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Abstract Background Synesthesia is, as visual migraine aura, a common and fascinating perceptual phenomenon. Here we present a unique case with synesthesias exclusively during visual migraine auras. Case presentation A 40-year-old woman with a cyclic mood disorder had suffered from migraine with visual aura for several years. On several occasions she had experienced "mixing of senses" during the aura phase. Staring at strong bright light she could experience intense taste of lemon with flow from the salivary glands. Conclusion Acquired synesthesia, exclusively coincident with migraine aura, gives support to the idea of an anomalous cortical processing underlying the phenomenon.

In recent years, the development of new therapies and improvements in our understanding of older therapies have led to changes in the management of Parkinson's disease. However, current Norwegian and international therapy recommendations present a range of different options as being equally viable. In this clinical review, we propose an updated algorithm for the medical treatment of motor symptoms in Parkinson's disease, based on evidence-based recommendations and our own personal experience and opinions.

Background: Cancer is a major cause of death, but how cancer influences mortality risk in Multiple Sclerosis (MS) is unclear., Objectives: Determine all-cause mortality and mortality following a cancer diagnosis among MS patients compared with matched population controls., Methods: Norwegian MS patients born 1930 - 1979 (n= 6950) followed-up 1953 - 2016, were matched with 37 922 controls. We compared incident cancer diagnosis from the Cancer Registry of Norway, date of death from the Cause of Death Registry, education from the National Education Database, by multivariate Cox proportional hazard regression., Results: Hazard ratio (HR) and 95% confidence interval (CI) for all-cause mortality among MS patients was 4.97 (4.64 - 5.33), and 2.61 (2.29 - 2.98) for mortality following a cancer diagnosis. Mortality in MS was highest following urinary- (2.53: 1.55 - 4.14), colorectal- (2.14: 1.47 - 3.11), hematological- (1.76: 1.08 - 2.88), ovarian - 2.30 (1.73-3.06) and breast cancer diagnosis (2.61: 1.85 - 3.68), compared to controls. High education was inversely associated with mortality among MS patients., Conclusions: All-cause mortality was five- fold and mortality following a cancer diagnosis was two- fold increased among MS patients. Mortality following specific cancers raises the possibility of diagnostic neglect., Competing Interests: Competing interests The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: N.G., T.R., J.H.A., A.V., R.M., and E.B. reports no disclosures. K.M.M. reports grants or personal fees from Biogen, Novartis, Roche, Teva and Sanofi, outside the submitted work. E.G.C. reports grants or personal fees from Almirall, Biogen, Merck, Novartis, Roche, Sanofi Genzyme and Teva, outside the submitted work. Ø.T. reports personal fees from Biogen, Merck, Sanofi, Roche, and Teva, outside the submitted work., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objective: We aimed to determine the effectiveness of natalizumab (NTZ) by assessing overall No Evidence of Disease Activity 3 (NEDA-3) in a local Norwegian cohort. Background: NTZ is an immunomodulating drug used in the treatment of multiple sclerosis (MS). It has typically been used as a second-line treatment, but certain patients with high disease activity have started directly with NTZ. Methods: This retrospective cohort study includes all patients who received NTZ for relapsing-remitting MS at Nordland Hospital in the period 2008-2018. In June 2019, status for every patient was assessed, and a survival curve was used to show the cumulative probability of achieving NEDA-3 over time. Results: The cohort consisted of 66 patients, 49 women and 17 men with a mean age of 40.0 ± 10.8 years. Each patient received on average 45.8 ± 36.4 NTZ infusions. Mean age and Expanded Disability Status Scale (EDSS) at first infusion was 34.8 ± 10.5 and 3.2 ± 1.9, respectively. Prior to NTZ treatment, 83% had used other disease modulating drugs and 65% were anti-JC virus (JCV) seronegative. During the study period, seven patients converted to seropositive. In 2019, 40 patients had switched or stopped treatment: 19 due to positive JCV serostatus, 9 due to disease activity, 7 due to adverse effects or complications (1 progressive multifocal leukoencephalopathy), 2 due to pregnancy, and 3 due to autologous hematopoietic cell transplantation abroad. Three patients experienced rebound in the wake of discontinuation (7.5%). Of the patients receiving NTZ for more than 3 years ( n = 33), 50% had achieved NEDA-3 after 3 years. Compared to those with evidence of disease activity (EDA), these NEDA-3 patients had significant lower EDSS score before first NTZ treatment ( p = 0.04). They were also slightly, but not significantly, younger at debut of their MS, at the diagnosis and at first NTZ treatment. Of all the patients who ever started on NTZ, 23% had achieved NEDA-3 5 years later. The mean EDSS in 2019 was 3.6 ± 2.5. Conclusion: Despite the high rate of treatment switch, mainly due to the risk of PML, almost one in four who started on NTZ achieved NEDA-3 after 5 years, and the overall disease progression was low in the total cohort. Treating less advanced disease seems to predict better long-term stability., Competing Interests: EB has received honoraria for giving lectures from Sanofi. KA has received honoraria for giving lectures from Biogen, Allergan, Roche, Teva, and Novartis. He has also served in an advisory board for Biogen Norway, and has enrolled patients in the tysabri observational program (TOP) study. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Jaklin, Benjaminsen and Alstadhaug.)

Background: Whether disease-modifying therapies (DMTs) influence cancer in multiple sclerosis (MS) is uncertain., Objectives: Assess incidence of cancer diagnosis among Norwegian MS patients compared to the general population in 1953 to 1995 and 1996 to 2017-reflecting era before and after introduction of DMTs., Methods: We performed a nationwide cohort study comprising 6949 MS patients and 37,922 controls, matched on age, sex and county. The cohort was linked to Norwegian Cancer Registry, Cause of Death Registry and National Educational database. We used Poisson regression to calculate incidence rate ratio (IRR) of cancer., Results: During 1953-1995 MS patients had similar cancer frequency compared to controls (IRR: 1.11 (95% Confidence Intervals (CI): 0.90-1.37)), although MS patients had increased frequency of cancer in endocrine glands (IRR: 2.51 (1.27-4.93). During 1996-2017 we identified significant increased frequency of cancer among MS patients compared to controls (IRR: 1.38 (95% CI: 1.28-1.52): in brain (IRR: 1.97 (1.41-2.78)), meninges (IRR: 2.44 (1.54-3.77)), respiratory organs (IRR: 1.96 (1.49-2.63)). The excess cancer diagnosis was most frequent among MS patients ≥ 60 years of age (HR 1.30 (1.15-1.47))., Conclusion: Incidence of cancer among MS patients compared to controls was higher in 1996 to 2017, corresponding in time to the introduction of DMT for MS. This was observed more frequently among MS patients older than 60 years of age., (Copyright © 2021. Published by Elsevier B.V.)

Background: Knowledge of comorbid disorders is important to optimize therapy for multiple sclerosis (MS), but data are limited. The aim of this study was to assess comorbidity in persons with MS living in Nordland County on January 1, 2017., Methods: Data were retrieved from the Norwegian Patient Registry (2008-2017) and validated through review of electronic hospital charts (1970-2017). Comorbidity was defined as any distinct disorder, classified in the International Classification of Diseases (ICD-10), that had existed or occurred after the diagnosis of MS was established., Results: Data from 637 subjects were reviewed, and 97.5% were registered with at least one comorbid condition. Malignant melanoma was found in 0.5%, and non-melanoma skin cancers in 1.9%. In female subjects, breast cancer was found in 3.3%. Hypothyroidism was confirmed in 3.1%, type-1 diabetes in 0.3%, type-2 diabetes in 3.9%, psychosis in 0.6%, epilepsy in 2.8%, myocardial infarction in 1.7%, subarachnoid hemorrhage in 0.2%, cerebral infarction in 0.6%, pulmonary embolism in 0.9%, inflammatory bowel disease in 1.3%, and rheumatoid arthritis in 0.6%., Conclusion: Compared to reports from other Norwegian epidemiological studies, a higher proportion of inflammatory bowel disease and epilepsy was found. This is in accordance with findings from other studies. The prevalence of non-melanoma skin cancers was significantly higher than in the general Norwegian population as they were reported by The Cancer Registry of Norway., (Copyright © 2020. Published by Elsevier B.V.)

Background: Risk of cancer in multiple sclerosis (MS) patients compared to their siblings is unknown., Objective: The objective was to prospectively investigate the risk of cancer among MS patients compared to siblings without MS and to population controls., Methods: We retrieved data on MS patients born between 1930 and 1979 from the Norwegian Multiple Sclerosis Registry and population studies and on cancer diagnosis from the Cancer Registry of Norway. We used adjusted Cox proportional hazard regression to estimate cancer risk among 6883 MS patients, 8918 siblings without MS, and 37,919 population controls., Results: During 65 years of follow-up, cancer risk among MS patients was higher than that among population controls (hazard ratio (HR) = 1.14, 95% confidence interval (CI): 1.05-1.23) in respiratory organs (HR = 1.66, 95% CI: 1.26-2.19), urinary organs (HR = 1.51, 95% CI: 1.12-2.04), and the central nervous system (HR = 1.52, 95% CI: 1.11-2. 09). Siblings had higher risk of hematological cancers compared with MS patients (HR = 1.82, 95% CI: 1.21-2.73) and population controls (HR = 1.72, 95% CI: 1.36-2.18)., Conclusion: MS patients were associated with increased risk of cancer compared to population controls. Siblings had increased risk of hematological cancer. This indicates that MS and hematological cancer could share a common etiology.

Background: Health registries may yield important data for epidemiological studies. However, in order to be a valuable source for information, the registered data have to be correct., Objectives: The aim of the study was to validate data from the Norwegian Patient Registry (NPR) regarding multiple sclerosis (MS)., Materials and Methods: We obtained data on individuals residing in Nordland County and registered with a MS diagnosis in the NPR or in local hospital records. The NPR data included a unique 11-digit personal identity number that made it possible to identify the individuals medical records. For each individual registered with MS in the NPR, the hospital record was scrutinized in order to confirm or rule out the diagnosis., Results: In Nordland County, 657 individuals had MS 1 January 2017. Of these, 637 were recorded with a correct diagnosis of MS in the NPR, while 59 were recorded incorrectly. Incorrect registration was due to a diagnosis that did not fulfill the diagnostic criteria, later investigation had ruled out MS or it was an error in the diagnostic code registration process. Twenty individuals were not registered with MS in the NPR. These were patients who received their diagnosis before data in the NPR were person identifiable (before 2008), and who later had no MS-registered contact with public specialist healthcare services. The sensitivity is 0.97, and the positive predictive value is 0.92., Conclusion: Data from the NPR gave a good estimate of the occurrence of MS, but nearly one in 10 registered diagnoses was not correct., (© 2019 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.)

Objective: There are some indications of increasing incidence of amyotrophic lateral sclerosis (ALS). Awareness of cognitive impairment in ALS has increased in recent years. We describe the epidemiology and clinical features of ALS in a county in northern Norway over a period of 15 years., Methods: All patients with motor neuron disease (MND) living in Nordland County in the period 2000-2015 were identified and the medical records were scrutinized. The average annual incidence was calculated for the whole period and for five-year periods. Prevalence point was 1 January 2015., Results: We identified 74 cases with MND. The crude point prevalence was 4.1 per 100,000. The average annual incidence was 2.1 per 100,000 for the whole period, 2.0 in the period 2000-2004, 2.3 in 2005-2009, and 2.0 in 2010-2014. All except one of the 22 patients with other forms of MND developed ALS during the course of the disease. The mean survival time was 38 months, patients with bulbar symptoms at diagnosis had a mean survival time of 29 months and those with solely spinal symptoms had a mean survival time of 50 months. Seven patients were diagnosed with frontotemporal dementia (FTD)., Conclusion: The incidence was stable during the study period. Other forms of MND converts to clinical ALS given time. Survival time is almost two years shorter in patients with bulbar symptoms at the first examination, compared to those with solely symptoms from spinal muscles. FTD was found in 9% of the patients.

Purpose: The prevalence of epilepsy among patients with multiple sclerosis (MS) has been found higher than in the general population. Although cortical pathology may be involved, the causal link between MS and epileptic seizures is still unclear. We aimed to identify and describe the patients with active epilepsy in a previously described population based MS-cohort., Methods: Medical records of all patients with MS in Nordland County on January 1, 2010, were scrutinizing for evidence of comorbid seizures and epilepsy., Results: Among 431 patients with MS, we identified 19 (4.4%) with a history of seizures or epilepsy. Fourteen (3.2%) of these had active epilepsy defined as use of antiepileptic drugs or seizures within the last 5 years. One patient got epilepsy before other signs of MS. In patients with relapsing-remitting MS (RRMS) at onset and active epilepsy (n=10), 70% had converted to secondary progressive (SPMS) at prevalence date, compared to only 35% of those without active epilepsy (p=0.02). 43% had converted to SPMS before they got epilepsy. Attack semiology or electroencephalogram recordings indicated a focal onset of seizures in 12 of 14 (86%) with active epilepsy., Conclusion: The frequency of active epilepsy among MS patients in Nordland was 3.2%, approximately 4.5 times higher than in the general Norwegian population. RRMS patients with active epilepsy had more likely converted to SPMS than patients without active epilepsy. With a high frequency of focal epilepsy, the study supports that focal MS brain pathology is the cause of the comorbid epilepsy., (Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Background: The conflicting results from studies on socioeconomic status (SES) and multiple sclerosis (MS) risk might be due to a change in the distribution of environmental exposures over time or to methodological limitations in previous research., Objective: To examine the association between SES and MS risk during 50 years., Methods: We included patients registered in Norwegian MS registries and prevalence studies born between 1930 and 1979, and identified their siblings and parents using the Norwegian Population Registry. Information on education was retrieved from the National Education Registry, categorized into four levels (primary, secondary, undergraduate and graduate) and compared in patients and siblings using conditional logistic regression., Results: A total of 4494 MS patients and 9193 of their siblings were included in the analyses. Level of education was inversely associated with MS risk ( p trend < 0.001) with an odds ratio (OR) of 0.73 (95% confidence interval (CI): 0.59-0.90) when comparing the highest and lowest levels. The effect estimates did not vary markedly between participants born before or after the median year of birth (1958), but we observed a significant effect modification by parental education ( p = 0.047)., Conclusion: Level of education was inversely associated with MS risk, and the estimates were similar in the earliest and latest birth cohorts., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: EG Celius has received funding for travel, advice and speaker’s fees from Sanofi-Aventis, Merck-Serono, Genzyme, Biogen Idec, Roche, Teva, Almirall and Novartis, and received unrestricted research support from Biogen Idec and Novartis. KM Myhr has participated on scientific advisory boards for Novartis Norway, Biogen Idec, Genzyme and Roche; received funding for travel from Allergan, Bayer, Novartis, Merck-Serono and Biogen; received speaker honoraria from Allergan, Almirall, Bayer, Biogen, Genzyme, Novartis, Merck-Serono and Teva; and received unrestricted research support from Bayer, Genzyme, Novartis, Merck-Serono, Biogen, Pronova Biocare and Bergen and Norwegian MS Society. Ø Torkildsen has served on scientific advisory boards for Biogen Idec, Genzyme and Merck-Serono and received speaker honoraria and travel grants from Genzyme, Merck-Serono, Novartis and Biogen Idec.

Introduction . Takayasu arteritis is a rare disease affecting the aorta and its main branches, causing arterial claudication and end-organ ischemia, including stroke. The etiology is unknown but is believed to be autoimmune. An association between Takayasu arteritis and tuberculosis has been suggested, but the possible relation is unclear. Case Presentation . A 15-year-old Somali boy was diagnosed with latent tuberculosis. He had a lesion in the right lung, and both the tuberculin skin test by the Mantoux method and Quantiferon GOLD test turned out positive. After he suffered a cerebral infarct in the right hemisphere, childhood Takayasu arteritis was diagnosed. The diagnosis was based on diagnostic imaging showing a high-grade stenosis of the origin of the right common carotid artery, an occluded common carotid artery on the left side, a circumferential thickening of the vessel walls in the right and left common carotid artery, and laboratory findings with elevated C-reactive protein. Conclusion . Takayasu arteritis is an uncommon cause of stroke. It should however be kept in mind as a cause of cerebrovascular disease, especially in the young., Competing Interests: The authors declare no competing interests regarding the publication of this paper.

Background: The risk of multiple sclerosis (MS) increases with increasing latitude. Taking into consideration that Norway has a large latitude range, a south-to-north gradient would be expected. However, previous studies have reported an uneven distribution of the disease in Norway, with a relatively low prevalence in the most northern parts of the country. We describe the incidence and prevalence of MS in a county in the north of Norway over a period of 40 years., Methods: All patients with MS living in Nordland County in the period 1970-2010 were identified by reviewing hospital charts. The patients were included if they met the criteria of definitive or probable MS according to Poser [Ann Neurol 13:227-231, 1983] or MS according to McDonalds [Ann Neurol 50:121-127, 2001]. Point prevalence at the beginning of the decades was calculated. The average annual incidence was calculated for 5-year periods., Results: The total crude prevalence on January 1, 2010 was 182.4 per 100 000. The annual incidence continuously increased from 0.7 per 100 000 in 1970 - 1974 to 10.1 per 100,000 in 2005 - 2009. The time delay from the first symptom to diagnosis was stable from 1975 to 2010. The proportion of primary progressive MS in the prevalence numbers was 38.2% in 1980, and decreases continuously, to 18.6% in 2010. The female to male prevalence ratio has been stable since 1990 at 2.2 to 1., Conclusion: The prevalence and the incidence of MS have steadily increased over a 40 year period. Nordland County is a high-risk area for MS.

A month of birth effect on multiple sclerosis (MS) risk has been reported from different countries. Recent critics have suggested that this finding is caused by confounding and that adequately adjusting for year and place of birth would markedly reduce this effect. All inhabitants in Norway are registered in the Norwegian Population Registry (Statistics Norway), making this an ideal area for performing adjusted analyses. Using the entire Norwegian population born between 1930 and 1979 (n = 2,899,260), we calculated the excess between observed and expected number of births for each month for 6649 Norwegian MS patients, 5711 mothers, 5247 fathers, and 8956 unaffected siblings. The analyses were adjusted for year of birth and place of birth according to the 19 counties in Norway. An unadjusted analysis revealed 13% fewer MS births than expected in February (P = 0.0015; Bonferroni corrected P = 0.018), 10% more in April (P = 0.0083; Bonferroni corrected P = 0.0996) and 15% more in December (P = 0.00058; Bonferroni corrected P = 0.007). Adjustments for both year and place of birth significantly altered our results for February and December, but even after these adjustments there were still 10% more MS births than expected in April (P = 0.00796; Bonferroni corrected P = 0.096). MS patients had a higher incidence of April births than their siblings (Fisher-exact test; P = 0.011), mothers (Fisher-exact test; P = 0.004), and fathers (Fisher-exact test; P = 0.011) without MS. Adjustments for confounding significantly affected our results. However, even after adjustments, there appears to be a persistent higher than expected frequency of April births in the MS population.

Objective: We aimed to determine if the risk of Multiple Sclerosis (MS) is associated with month of birth in Norway and to explore a possible latitudinal gradient., Methods: All patients with MS born between 1930 and 1979 registered in the Norwegian MS Registry or ascertained in Norwegian prevalence studies were included (n = 6649). The latitude gradient was divided in Southern, Middle and Northern Norway, according to the estimated regional yearly mean vitamin D effective UV dose., Results: Risk of MS was 11% higher for those born in April (p = 0.045), and 5% higher for those born in May (p = 0.229), 5% lower for those born in November (p = 0.302) and 12% lower for those born in February (p = 0.053) compared with the corresponding population, unaffected mothers and siblings. In Southern Norway the odds ratio of MS births in April and May was 1.05 (0.98-1.24), in Middle Norway 1.11 (0.97-1.27) and in Northern Norway 1.28 (1.0-1.63) compared with the other months., Conclusions: This study confirms previous reports of increased MS births in spring and decreased MS births in the winter months. This could support the role of decreased sunlight exposure during pregnancy and vitamin D deficiency in prenatal life in MS.

A remarkable increase in female to male ratio of multiple sclerosis (MS) is recognised in high incidence areas. Norway is a high-risk area for MS, spanning latitudes 58-71 °N. We studied whether the sex ratio has changed over time and whether it differs by clinical phenotype or by latitude. Population-based epidemiological data and data from the Norwegian MS Registry on patients born from 1930 to 1979 were combined in this study. Place of birth was retrieved from the Norwegian Population Registry and information on clinical subtypes was obtained from the Norwegian MS Registry. The female to male ratio ranged from 1.7 to 2.7 (median 2.0) in 5,469 patients born in Norway, and increased slightly by 5-year blocks of year of birth (p = 0.043). The sex ratio was 2.6:1 in 825 patients born 1970-1979, which is significantly higher than in those born 1930-1969 (p < 0.001). In patients with relapsing remitting onset, the sex ratio was 2.4:1, while it was 1.1:1 in those with primary progressive disease. The sex ratio did not differ between the south, the middle and the north of the country. The overall sex ratio of MS is strongly determined by cases with relapsing remitting onset. We did not observe the remarkable increase in sex ratios of MS reported from other high-risk areas. The high sex ratio in the youngest birth cohorts may change as an increasing proportion of cases in this age group is being diagnosed. Sex ratio was not associated with latitude.

28 year-old woman developed sensory loss in the gluteal region and involuntary micturition during sleep. After two days she arrived at the Department of neurology. Examination disclosed absence of the right ancle reflex (S1), sensory loss in the saddle area including the dermatomes S1-S5, absence of the ano cutan (S3-S5) and bulbocavernous reflexes (S3-S4). She had sphincter disturbance and a sensory palsy of the bladder, but no retention. She experienced no vertebral, radicular or other pain at any time. Because of the lack of pain, the tentative diagnosis was acute myelitis, and a CT scan was not done. A further investigation with MRI vas postponed to the next day. The MRI scan showed a large herniation of the L5/S1 disc, with significant affection of the cauda equina. The patient went to surgery with laminectomia and extirpation of the hernia. This case illustrates that a disk herniation with a cauda equina syndrome is not necessarily painful.

Sixtyfour mares were examined 3 and 6 weeks after mating. Progesterone was measured in 22 mares 3 weeks after mating in order to see if this could be of any help in the oestrous diagnosis. None of the pregnant mares had plasma progesterone below 2 ng/ml. Pregnant mares that did not show oestrus had higher levels of plasma progesterone than pregnant mares showing signs of oestrus 3 weeks after mating. Clinical findings in pregnant and nonpregnant mares 3 weeks after mating is compared, and oestrus in pregnant mares is discussed.

Ovarian function and carbohydrate status were examined in 286 dairy cows. The cows, which were at various stages of the postpartum period, had their ovaries examined by one rectal palpation. Simultaneously with the clinical examination, one blood sample was taken for determination of progesterone, glucose and acetoacetate. In the period before 24 days post partum cows not having a corpus luteum had somewhat lower plasma glucose than cows having a corpus luteum (P less than 0.05). Cows not having a corpus luteum after 40 days showed a tendency to lower plasma glucose and higher plasma acetoacetate than cows having corpus luteum (P less than 0.05). Ovarian activity, expressed through frequency of high progesterone values (greater than or equal to 2 ng/ml), increased markedly after 40 days post partum, while the lowest glucose means and highest frequencies of acetoacetate greater than or equal to 2.5 mg/100 ml occurred before 30 days post partum. It is concluded that longitudinal studies post partum will be required to clarify the possible effect of hypoglycemia on the ovarian function.

Forty-seven heifers with the diagnosis anoestrus were treated with 15 mg to 60 mg megestrolacetat (Niagestin "NOVO") per os for 10 days. Thirty heifers showed oestrus within 10 days after treatment and 56% of these conceived after first insemination. There was no significant difference in fertility after different doses of megestrolacetat. Ten cycling heifers were synchronized with 50 mg megestrolacetat per os for 14 days. On the first day of treatment 5 mg oestradiolvalerat was given intramuscularily. All heifers came into heat and were inseminated 2--4 days after treatment. Fifty per cent were pregnant 55 days after insemination. Dosage of megestrolacetat for cows and heifers are discussed.

The ovarian activity in 33 primiparous and 52 pluriparous post weaning sows was studied by progesterone determination. The progesterone profiles revealed that 90.4 per cent of the pluriparous and 66.7 per cent of the primiparous sows had resumed ovarian activity within 10 days. Ovulation within 10 days with overt oestrus occurred in 45.5 per cent of the primiparous and in 53.8 per cent of the pluriparous sows. Ovulation without detectable heat ('silent heat') occurred in 31 per cent of all sows during the first 10 days after weaning. The ability to resume ovarian activity was better in sows weaned in the period January to June than in sows weaned from July to December. Irregularities of luteal function were seldom observed in unmated sows. In mated sows which later proved to be non-pregnant, high progesterone values were common three weeks after mating.

The accuracy in using different types of ultrasound equipment (puls echo and Doppler) and rectal examination for pregnancy control in the sow was studied. The ultrasound instrument of the puls echo type had low accuracy in non pregnant sow and high frequency of uncertain diagnosis. Concerning the Doppler instrument the accuracy was lowest in pregnant sows. This instrument had low frequency of uncertain diagnosis. Of the two ultrasound instruments studied, the Doppler instrument was considered the most suitable for pregnancy examination in the sow. Rectal examination gave 100% correct diagnosis in the period 30-60 days after mating. Some sows were examined rectally 19-24 days after mating, but during this period the diagnoses were uncertain.