MONITORING THE OCCURRENCE OF PATENS FORAMEN OVALE IN FATTENING SWINE BREEDS – CONTINUATION * PRA

The occurrence of foramen ovale patens (FOP) was investigated in 96 hearts taken from the Slovak meat-type (SM), 38 hearts from Yorkshire (YO), 51 hearts from Slovak meat-type x Yorkshire (SM x YO), 43 hearts from Pietrain x Yorkshire (PN x YO) and 45 hearts from Pietrain x Slovak meat-type (PN x SM) breeds. The investigation was done at the Station for Research and Meat Quality Evaluation. We determined the presence of FOP only in the hearts collected from SM in 7 cases, which is 13.7% of the occurrence, and in the PN x SM in 4 cases (11.2%). We did not observe any occurrence of FOP in the other investigated breeds. All of the investigated positive cases of FOP were in the male breeds of the SM. In the cross breeds of PN x SM two positive cases of FOP were found in both sexes. As far as the size of the FOP is concerned, there have been documented 2 mm diameter in four cases and 3 mm in three cases in the SM breeds. On the other hand, in the PN x SM cross breeds, neither case had more than 2 mm in size. After camparing these results with our previous work, we decided further to investigate the occurrence of these heart defects at the line level of each meat breed.

The occurrence of foramen ovale patens (FOP) was investigated in 96 hearts taken from the Slovak meat-type (SM), 38 hearts from Yorkshire (YO), 51 hearts from Slovak meat-type x Yorkshire (SM x YO), 43 hearts from Pietrain x Yorkshire (PN x YO) and 45 hearts from Pietrain x Slovak meat-type (PN x SM) breeds.The investigation was done at the Station for Research and Meat Quality Evaluation.
We determined the presence of FOP only in the hearts collected from SM in 7 cases, which is 13.7% of the occurrence, and in the PN x SM in 4 cases (11.2%).We did not observe any occurrence of FOP in the other investigated breeds.All of the investigated positive cases of FOP were in the male breeds of the SM.In the cross breeds of PN x SM two positive cases of FOP were found in both sexes.
As far as the size of the FOP is concerned, there have been documented 2 mm diameter in four cases and 3 mm in three cases in the SM breeds.On the other hand, in the PN x SM cross breeds, neither case had more than 2 mm in size.
After camparing these results with our previous work, we decided further to investigate the occurrence of these heart defects at the line level of each meat breed.
When we speak about the heart morphology defect, FOP, it will be better to characterize it at three levels: constant occurrence in some pig breeds and its absence in other breeds, the decrease of the utility of the meat breeds and the correction of a hereditary transmitted defect by means of breed line improvement Š4¹.Jelínek Š5¹ warned against the occurrence of this heart defect in Slovakia half a century ago.These characteristics have a negative impact on the economy of pork productions Š6¹ and this was confirmed in other research results Š3, 2, 1¹.
It is a pity that there has been no interest in this problem because no information source is available, even though the first warning work was published abroad Š7¹.
In Slovakia, where this work has been done, only a few researchers focused on the question of FOP in the pig Š6, 4¹.
From its prospective acute importance and being a topical problem which affects the health, production and economy, we devoted more time to this problem in meat breeds.We focused on the study of the transmission of this heart defect from breed to breed and the possibilities of decreasing or completely eliminating the occurrence of FOP from meat breed pigs.
The investigation was done at the Station for Research and Meat Quality Evaluation, which has its own slaughtering house.We looked into the hearts to find the presence of FOP after collecting them from the slaughtered pigs based on the constant method Š2¹.At the same time we also examined the size of the openings in all positive cases.
All documents of the fattening procedure at the station were available.
Our investigation was done on the following breeds.
The collected data of the results of the investigation are presentet in Table 1 and 2. From the 96 examined pig hearts in the SM, 7 cases were positive (13.7% of the total investigated animals).All seven defects were only in the female breeds.There were not any positive cases in 38 investigated hearts of the YO breed, 51 hearts from the SM x YO, and 43 hearts from PN x YO, but 4 cases in 45

Materials and methods / Materijal i metode rada
hearts from PN x SM breeds (11.2% of the total examined animals) were positive.The positive cases found were 2 in the female and 2 in the male (Table 1).

Ukupan broj pozitivnih slu~ajeva
Size of the foramen / Veli~ina foramena 2 mm diameter / pre~nik 2 mm 3 mm diameter / pre~nik 3 mm As far as the size of the openings are concerned (Table 2) in the SM, 4 cases from the seven positive ones were 2 mm in diameter (57.1%) and three cases were 3 mm (42.9%).In the cross breeds PN x SM all four positive cases were only 2 mm wide.
Due to the lack of reference sources on this problem we are able to compare the obtained results with our previous works on the FOP in different meat breed pigs.The results obtained from newly examined breeds are presented only as information and are evaluated as base values for further investigations.
Comparing the occurrence of FOP in SM, which showed 13.7% positive in this work, while the positive occurrence in the data of previous work, was only 3.3% Š1¹, it is easy to observe the big rise of this heart defect.It is interesting that all positive cases were found in male pigs only.
As far as YO breed is concerned, 2.7% occurrence of FOP Š1¹ was registered in the previous work, but in this work all these breeds were negative.
The other breeds: SM x YO, PN x YO and PN x SM were not examined because there were no positive cases presented in the previous work Š1¹ and this was confirmed in the work of Gabri{ et al.Š4¹, too.It is necessary to follow and observe the lines of the crossed breeds.This can be seen in the results of the cross breeds of PN x SM, where we found 2% occurrence of FOP with 2 mm in diameter.
Here, each breed used to cross might play the role to transform this heart defect.
The topic of the occurrence of FOP in meat breed pigs cannot be closed, but, on the contrary, it needs deep and wide research mainly at the level of lines of the commonly used breeds.

Table 1 .
The occurrence of foramen ovale patens in the observed breeds of swine Tabela 1. Pojava foramen ovale patens u posmatranim rasama svinja