The present review examines the factors and variables that should be considered to obtain, design, and evaluate EFEs that might enhance ruminal NDF degradability. Different combinations of words were introduced in Google Scholar, then scientific articles were examined and included if the reported factors and variables addressed the objective of this review. One-hundred-and-sixteen articles were included. The fungal strains and culture media used to grow white-rot fungi induced the production of specific isoforms of cellulases and xylanases; therefore, EFE products for ruminant feed applications should be obtained in cultures that include the high-fibrous forages used in the diets of those animals. Additionally, the temperature, pH, osmolarity conditions, and EFE synergisms and interactions with ruminal microbiota and endogenous fibrolytic enzymes should be considered. More consistent results have been observed in studies that correlate the cellulase-to-xylanase ratio with ruminant productive behavior. EFE protection (immobilization) allows researchers to obtain enzymatic products that may act under ruminal pH and temperature conditions. It is possible to generate multi-enzyme cocktails that act at different times, re-associate enzymes, and simulate natural protective structures such as cellulosomes. Some EFEs could consistently improve ruminal NDF degradability if we consider fungal cultures and ruminal environmental conditions variables, and include biotechnological tools that might be useful to design novel enzymatic products.

The objective was to review the potential effects of adding anthocyanin delphinidin-3-O-sambubioside (DOS) and cyanidin-3-O-sambubioside (COS) of HS in animal diets. One hundred and four scientific articles published before 2021 in clinics, pharmacology, nutrition, and animal production were included. The grains/concentrate, metabolic exigency, and caloric stress contribute to increasing the reactive oxygen species (ROS). COS and DOS have antioxidant, antibacterial, antiviral, and anthelmintic activities. In the rumen, anthocyanin might obtain interactions and/or synergisms with substrates, microorganisms, and enzymes which could affect the fiber degradability and decrease potential methane (CH₄) emissions; since anthocyanin interferes with ruminal fatty acids biohydrogenation (BH), they can increase the n-3 and n-6 polyunsaturated fatty acids (PUFA), linoleic acid (LA), and conjugated linoleic acid (CLA) in milk and meat, as well as improving their quality. Anthocyanins reduce plasma oxidation and can be deposited in milk and meat, increasing antioxidant activities. Therefore, the reduction of the oxidation of fats and proteins improves shelf-life. Although studies in ruminants are required, COS and DOS act as inhibitors of the angiotensin-converting enzyme (ACEi) and rennin expression, regulating the homeostatic control and possibly the milk yield and body weight. By-products of HS contain polyphenols as calyces with positive effects on the average daily gain and fat meat quality.

An experiment was carried out to evaluate the effect of spring and autumn seasons on the reproductive activity of Merino Socorro Island ewes and their crosses with Pelibuey under heat stress (HS) conditions in the tropics. All ewes (n = 80) were randomly assigned to one of two breeds during the first and second periods, respectively: (1) Twenty Socorro Island Merino ewes (SIM) and (2) 20 Pelibuey Crossbred ewes (PBC). Animals were fed the same diet and given water ad libitum. All statistical analyses were performed using SAS statistical software 9.12 procedures. In both seasons, a mean of more than 80 U of maximum THI was obtained, while in spring and autumn, the minimum THI exceeded 30 and 40 U, respectively. All animals were in oestrus and ovulated in both seasons. The frequency of animals in spring during the first 48 h of oestrus expression was greater (p < 0.05) than 48–55 h but similar (p > 0.05) than 55–65 h; in autumn during the first 48 h and 48–55 h were similar (p > 0.05), but different (p < 0.05) than 55–65 h. The duration of oestrus expression was longer in the spring than in the autumn (p < 0.05). The frequency of animals was higher (p < 0.05) in SIM than in PBC ewes during the first oestrus cycle (1–17 d) and was also higher (p < 0.05) in PBC than in SIM ewes during the second oestrus cycle (18–35 d). The SIM ewes produced more (p < 0.05) progesterone (P₄) than the PBC ewes. During the sampling days of the oestrus cycle, more P₄ was created in autumn than in spring (p < 0.05). Both breeds showed severe HS. In the future, ewes treated under assisted reproductive programs in the tropics may improve reproductive efficiency.

Sources of bias in genetic association studies of cattle: A review

The objective of this project was to evaluate the antimicrobial activity of essential oil (EO) emulsions in different types of meat challenged with Salmonella enterica subsp. enterica serotype Enteritidis (SE). Concentrations of 0.0%, 1.0%, 1.5%, and 2.0% of EO emulsions from eucalyptus (Eucalyptus globulus), lemon (Citrus limon), clove (Syzygium aromaticum), and oregano (Origanum vulgare) were prepared in chicken meat, beef, and pork inoculated with SE at 1-hour and 24 hours. The effectiveness of EO against SE in different types of meat showed the greatest bacterial reduction in beef and with the exposure time of 24 hours. The effectiveness of eucalyptus EO against bacterial growth was shown to be inferior compared to oregano, clove, and lemon EO. Therefore, the terpenoid carvacrol, the phenylpropene eugenol, and the terpene limonene demonstrated a greater reduction in SE survival than the 1.8-cineole in eucalyptus. In the interactions, oregano EO showed no differences in chicken meat but did show differences in beef at 1.0% and 1-hour exposure, compared to any concentration in chicken or pork at 1-hour and 24 hours exposure. Eucalyptus EO at 2.0%, 1-hour exposure, and in beef showed differences compared to any concentration in chicken for both exposure times. Increasing the concentration of lemon EO in chicken meat appeared to reduce its effectiveness against SE. Finally, clove EO showed its best results in beef at 1.5% and after 24 hours of exposure. It is recommended to conduct an experiment testing mixed oregano and clove EOs to enhance their bactericidal effect.

As part of a population health assessment of goats, a cross-sectional study with 356 goats (n=178 Alpine and 178 Saanen) was performed. A comparison was made between biochemical markers, hematological profile, composition of milk, somatic cell count, and milk fatty acid profile in Alpine and Saanen goats. The highest concentration of non-esterified fatty acids, triglycerides, urea, and alkaline phosphatase was found in Alpine goats. The lowest concentration of sodium ion and chloride ion was observed in Saanen goats. The concentration of glucose, total cholesterol, β-hydroxybutyrate, albumin, globulin, total protein, calcium ion, inorganic phosphate, potassium ion, magnesium ion, and γ-glutamyl transferase showed no breed difference. The red blood cell count, hematocrit, hemoglobin, mean cell volume, mean cell hemoglobin, mean cell hemoglobin concentration, white blood cell count, neutrophils, lymphocytes, monocytes, eosinophils, basophils, platelet count, and mean platelet volume showed no breed difference. Milk yield indicated that Saanen goats produced more milk. However, their milk fat and milk protein were lower compared to Alpine goats. Non-fat solids, density, cryometry, and pH showed no breed difference. The somatic cell count was higher in Alpine goats. The highest concentration of fatty acids was for palmitic and oleic. The highest concentration of butyric was observed in Saanen goats. However, their caprylic, capric, lauric, and myristic content was lower compared to those shown by Alpine goats. The concentration of caproic, myristoleic, palmitic, palmitelaidic, palmitoleic, stearic, elaidic, oleic, linolelaidic, linoleic, arachidonic, and behenic acids showed no breed difference. The results obtained can be used as reference values and influence the price paid by the Mexican goat dairy industry.