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This article presents a review describing the main mycotoxins encountered in pig feed which have a negative impact on sow fertility and reproduction. Consumption of feed that is contaminated with these mycotoxins may cause a variety of symptoms, depending on the type of mycotoxin, quantity and duration of exposure, as well as the health status and condition of the animal at the time of exposure. Two types of fungi are recognized, field fungi and storage fungi. Field fungi such as Fusarium spp., Aspergillus spp. and Claviceps spp. may produce toxins that lead to disturbed reproductive performance. Storage fungi occur if the humidity during storage is too high. In daily practice, the symptoms related to mycotoxicosis can occur at toxin concentrations below the detection limit. Mycotoxins may still be present in feedstuffs despite negative analytical findings and because of the presence of hot spots in feedstuffs. Clinical symptoms can be very pronounced or vague. The main toxins causing reproductive failure discussed in this article are aflatoxins, ergot alkaloids, trichothecenes and zearalenone.

Gonadotropin-releasing hormone in Cyprinidae as in other vertebrates functions as a brain signal which stimulates the secretion of luteinizing hormone from the pituitary gland. Two forms of gonadotropin-releasing hormone have been identified in cyprinids, chicken gonadotropin-releasing hormone II and salmon gonadotropin-releasing hormone. Hypophysiotropic functions are fulfilled mainly by salmon gonadotropin-releasing hormone. The only known factor having an inhibitory effect on LH secretion in the family Cyprinidae is dopamine. Most cyprinids reared under controlled conditions exhibit signs of reproductive dysfunction, which is manifested in the failure to undergo final oocyte maturation and ovulation. In captivity a disruption of endogenous gonadotropin-releasing hormone stimulation occurs and sequentially that of luteinizing hormone. In addition to the methods based on the application of exogenous gonadotropins, the usage of a method functioning on the basis of hypothalamic control of final oocyte maturation and ovulation has become popular. The replacement of natural gonadotropin-releasing hormones with chemically synthesized gonadotropin-releasing hormone analogues characterized by amino acid substitutions at positions sensitive to enzymatic degradation has resulted in a centuple increase in the effectiveness of luteinizing hormone secretion induction. Combining gonadotropin-releasing hormone analogues with dopamine inhibitory factors have made it possible to develop an extremely effective agent which is necessary for the successful artificial reproduction of cyprinids.

Muscle, egg and blood samples from female sea-run Baltic salmon from Dalälven were analyzed for neutral and phenol-type organohalogen substances (OHS) to determine their potential associations to the M74 syndrome of wild Baltic salmon. No differences in the concentrations of DDT and related compounds, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), or methoxylated brominated diphenyl ethers (MeO-PBDEs) in healthy salmon compared to salmon that produced offspring with M74 were observed. A large number of phenol-type compounds (> 100), such as polyhalogenated (brominated and/or chlorinated) phenols, polychlorobiphenylols (OH-PCBs) and OH-PBDEs were identified or indicated. High blood concentrations of PCP were found in both healthy salmon and in salmon that produced offspring with M74. Both hydroxylated and methoxylated PBDEs, in concentrations similar to the PBDE congeners, were found. 2-(2′,4′-dibromophenoxy)-4,6-dibromoanisol and the corresponding phenol were identified in the salmon samples. During the spawning period different concentration ratios of the OHS were indicated between muscle, egg, and blood plasma lipids depending on the individual OHS. No differences in OHS concentrations were observed between healthy salmon and salmon that produced offspring with M74. Consequently, the data do not support the theory that the M74 disease is induced by OHS. However, the relation between the disease and phenol type OHS must be further considered since the data available on levels of these compounds are still limited.

Early mortality syndrome or EMS that affects salmonids in the Great Lakes exhibits many of the same clinical signs as Cayuga syndrome, that affects Atlantic salmon (Salmo salar) in the New York Finger Lakes and the M74 syndrome that affects Atlantic salmon from the Baltic Sea. These similarities may reflect their shared characteristics of associated low thiamine concentrations in eggs and therapeutic responsiveness to exogenous thiamine treatment. When egg thiamine levels fall below a species-specific threshold clinical signs include loss of equilibrium, depression of respiration and reduced heart rate. Although feeding studies with thiamine deficient diets have yet to confirm a thiamine cause-effect relationship, EMS-like symptoms can be induced with thiamine antagonists. Patterns of temporal variability of EMS among Great Lakes' salmonids over the last 3 decades have been similar. In coho salmon (Oncorhynchus kisutch), EMS was negatively correlated with alewife (Alosa pseudoharengus) abundance in Lake Michigan. We hypothesize that this may reflect quantitative or qualitative change in the alewives eaten because despite their fluctuating abundance they have remained the preferred diet item. The limited data available for other salmonids suggest similar trends.

The aim of this study was to evaluate the effect of raising the rear end when replacing the prolapsed uterus in cows on the outcome and reproductive performance. A total of 76 cows with uterine prolapse were investigated, 10 of which had died before treatment. According to the posture, cows were divided into standing (n = 11) and recumbent (n = 55). Recumbent cows were subdivided randomly into lying (n = 24), lifting up using a cow-lift (n = 18), and raising hind legs using a tractor (n = 13). Recovery rate after treatment of all cows was 60.6%. The recovery rate of recumbent cows (52.7%) was significantly lower than that of standing cows (100%). Lying cows showed the lowest recovery rate (37.5%), which was significantly lower than the recovery rate (64.5%) of the combined cow-lift and raising groups. The mean nonpregnant term of raising animals (144 days) was significantly shorter than of cow-lift animals (297 days). In conclusion, the method of replacing the uterus by raising the hind legs during treatment of uterine prolapse in cows could improve the recovery rate and breeding performance.

Mummification of the bovine foetus is rare in cows. There is currently limited data available on the success of pregnancies following expulsion of mummified foetuses, especially after expulsion of twin mummified foetuses. This report describes a case of the expulsion of twin mummified foetuses from the uterus two days apart and the process of oestrous synchronisation for a new pregnancy of a five-year-old Holstein Friesian cow. The patient was referred with a slimy chocolate-coloured vaginal discharge. Bone fragments directly related to the foetus were visualised using transrectal ultrasonography with no foetal fluid in the uterus. An intramuscular single dose of prostaglandin F2alpha (PGF2alpha) analogue was given to the cow and antibiotic therapy was started. On the second day of treatment a mummified foetus was seen in the vagina, while another mummified foetus was observed by transrectal ultrasonography in the uterus. Therefore, a PGF2alpha analogue was re-injected and the second foetus was expelled 58 h later. When the cow showed oestrous behaviour, the vaginal discharge was cloudy and intrauterine treatment was applied. A pregnancy was achieved in the next oestrus. It is suggested that after expulsion of the foetus, the uterus should be lavaged and gynaecological examinations should continue until the patient has normal ovarian and uterine activity.

Research within the Swedish FiRe project Reproductive Disturbances in Baltic Fish has focused mainly on the M74 syndrome, which has caused high mortality in fry of sea-run Atlantic salmon (Salmo salar) from the Baltic Sea. At the end of the 4-year project, the cause of M74 is still not known, but the symptoms have been well described and treatment with thiamine (vitamin B1) has been found to cure afflicted fry. The M74 syndrome shows great similarities to Early Mortality Syndrome (EMS) in salmonids from the North American Great Lakes. Both M74 and EMS are characterized by a diet-related deficiency of thiamine in fry and broodstocks. A combination of factors may contribute to M74, e.g. the diet of salmon in the Baltic Sea, the content of thiamine or thiaminase (an enzyme that degrades thiamine) in their prey fish, ecological changes in Baltic Sea food chains, and pollutants. The few remaining wild, naturally spawning populations of Baltic salmon are at great risk of extinction, as there is no practical method of treating them with thiamine to prevent M74, and they are subject to heavy fishing pressure in the Baltic Sea. A reproductive disturbance similar to M74 occurs in Baltic sea trout (S. trutta), although at lower frequencies than in salmon. The M74 syndrome does not occur in Baltic cod (Gadus morhua), whose reproductive success is impaired mainly by poor oxygen conditions in its deepwater spawning grounds, in combination with heavy fishing pressure on large cod.

Most Baltic salmon populations are affected by the M74 syndrome, which has been linked to the feeding ecology of sea-run fish. A 2-year study in 1995-1997 showed that sprat (Sprattus sprattus) dominated the salmon diet in the Baltic proper (45-90% of the stomach content by weight), followed by herring (Clupea harengus, 9-39%) and three-spined stickleback (Gasterosteus aculeatus, 0-14%). These figures are similar to those recorded in the early 1960s. There was a consistent tendency for sprat to make up a higher proportion of the diet in the winter from January to April, and later in the year the proportion of herring and sticklebacks increased. When comparing the eastern and southern parts of the Baltic proper, there was also a tendency in the eastern part in January-September for the diet to have a lower proportion of sprat and a higher proportion of herring. This difference was, however, not significant according to the more conservative of 2 different statistical tests. There were also indications that wintertime feeding by salmon had increased compared with the early 1960s. In a regression study, the incidence of M74 was found to be strongly correlated to several parameters that describe the status of the Baltic sprat stock, two of which were weights of sprat. This suggests that the analysis of factors influencing the development of M74 needs to be expanded to include lower trophic levels as well.

A total of 48 repeat breeder cows were equally divided in to two treatment groups as NOR and NOR-PG and were treated with norgestomet ear implants on day 10 following natural oestrus and a control group. At the time of ear implant insertion, 2 ml of SMB injection was administered intramuscularly to all the cows. The implant was removed after 9 days. Cows in NOR-PG group were injected with 0.98 mg of PGF2a at the time of implant removal. In NOR and NOR-PG groups, AI was done at 48 and 72 hours of implant withdrawal. In control group, cows were artificially inseminated twice at 24 hours interval during natural oestrus. Blood samples were collected at the time of implant insertion and withdrawal in all the treated cows for progesterone assay. There was 100 per cent oestrus response following implant removal in NOR and NOR-PG groups. The conception rate obtain in NOR, NOR-PG and control groups were 43.75, 37.50 and 18.75 per cent, respectively. The overall mean level of progesterone (6.31±0.32 ng/ml) noticed at the time of implant insertion was significantly reduced to a lower level (1.38±0.16 ng/ml) by the time of its removal in treated cows. It is inferred that norgestomet_oestradiol alone without PGF2a may be used to augment fertility in repeat breeder cows under field conditions.