fed MR without FA during the restriction period (3d) and transported for 19 h, at arrival calves were offered MR and concentrate without FA (TNA; n =13) or with FA (TWA; n = 13). The MR was offered at 2.5 L twice daily and concentrate ad libitum. Data were analyzed with a mixed-effects model. After transportation (d0), calves on TNA and TWA treatments had a peak of concentrate intake greater (P < 0.05) compared with CTR even those calves had no concentrate before; and on d1, calves on TNA decreased concentrate intake in a greater extent than TWA. Serum IL-1ß on d1 was lesser (P < 0.05) in TNA compared with CTR and TWA. Serum citrulline on d 2 was lesser (P < 0.05) in the TNA compared with TWA. The mixture of FA mitigates the decline of concentrate intake the day after transport and seems to recover enterocytes mass estimated by serum citrulline concentration.