Cattle reproduction

Farmed animals tend to be subjected to compounds that can be classified more easily as drugs. In some cases, animals may encounter compounds in nature that have considerable limitations in inclusion in the diets of farmed animals. An example is the inclusion of zearalenone (Figure 1) and its derivatives in animal diets these have anabolic and oestrogenic properties " and are permitted to be used in some areas of the world but are prohibited from use in others, such as European Union countries. Thus this compound and its reduced isomers (zearalenols, zeranols) improve growth rates in animals but can cause reproductive problems, especially in pigs. Ralgro, which is a commercially prepared derivative of zearalenone, is used as an ear implant in beef cattle as a growth promoter in... 

One of the earliest cattle problems involved widespread poisoning of cattle by arsenic at the turn of the century. Abnormal intake of arsenic results in severe colic (salivation, thirst, vomiting), diarrhea, bloody feces, and a garliclike odor on the breath cirrhosis of the liver and spleen as well as reproductive effects may be noted. Arsenic trioxide in the feed must be approximately 10 mg/kg body weight for these effects to occur. 

This technology is most often applied to valuable animals (e.g. prize winning horses, or high milk-yield dairy cattle) in order to boost their effective reproductive capacity several-fold. All the offspring will inherit its genetic complement from the biological mother (and father), irrespective of what recipient animal carries it to term. 

Co deficit Everywhere Low content of Co in Podsoluvisols, Podzols, Arenosols and Histosols. The average Co content in plant species is < 5 ppb The decrease of Co content in tissues decrease of vitamin BJ2 in liver (tr.—130 ppm), in tissue (tr.—0.05 ppm), in milk (tr.—3 ppm). Synthesis of vitamin Bi2 and protein is weakened. Cobalt-deficiency and Bj2 vitamin-deficiency. The number of animal diseases is decreasing in raw sheep —cattle — pigs and horses. Low meat and wool productivity and reproduction... 

Mimosine toxicoses include hair loss in horses, cattle, and laboratory animals and fleece loss in sheep. Cataracts and reproductive problems have also been reported in rodent models. Prolonged ingestion of Leucaena by cattle in northern Australia resulted in low weight gains, hair loss and goiter. 

L.B. Willett and C.P. Hodgson of Ohio State University, in collaboration with the U.S. Department of Agriculture, are currently investigating reproductive, metabolic, and nutritional disorders following heptachlor exposure from contaminated food in cattle (FEDRIP 1990). These investigators will also determine the cellular alterations that can influence reproductive or other homeostatic mechanisms. 

Vitamin E, a natural antioxidant, is essential for growth, disease prevention, tissue integrity and reproduction in all fauna. Natural vitamin E, as it occurs in plants, consists mainly of a-tocopherol (III, R = H) with minor amounts of y-tocopherol (IV), although this ratio can vary as for example in the vegetable oil composition shown in Fig. 5a. In animal husbandry, such as dairy farms or cattle feed lots, the stock diets are commonly supplemented with vitamin E, because processed grain-based cereal fodder, hay, and silage are deficient in vitamin This results in higher levels of a-tocopherol... 

Two female sex hormones, estradiol-17 and progesterone, and one male sex hormone, testosterone, are used as growth promoters on beef cattle (Fig. 7.1). By nature, they are all endogenous products playing an important role in controlling reproductive functions in humans and animals. When applied exogenously they will enter the same metabolic pathways as the endogenously produced molecules. 

In livestock and laboratory animals, a deficiency of vitamin E substances may cause degeneration of reproductive tissues, muscular dystrophy, encephalomalacia, and liver necrosis. Considerable research is required to fully determine supplementation of livestock diets unless typical symptoms of a deficiency appear. Symptoms have appeared where there are selenium deficiencies in the soil and where there are excessive levels of nitrates in the soil. White muscle 1 is the term used to describe a condition of muscular dystrophy in cattle. 

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