23 Feb 2024
Dairy calf nutrition: Inclusion of Essential Oils as Enhancers
Dairy calf nutrition: incorporating cinnamon, oregano, and eucalyptus essential oils as enhancers of health and performance
Before considering supplementing an animal’s diet, it’s crucial to grasp the fundamental nutritional requirements of the species. It’s established that the feeding regimen for calves commences with the intake of colostrum within the initial hours of life. Colostrum, aside from its nutritional content, furnishes the newborn with early immunity through defense cells, primarily immunoglobulins (CHASE et al., 2008), along with various other essential compounds.
Following the consumption of colostrum, calves transition to a liquid diet, which may consist of raw whole milk or alternatives. This liquid regimen serves as the primary nutrient source for calves, given that their intake of solid food is typically minimal during the initial stages of life, often failing to adequately meet their maintenance requirements.
When discussing milk alternatives, there are various options to consider, with the primary choice being milk replacer, essentially a powdered milk manufactured industrially.
The milk substitute contains various ingredients, including powdered milk and whey, and its primary advantage is its microbiological sterility and [register] easy storage, requiring only dilution in water before being supplied to the animals.
| Yet, a drawback of their utilization is that numerous options incorporate vegetable ingredients to heighten protein concentration and cost-effective carbohydrates, directly impacting calf development as their underdeveloped gastrointestinal tract struggles to digest certain components (BITTAR et al., 2018), like soybean meal, frequently employed for this objective. |
Alongside the liquid diet, calves should also receive a solid diet, primarily composed of concentrate with a high protein concentration to aid in development and growth. This concentration typically ranges from 22 to 26% and must consist of high-quality ingredients. As mentioned earlier, digestion capacity at this stage is not as efficient.
Once the basic nutritional requirements are met, it becomes possible to consider the provision of feed additives to enhance and stimulate the immune and antioxidant systems. This, in turn, leads to improved health and zootechnical performance, with the positive development during this phase directly influencing future performance.
As per Normative Instruction No. 44/15 issued by MAPA (Ministry of Agriculture, Livestock, and Supply), a food additive refers to any ingredient intentionally added to food products, not to fulfill nutritional requirements, but rather to enhance the food’s characteristics and/or improve animal performance in terms of zootechnical performance and health. Among these additives are essential oils, which are liquid and aromatic substances extracted from plant sources such as leaves, flowers, tree bark, seeds, and others (CUI et al., 2019).
Essential oils typically possess antioxidant, antimicrobial, immune-boosting properties, and above all, they enhance performance (CHAPMAN et al., 2016). Understanding the effects of each essential oil requires knowledge of its composition and the bioactive compounds present in its structure.
| Currently, the primary use of essential oils in ruminant nutrition is as a performance enhancer, due to their ability to modulate ruminal microbiota and consequently affect ruminal fermentation. |
As commonly understood, calves are non-ruminant animals at birth, as their ruminal system is underdeveloped both in function and size, and their development progresses over the subsequent weeks.
Considering this, the efficacy of using essential oils to modulate ruminal microbiota for enhancing the zootechnical performance of calves is limited during the initial weeks of life.
In this stage of animal development, essential oils primarily act as antioxidants and immune system boosters. This poses a challenge as calves are born without antibodies, and their immune system needs to be stimulated through colostrum intake and careful attention during the initial weeks of life.
Moreover, a major challenge in calf rearing is the prevalence of infectious diarrhea caused by pathogenic microorganisms in the intestinal microbiota. This condition leads to dehydration, reduced appetite, and consequent weight loss (CHO & YON et al., 2018), which, in severe instances, can result in the death of the animal.
Unfortunately, some diarrhea-causing bacteria have acquired a level of resistance to traditional antibiotics, requiring alternative interventions to mitigate the morbidity and mortality risks associated with these calves.
In this regard, feed additives, including essential oils, play a role. Due to their antimicrobial properties, they can modulate the intestinal microbiota, promoting beneficial microorganisms while reducing the presence of pathogenic microorganisms responsible for diarrhea and other clinical symptoms (JOUANY & MORGAVI, 2007).
This modulation is most effective when conducted in the early stages of life, before the microbiota stabilizes, making alterations more challenging (DILL-McFARLAND et al., 2018).
There is a strong relationship between the intestinal microbiota and the immune system. Immunoglobulin A (IgA), a crucial component of the humoral immune system, is found in the intestine as it is secreted by the mucosa. This helps maintain the normal and appropriate intestinal microbiota in calves (DU et al., 2023).
Apart from calves acquiring IgA through colostrum, in my master’s thesis, we observed that it can also be stimulated by cinnamon, oregano, and eucalyptus essential oils, which additionally reduced leukocyte and lymphocyte levels, benefiting the immune system.
Enhancing the intestinal microbiota and immune system of calves will make them healthier and more resilient. As a result, we can anticipate an enhancement in zootechnical performance, including increased weight gain and feed efficiency. This improvement is particularly advantageous for producers, as these outcomes become evident in their day-to-day operations.
Oils can be included through solid (concentrate) or liquid (milk and its substitutes) diets, and they can be in liquid form, diluted in an emulsifying vehicle, solid form as lyophilized, and when solid, they can be microencapsulated to allow them to pass intact through the rumen and be released only in the intestine, further acting on the intestinal microbiota.
 In Table 1, we can observe the essential oils highlighted in this article that were used in the nutrition of calves, including their inclusion in liquid and/or solid diets, their active principles, and their main results in the animal. |
Table1. Essential oils in the nutrition of dairy calves and their functions
Source: Adapted by the author based on the works of Ritt et al. (2021); Katsoulos et al. (2017); Selvi and Tapki (2019); Calsamiglia et al. (2007); Moo et al. (2021); Caldas et al. (2015); Cai et al. (2020); Volpato et al. (2019); Soltan (2009); Farshid et al. (2021); Liu et al. (2020).
Cinnamon, oregano, and eucalyptus oils have garnered considerable attention in scientific studies due to their myriad benefits, not only in calves but also across ruminants as a whole. Presently, essential oils also hold substantial prominence in the commercial arena, catering to both animal and human applications.
Companies specializing in animal nutrition additives are increasingly incorporating essential oils into their products and combining them with other additives that also offer health and zootechnical performance benefits.
| One significant benefit of using essential oils and other additives is their minimal inclusion in the diet due to their high potency. Therefore, despite their relatively higher acquisition cost, the overall expense is diluted. |
Given this, incorporating essential oils into the diet of calves, including cinnamon, oregano, and eucalyptus varieties, can serve as a beneficial alternative. This is because they enhance the two key aspects crucial for dairy calf rearing: health and performance.
Hence, essential oils offer a favorable alternative for enhancing the health and performance of future dairy cows on the rural farm.
References available upon request [/register]
