**4.2 Assisted reproduction techniques**

352 A Bird's-Eye View of Veterinary Medicine

can also be taken by cytology brushes (65 cm, 4 mm Ø) protected by a sterile metal tube (50 cm, 5 mm Ø). Endometrial cytology is a practical technique to diagnose subclinical endometritis, when clinical signs are absent. The number of neutrophils indicates the type

**4. Therapy and control of RBC syndrome to reduce the negative impact on** 

To reduce the negative effects of repeat breeding on the farm profitability, an effective therapy must be established after a proper diagnosis. Nutritional supplements have been used to restore certain imbalances at herd level. The assisted reproductive techniques, such as in vitro production or embryo transfer, have provided new therapeutic options for resolving this syndrome. Alternative medicines have also developed protocols to overcome the syndrome, as moxibustion or acuapunture. However, hormonal treatments, with progestins, GnRH, exogenous gonadotrophins and prostaglandins, have been traditionally

As previously mentioned, RBC syndrome causes considerable economical losses in beef and dairy cattle associated to reproductive failure, drop in milk yield and calves, and treatment cost. Numerous treatments have been studied to solve and prevent this syndrome at herd or

Nutritional deficiencies have been described as causes of RBC. Diets containing higher concentration of inorganic iodine from 8-12 days before estrus improve the stimulation of the pituitary gland, reducing at the same time the RBC rate (McDonald et al., 1961). Herds with problems of repeated estrus were supplemented with copper and magnesium, minimizing fertility problems (Ingraham et al., 1987). Deficiencies of these minerals have been associated with infertility, anemia or immune suppression. Concentrations of these minerals can be modified in the diet as a result of the season or agriculture practices, or as a consequence of mineral availability alteration associated with some dietary components (e.g. diets containing high level of protein reduce the copper plasma concentration). Betacarotene, precursor of vitamin A, has recently been investigated for its involvement in the formation and function of CL. Although no conclusive results exist, it is suggested that betacarotene improves the progesterone synthesis and reduces the luteal hypofunction (Wang et al., 1988). Further experiments are required in order to assert its therapeutic role or positive effect on reproduction. In 1992, Marai et al. reported that repetitive administration of 40 g/animal/day of sodium phosphate monobasic (in diet) plus 500 ppm zinc (in water) improves the fertility. Deficiencies of phosphorus and zinc are linked to low levels of progesterone, which could be the cause of failures in fertilization or early embryonic death. Other consequences associated with deficient diets are hypoglycemia, reduced coenzyme NAD (important for progesterone synthesis), decreased carbohydrate concentration or increased creatinine. Unsaturated fatty acid diets improve the milk yield and embryo development rates when administered at dry and postpartum periods, also being beneficial

and grade of endometrial inflammation.

**farm profitability** 

used.

individual level.

in RBCs.

**4.1 Nutritional treatments** 

Abnormal implantation and transport of gametes are associated with endometrial defects, resulting in RBC syndrome. Certain assisted reproduction techniques, as in vitro production of embryos or intraperitoneal insemination, have been proposed to solve this syndrome.

Intraperitoneal insemination could be an alternative procedure to the normal deposition of semen in the genital tract of the cow (Lopez-Gatius, 1995). It is considered that between 36 and 89% of RBCs show uterine diseases but are often difficult to detect in field conditions. A bypass from vagina to peritoneal area (around the ovary) is possible to avoid the negative effects of altered uterine environment on the sperm quality (Figure 6).

Fig. 6. Intraperitoneal insemination.

Other authors (Tanaka et al., 1994) consider that the majority of embryonic abnormalities occur in the oviducts, but are not apparent until 6-7 days post-breeding. Then, oocytes of RBCs are competent to reach the blastocyst stage. IVM, IVF, IVC and ET techniques are proposed to improve the reproductive success in these animals.
