Effects of multi-strains yeast supplementation on health and performances in male Holstein calves

none3noIntroduction. Use of antibiotics in livestock production has become a sensitive issue due to the reported cases of antibiotic resistance to pathogens in humans [1]. A correct and specific diet in beef cattle breeding cycle plays a key role to grant a better health and welfare of the animals [2]. The use of yeasts (Saccharomyces cerevisiae, in particular) in the diet of livestock animals, it is now a well-established practice [3, 4] and the positive effects obtained are known [5]. Animals, materials and methods. The objective of this study was to evaluate the health and the performances of young male dairy calves (17±3d) after S. cerevisiae and C. jadinii fractions product supplementation. At a commercial farm, 158 veal calves were enrolled and divided in two groups balanced for live weight: a control group (CTR) 57 animals (no supplementation) and a treated one (TRT) 101 animals (multi-strains yeast supplementation). Both groups were fed with a mixture of milk replacer (chemical composition %: CP 19, EE 17, ash 8) from 400 to 2600g/h/d in 4-16L/h/d, and grain mix with chopped straw (chemical composition %: CP 13.5, EE 3.2, CF 8.2, ash 4.1, DM 88) from 100 to 3500g/h/d. For TRT multi-strains yeast was added in the milk replacer: 5g/h/d during the first 30d, then 3g/h/d until d90. The diet was the same for both groups from d90 to 190 (slaughter). For all animals, mortality, morbidity (veterinary treatments) and individual carcass weights were collected. Blood parameters (Hg, RDW, MCV; d30, 73, 115, 150) and electrophoresis for blood protein characterization (d47, 118) were analysed in 23 randomly selected animals (12 CTR and 11 TRT). On sampled animals, body weights were measured (d0, 47, 82). All data were subjected to AOV procedure then T-test when significant differences were detected. Results and discussion. Health of calves was improved, but no difference was observed in mortality. Morbidity was reduced from 56% in CTR to 38% in TRT (P<.05), with a reduction of number of chronic animals (≥2 treatments per animal) by 50% (P<.05, table 1). Numerically, the reduction of veterinary treatments was mainly due to reduction of enteric treatments in TRT (-26%). Sampled animals’ ADG was impacted. ADG in TRT was 263g/d and 321g/d higher than in CRT (P<.01) from d0 to 47 and 47 to 82 respectively. Total carcass weight was numerically higher in TRT (+3.4%) than in CTR. Content of total proteins was higher in TRT (P<.01), with higher percentage of γ-globulins (P<.01) and higher percentage of α1-globulins (P<.01). These analyses are in favour of a better activated immune system of veal calves in TRT. No differences were observed on RDW and MCV. No differences in Hg average concentration, but more homogeneity in TRT. Table 1. Therapies carried out during the trial. CTR TRT P % healthy calves (0 treatment) 43.9b 63.4a <.05 % animals treated once 26.3a 21.8a % animals treated twice or more (chronic) 29.8a 14.9b Conclusion. This study demonstrates that the addition of multi-strains yeast supplement in the milk replacer during the first 90d of the lifecycle improved the health of veal calves. These results are in line with reduction in use of antimicrobial treatments in farms. References: [1] Langford et al. (2003) J. Dairy Sci. 86:3963-3966; [2] Heinrichs et al. (2011) J. Dairy Sci. 94:336-341; [3] Alugongo et al. (2017) J. Dairy Sci. 100:1189-1199; [4] Xiao et al. (2019) Animals. 9:4; [5] Robinson et al. (2009) Anim. Feed Sci. Technol. 149:185-98.nonePollesel M., Cavallini D., Tassinari M.Pollesel M., Cavallini D., Tassinari M