Effects of a blend of essential oils in milk replacer on performance, rumen fermentation, blood parameters, and health scores of dairy heifers

Holstein calves fed a milk replacer with a direct fed microbial (DFM) and a starter containing a botanical extract or a DFM alone or in combination

Botanical extracts (BE; Apex, Adisseo, North America) have demonstrated enhanced DMI and improved gut health, while direct fed microbials (DFM), such as Lactobacillus acidophilus fermentation product (EX: Excell, Pacer Technology, Inc.), has demonstrated improved gut health and growth performance of growing Holstein calves. The hypothesis was this combination may be synergistic to neonatal calf growth performance and intestinal health. Eighty, 2-5-d old Holstein bull calves were blocked by BW and randomly assigned to one of 8 treatments arranged in a 2 × 4 factorial using a randomized complete block design. The main factors were milk replacer (MR) without (Control) and with EX added at 5 g/d fed and calf starter (CS). The CS containing no additives (Control); CS containing BE at 496 mg/kg; CS containing EX at 2.50 g/kg; and CS containing BE and EX at the same inclusion rates. The MR were fed 2x/d at 0630 and 1800 h along with free choice CS (amounts and orts weighed d) and water. Weaning occurred after d 42 for the 56-d experiment. No MR by CS main effects interactions were detected for BW, ADG, CS intake, total DMI, feed efficiency or body frame gain parameters. The BW gain (38.0 and 39.3 kg for control and EX, respectively) for MR main effect was similar for calves fed both MR, while CS main effects (38.7, 39.7, 39.2, and 37.2 kg for control, BE, EX, and BE&EX, respectively) was similar among all CS. Gains in body length (10.6 and 10.8 cm), hip width (4.5 and 4.5 cm), withers height, (10.5 and 10.6 cm) heart girth (18.6 and 19.9 cm) and body length (9.1 and 7.9 cm) were similar for calves fed both MR, while CS main effects for hip height (10.5, 10.2, 10.3, and 10.9 cm), hip width (4.7, 4.6, 4.4, and 4.3 cm) withers height (10.7, 10.9, 10.3 and 10.6 cm), heart girth (19.9, 18.9, 18.9, and 19.4 cm), and body length (11.7, 9.1, 8.3, and 8.4 cm) were similar. Total days of a fecal score = 0 was greater for calves fed Control MR and BE CS compared with calves fed Contol MR and the combination of BE&EX with calves fed the remaining treatments being intermediated and similar. This study demonstrated little calf growth performance and health benefits when feeding a BE or EX alone or in combination compared with calves fed control.

Essential oil blend supplementation in the milk replacer of dairy calves: Performance and health

Supplementation of dairy calves with essential oils in the liquid diet can reduce the incidence and severity of infectious diseases and promote better performance. Our objective was to evaluate an essential oil blend containing peppermint, eucalyptus, and menthol crystals and its effect on performance and health during the pre and postweaning period of dairy calves. At birth, 40 dairy calves (34 males and 6 females) were blocked according to sex and birth weight, randomly assigned to one of two treatments-commercial milk replacer diluted at 14% (MR) and the same liquid diet plus essential oil blend (MREO) at a dose of 4 mL per calf per day, divided into two meals during the first 28 days of life. Calves were individually housed and fed 6 L/d of the liquid diet, divided into two meals, and received starter concentrate and water ad libitum. Weaning was gradually reduced by 1L per day at d 51 until complete weaning at 56 days. After weaning, calves were evaluated until 70 days of age, when the experimental period ended. Intake, fecal, and health scores were evaluated daily, weight and body measures were recorded weekly, and blood parameters were evaluated at weeks 1, 2, 3, 4, and 8. Calves fed MREO tended to have higher total dry matter intake during the preweaning period. Furthermore, MREO calves had lower health scores and fewer days with a health score ≥ 4 (suggestive of bronchopneumonia), tended to lower coughing days and fewer veterinary interventions preweaning, and tended to lower health scores postweaning. The supplementation with a blend of essential oils containing peppermint, eucalyptus, and menthol crystals can reduce respiratory problems. Further studies are needed to investigate the dose and the supplementation period.

Potential benefits of a blend of essential oils on metabolism, digestibility, organ development and gene expression of dairy calves

The objective of this study was to evaluate blood cells and metabolites, insulin-like growth factor-1 (IGF-1), digestibility, internal organs weight and histology, gene expression, and spleen cell proliferation of pre-weaned bull calves supplemented with a blend of essential oils in milk replacer (MR). Sixteen newborn Holstein × Gyr crossbred dairy bull calves, with body weight at birth of 33.3 ± 3.7 kg, were housed in individual sand bedded pens, blocked by genetic composition, and randomly assigned to 1 of 2 treatments in a randomized complete block design: Control (CON, n = 8) and blend of essential oils supplementation (BEO, n = 8, 1 g/day/calf, Apex Calf, Adisseo, China). The commercial blend was composed by plant extracts derived from anise, cinnamon, garlic, rosemary, and thyme. Animals were fed 5 L of MR/day reconstituted at 15% (dry matter basis), divided into two equal meals. Water and starter were provided ad libitum. ß-hydroxybutyrate, urea, and glucose were evaluated weekly, IGF-1 was evaluated biweekly, and total blood cell count was performed every four weeks until the end of the trial at eight weeks of age. Feed samples were collected three times a week and polled for weekly analysis. Apparent total nutrient digestibility was determined from d 56 to 60 of age. On d 60 ± 1, animals were euthanized for organ weight, histology, spleen cell proliferation, and intestinal gene expression analysis. Data were analyzed independently using linear mixed models using the REML method in the nlme package in R for continuous outcomes. A non-parametric test was used for ordered categorical outcomes using the Artools package in R. There were no differences between groups for blood evaluations, digestibility, gene expression, and a spleen cell proliferation assay. However, BEO calves presented a heavier pancreas, heavier intestines, bigger ileum villi, and higher cecum butyrate levels (P < 0.05), demonstrating that the EO supplementation helped intestinal development and symbiotic bacteria. It was also observed in CON animals' heavier respiratory tract and a higher eosinophil count (P < 0.05). Therefore, the organs where eosinophils are more active had a better response for BEO animals. No differences were found in the intestinal gene expression in the immune context. These results demonstrate that supplementing essential oils in MR could contribute to gut development and immune function. However, more research is needed to understand its impact on body development and define the best dosage and route of administration.

Fecal microbiota dynamics and its relationship to diarrhea and health in dairy calves

BACKGROUND

Diarrhea is a major cause of morbidity and mortality in young calves, resulting in considerable economic loss for dairy farms. To determine if some gut microbes might have resistance to dysbiotic process with calf diarrhea by dictating the microbial co-occurrence patterns from birth to post-weaning, we examined the dynamic development of the gut microbiota and diarrhea status using two animal trials, with the first trial having 14 Holstein dairy calves whose fecal samples were collected 18 times over 78 d from birth to 15 d post-weaning and the second trial having 43 Holstein dairy calves whose fecal samples were collected daily from 8 to 18 days of age corresponding to the first diarrhea peak of trial 1.

RESULTS

Metataxonomic analysis of the fecal microbiota showed that the development of gut microbiota had three age periods with birth and weaning as the separatrices. Two diarrhea peaks were observed during the transition of the three age periods. Fusobacteriaceae was identified as a diarrhea-associated taxon both in the early stage and during weaning, and Clostridium_sensu_stricto_1 was another increased genus among diarrheic calves in the early stage. In the neonatal calves, Prevotella_2 (ASV4 and ASV26), Prevotella_9 (ASV43), and Alloprevotella (ASV14) were negatively associated with Clostridium_sensu_stricto_1 (ASV48), the keystone taxa of the diarrhea-phase module. During weaning, unclassified Muribaculaceae (ASV28 and ASV44), UBA1819 (ASV151), Barnesiella (ASV497), and Ruminococcaceae_UCG-005 (ASV254) were identified being associated with non-diarrheic status, and they aggregated in the non-diarrhea module of co-occurrence patterns wherein unclassified Muribaculaceae (ASV28) and Barnesiella (ASV497) had a direct negative relationship with the members of the diarrhea module.

CONCLUSIONS

Taken together, our results suggest that the dynamic successions of calf gut microbiota and the interactions among some bacteria could influence calf diarrhea, and some species of Prevotella might be the core microbiota in both neonatal and weaning calves, while species of Muribaculaceae might be the core microbiota in weaning calves for preventing calf diarrhea. Some ASVs affiliated with Prevotella_2 (ASV4 and ASV26), Prevotella_9 (ASV43), Alloprevotella (AVS14), unclassified Muribaculaceae (ASV28 and ASV44), UBA1819 (ASV151), Ruminococcaceae_UCG-005 (ASV254), and Barnesiella (ASV497) might be proper probiotics for preventing calf diarrhea whereas Clostridium_sensu_stricto_1 (ASV48) might be the biomarker for diarrhea risk in specific commercial farms.

Different methods of eubiotic feed additive provision affect the health, performance, fermentation, and metabolic status of dairy calves during the preweaning period

Background

This study aimed to evaluate whether different methods of providing eubiotic feed additives to neonatal calves, during the preweaning period, can improve the calves’ health, performance, ruminal fermentation, and metabolic status. Forty-four (3-day-old) Holstein–Friesian dairy calves (22 female and 22 male) were divided into four treatment groups for the duration of the 8-week trial. The eubiotic feed additive consisted of a combination of probiotic Lactobacillus spp. (multiple-strains at a dose of 250 mg/calf/day) and phytobiotics containing rosmarinic acid, as the main bioactive compound (at a dose of 50 mg/calf/day). The groups were named: CON (control, without eubiotic in either the milk replacer or the starter feed), MR (eubiotic in the milk replacer), SF (eubiotic in the starter feed), MRS (eubiotic in both the milk replacer and the starter feed). The individual intake of starter feed and the fecal scores were measured daily, and body weight and biometric measurements were taken weekly until calves were 56 days of age. Blood samples were collected on day 3 and then every 14 days to determine concentrations of insulin-like-growth-factor-I, β-hydroxybutyrate, non-esterified fatty acids, and blood urea nitrogen. Ruminal fluid was collected on days 28 and 56 for short-chain fatty acids, NH₃-N, and pH measurements.

Results

The body weight of the calves of the MR treatment group was higher compared to all other groups on days 28 and 56. Including the eubiotic feed additive in the milk replacer increased average daily gain, starter intake, and total dry matter intake from day 29 to day 56 and the overall experimental period compared to the CON group. The calves with MR treatment had lower fecal scores from days 3 to 28, a number of parasite oocysts/cysts per gram of feces on day 28, and the occurrences of fecal consistency scores of 3 (mild diarrhea) and 4 (severe diarrhea) were 3.2 and 3.0 times lower, respectively, compared with the CON group. The MR group had higher ruminal concentrations of short-chain-fatty-acids, propionate, and butyrate on day 56 than the CON group. Adding eubiotics into milk replacer resulted in the highest concentrations of blood insulin-like-growth-factor-I and β-hydroxybutyrate from days 29 to 56 and the overall experimental period.

Conclusion

The addition of eubiotic feed additives into the milk replacer can improve health, performance, ruminal fermentation, and biochemical blood indices in dairy calves during the preweaning period.

Blend of Essential Oils Supplemented Alone or Combined with Exogenous Amylase Compared with Virginiamycin Supplementation on Finishing Lambs: Performance, Dietary Energetics, Carcass Traits, and Nutrient Digestion

Simple Summary

Antibiotics have been extensively used as growth promoters in livestock, but current interests are focused on limiting the use of conventional antibiotics as feed additives in livestock production. Essential oil compounds belong to a “generally-recognized-as-safe” category of feed additives that may serve as alternatives to conventional antibiotics used as growth promoters. In this study, dietary supplementation of finishing lambs with essential oils alone, or combined with exogenous enzymes, improved dietary energy utilization and meat production in a manner comparable to that of the antibiotic virginiamycin.

Abstract

Two experiments were conducted to compare a supplemental blend of essential oils alone (EO) or combined with enzymes (EO + ENZ) versus virginiamycin (VM), on characteristics of growth performance (Exp. 1) and digestion (Exp. 2) in finishing lambs. Lambs were fed a high-energy finishing diet supplemented with: (1) no supplement (control); (2) 150 mg supplemental EO; (3) 150 mg supplemental EO plus 560 mg alpha-amylase (EO + ENZ); and 4) 25 mg VM. Compared with the control, growth performance response to EO and VM were similar, enhancing (5.7%, p < 0.05) feed efficiency and observed dietary net energy. Compared with control, supplementation with EO + ENZ tended (p = 0.09) to increase dry matter intake (6.8%), improving (p < 0.05) weight gain and feed efficiency (10.4 and 4.4%, respectively). Dietary energy utilization was greater (2.7%, p < 0.05) for EO and VM than EO + ENZ. Treatment effects on the carcass and visceral mass were small, but additive supplementation decreased (p ≤ 0.03) the relative weight of the intestines. There were no treatment effects on measures of digestion nor digestible energy of the diet. Supplemental EO may be an effective alternative to VM in high-energy finishing diets for feedlot lambs. Combination EO + ENZ may further enhance dry matter intake, promoting increased weight gain.