Folic acid or folate is a B-complex vitamin that works as a donor and acceptor of one‐carbon units. Thus, it is involved in the synthesis of nucleic acids (DNA) and amino acids (methionine). The name folic acid is deduced from folium (leaf in Latin), because this vitamin was originally isolated from spinach leaves.
Bovine leukosis (BL) is a lifelong disease of dairy cattle caused by the bovine leukosis virus. Although most infections appear to be subclinical, a proportion of cows over 3 years old (30 – 50%) develop persistent lymphocytosis, and a smaller percentage (5%) develop malignant tumors (lymphosarcomas) in various internal organs.
The use of cactus for feeding dairy cows in dry areas has been increasing mainly due to its high efficiency of water use, rapid dissemination, high water and energy content, and high forage yield. Opuntia stricta is a large cactus originated in central America that can grow up to two meters in height.
Sugar beet is a temperate climate crop grown mainly for production of sucrose. Beet pulp, the main co-product obtained during the process, is a common ingredient in dairy cow diets. Beet pulp is a good nonforage fiber source with high levels of digestible fiber and pectic substances.
Soybean meal, canola meal, and corn distillers’ grains are good sources of protein for dairy cows. Since they have different rumen undegradable protein (RUP) content and amino acid profile, feeding diets that include two or three protein sources is the best strategy for covering amino acids requirements in high producing cows.
Faba beans (Vicia faba) is a grain legume that may be considered as dual-purpose feed for protein and starch contents. Due to its high protein (28 – 32% dry matter; DM) and starch contents (40% DM), faba beans can replace both protein meals and cereal grains in dairy cow diets.
Synthetic flavors are additives used in the animal feed industry to enhance the smell and taste of feeds. The sense of taste in dairy cattle is well developed. They can recognize the five basic tastes of sweet, bitter, salty, sour, and umami. Therefore, identifying flavor preferences of dairy calves may help to stimulate and improve the consumption of calf starter.
Selenium is an essential trace mineral that is an indispensable component of the antioxidant system. Selenium is an essential element of antioxidant enzymes such as glutathione peroxidase, and its deficiency may result in an imbalance of redox homeostasis and ultimately oxidative stress.
Berry fruits contain vitamins (C, E, folic acid) and other biologically active substances such as tannins, saponins, flavonoids, phenolic acids… that may be beneficial for ruminants. These substances can potentially stimulate the microbial metabolism in the rumen and improve fermentation of nutrients.
Whey is a coproduct of the cheese or casein manufacture used as an animal feed supplement. Despite its high energy density, its usage is limited in high production cows due to the low protein content in proportion to the salt and lactose content.