Effect of a Phytogenic Feed Additive in Preventing Calves' Diarrhea

Growth Performance, Health Parameters, and Blood Metabolites of Dairy Calves Supplemented with a Polyherbal Phytogenic Additive

This study aimed to evaluate the effects of dietary supplementation with increasing levels of a polyherbal phytogenic additive (PPA) on growth performance, health parameters, and blood metabolites of dairy calves. Forty female Holstein calves (43.35 ± 2.41 kg body weight and 25.1 ± 2.2 d of age) were housed in individual pens and randomly assigned to four treatments (n = 10) with increasing levels of PPA: 0 (CON), 2 (PPA2), 3 (PPA3), and 4 (PPA4) g PPA/d for 67 d. Compared to the CON treatment, supplementation with the PPA2 treatment increased (quadratic effect p = 0.02) the average daily gain and final body weight of the dairy calves. Also, a higher starter intake (SI), and intake of milk + milk replacer was observed (linear and quadratic effect p = 0.0001) in response to supplementation with the PPA2, PPA3, and PPA4 treatments. The evaluated treatments did not affect (p > 0.05) the feed conversion ratio, or the number of cases of diarrhea, pneumonia, and otitis. The evaluated treatments did not affect (p > 0.05) most of the hematological and biochemical blood parameters. However, compared to the CON treatment, supplementation with the PPA2 treatment increased (quadratic effect p < 0.05) the blood concentration of the segmented neutrophils and plasma protein. Likewise, the serum glucose concentration decreased (linear effect p < 0.05) with supplementation of the PPA2, PPA3, and PPA4 treatments. Compared with the CON treatment, the PPA4 supplementation decreased the serum urea concentration (linear effect p = 0.04). In conclusion, supplementation with 2 g/d of PPA can be used as a natural alternative to improve the growth rate and stimulate starter and milk + milk replacer intake in dairy calves without adverse effects on health parameters or blood metabolites.

Effect of Dietary Supplementation of Chestnut and Quebracho Tannin Supplementation on Neonatal Diarrhoea in Preweaning Calves

Neonatal calf diarrhoea (NCD) poses a significant health challenge in cattle herds, resulting in considerable economic losses and antimicrobial use. In response to the escalating threat of antimicrobial resistance, viable alternatives are imperative, aligning with European policies. This study evaluated the in-milk supplementation of the chestnut and quebracho tannin extract in preweaning calves on performance, diarrhoea occurrence, Cryptosporidium spp. shedding, protein digestibility, and intestinal health. Twenty newborn calves were divided, after colostrum administration, into two experimental groups for 30 days as follows: the control (CTRL) was fed with whole milk and solid feed, and tannins (TAN) were fed whole milk supplemented with 6/g day of tannin extract and solid feed. Faecal samples were collected on days 0, 3, 7, 14, and 30 for the evaluation of Cryptosporidium oocyst shedding and protein digestibility. Faecal consistency was evaluated during the sampling using the faecal score scale (0-3 scale, considering diarrhoea > 1). The results showed a significant reduction in diarrhoea frequency in the TAN compared to the CTRL group (p < 0.05) over 30 days of the trial. The prevalence of Cryptosporidium spp. was generally low (12%), considering all analysed samples. Protein digestibility revealed comparable values for the TAN and CTRL groups, suggesting that tannins did not negatively affect milk protein availability. In conclusion, the in-milk supplementation of 6/g day of the chestnut and quebracho tannin extract could be considered a valuable functional feed additive to decrease NCD occurrence, thus supporting animal health and decreasing antibiotic use in livestock.