Effect of pre- and post-partum supplementation with lipid-encapsulated conjugated linoleic acid on milk yield and metabolic status in multiparous high-producing dairy cows.

We evaluated the lactation performance, liver lipid content and plasma metabolites indicating the energy balance of dairy cows supplemented with conjugated linoleic acid (CLA) pre- and post-partum (PP) vs. only PP. A total of 60 cows were divided into three groups (n = 20). Daily diet of cows was supplemented with 14 g of CLA (7 g cis-9, trans-11 and 7 g trans-10, cis-12 isomers) from week 3 before the expected date of calving (group CLA1), or from the day of calving (group CLA2) until 77-91 days PP. Control cows were fed an isocaloric, isonitrogenous and isolipidic diet without CLA. Between week 3 and week 6 PP, the milk yield of cows in both CLA-treated groups was approximately 4.5 kg higher (p < 0.05) than in control. Milk fat concentrations decreased from week 3 and were lower in both CLA groups than in control (p < 0.01). Body condition score loss was lower (p < 0.05) in the CLA1 than in the control group on week 5 PP. By week 11 PP, the body condition of both CLA1 and CLA2 groups exceeded that of control. Plasma non-esterified fatty acid was lower in CLA1 compared to CLA2 and control during the early PP period (p < 0.05), while this difference faded away by the late PP period. Beta-hydroxybutyrate (BHBA) increased rapidly in all groups following calving. In CLA1 group, it began to decrease sooner than in CLA2 and control. The prevalence of subclinical ketosis (BHBA > 1.2 mm) was lower in CLA1 group than in CLA2 and control (p < 0.05). Liver biopsy analyses showed that CLA1 treatment decreased (p < 0.05) the total lipid content of liver compared to control at week 5 after calving. Our results show that CLA supplementation is more efficient in alleviating body mass mobilization and decreasing the incidence of subclinical ketosis when applied as early as 3 weeks before calving than started feeding after calving.

Reproductive features and faecal progesterone metabolite profile in female ferrets.

Elevated post-partum progesterone metabolite (P(4) -met) levels have been recently postulated to occur in lactating lynxes. The aims of this study were to monitor reproductive features in female ferrets, changes in the faecal P(4) -met concentrations throughout the breeding season and ovarian activity in post-partum lactating and non-lactating (NL) female ferrets. Our results indicate that coinciding with the results described in the lynx, elevated faecal P4-met concentrations occur in lactating ferrets, furthermore, that the duration of elevated secretion of P(4) seems to be dependent on the duration of lactation (P4-met at delivery, n=47: <500 ng/g; 5-7 days after delivery, during lactation, n=47: ≥ 500-800 ng/g; in females weaned at delivery, n=4: baseline levels). Three days after ovariohysterectomy of lactating females, P(4) -met concentrations decreased to baseline levels. In lactating females, the ovarian stroma is more active than that in NL ones implicating that the ovary is at least in part responsible for the elevated P4-met concentrations. Ovaries of lactating females contained many luteinized cells either as luteinized granulose cells in the wall of late pre-antral/early antral follicles or as corpus luteum (CL)-like structures. Early resumption of the entire ovarian activity (developed follicles and oestrus) occurs in NL post-partum females, while final follicular development is blocked (follicles stalls at antral stage) in the lactating ones (however, occasionally lactational oestrus may occur). We suppose that the elevated faecal P4-met during lactation together with suckling and other hormonal effects may contribute to prevention of early returning to oestrus in nursing female ferrets.

Comparison of four treatments to suppress ovarian activity in ferrets (Mustela putorius furo).

Twenty-five ferret jills were randomly allocated to five groups of five animals; they were treated either before the breeding season with 15 mg medroxyprogesterone acetate (MPA), with 40 mg proligestone or with a slow-releasing device containing 4.7 mg of the gonadotropin-releasing hormone (GnRH) agonist deslorelin acetate (srGnRH), or at spring oestrus with 100 iu human chorionic gonadotropin (hCG), or were left untreated and mated. All the ferrets were assessed for signs of oestrus and their ovarian response was monitored by individual faecal progesterone metabolite (P4-met) profiles. The mean (sd) durations of treatment-induced ovarian quiescence were 94 (18), 99 (40), 53 (9) and 698 (122) days in the group treated with MPA, proligestone, hCG and srGnRH, respectively (P<0.001). Treatment with hCG and srGnRH proved to be the safest, while MPA treatment was associated with most side effects. Both MPA and proligestone treatments caused alopecia in one ferret per group, and after the first return to oestrus and mating an MPA-treated jill had a premature delivery and developed a purulent vaginal discharge. At the first post-treatment mating, the fertility (expressed as the percentage of ferrets mated in the group that produced a litter) was 75 per cent in the MPA-treated group, 60 per cent in the proligestone-treated group, 75 per cent in the hCG-treated group and 0 per cent in the srGnRH-treated group; in the control group, fertility was 100 per cent at mating in spring and 60 per cent at mating in summer. Three srGnRH-treated jills conceived at the second post-treatment oestrus.

Periparturient insulin secretion and whole-body insulin responsiveness in dairy cows showing various forms of ketone pattern with or without puerperal metritis.

To study the effect of time and different forms of hyperketonemia, with or without puerperal metritis, on insulin and glucose responses, 31 Holstein cows were subjected to glucose (GTT) and insulin tolerance tests (ITT) between 18 and 22 d before, and on days 7 and 60-70 after calving. Plasma concentrations of beta-hydroxybutyrate (BHB), nonesterified fatty acids, glucose, insulin, insulin-like growth factor I and leptin were measured from 18 d before until 70 d after calving. The revised quick insulin sensitivity index (RQUICKI) was calculated at each time point. First postpartum (PP) ovulation was monitored by milk progesterone. Based on BHB patterns and clinical findings, animals were classified as 1) Normoketonemic (NK, n=9); 2) Transiently hyperketonemic (tHK, n=7); 3) Continuously HK (cHK, n=7); and 4) Continuously HK, with signs of puerperal metritis (cHK+PM, n=6). Insulin area under the curve (AUC) and insulin response to glucose were significantly lower in the early PP period than in late-pregnancy (P<0.001), and on day 7 after calving in cHK and cHK+PM groups compared to NK and tHK groups (P<0.001). On day 7, insulin stimulated a decrease in plasma glucose in cHK, cHK+PMthan NK, and tHK groups. Normoketonemic cows (group 1) ovulated earlier than all other groups (P=0.002). There was no correlation between GTT and ITT variables and the RQUICKI. Time had a significant effect on RQUICKI. Long-term hyperketonemia, especially combined with puerperal metritis, interacts with secretion of insulin and whole-body IR, and results in a significant delay in PP ovarian activity in dairy cows.

Effect of prepartum energetic supplementation on productive and reproductive characteristics, and metabolic and hormonal profiles in dairy cows under grazing conditions.

The effect of cracked corn grain supplementation (3.5 kg/day) during 3 weeks before the expected calving date on milk production and composition, body condition score (BCS), metabolic and hormonal profiles and length of postpartum anoestrus was evaluated in multiparous Holstein dairy cows under grazing conditions (Energy supplemented group, n = 10; Control group, n = 10). Body condition score was weekly recorded during the peripartum period, from days -21 to +35 (parturition = day 0). Non-esterified fatty acids, beta-hydroxybutyrate, cholesterol, urea, insulin, insulin-like growth factor I (IGF-I), leptin, thyroxine (T(4)) and 3,3''5-triiodothyroinine (T(3)) were weekly determined in plasma from days -21 to +35. The reinitiation of ovarian cyclicity was twice weekly determined by ovarian ultrasonography and confirmed by plasma progesterone concentrations. Cows fed energy concentrate prepartum had higher BCS during the prepartum and postpartum and produced more milk. Non-esterified fatty acids plasma concentrations were significantly higher in the energy group, while cholesterol was higher in the control group. Treated cows had higher levels of plasma insulin, IGF-I and leptin pre-calving. IGF-I, leptin and T(4) were diminished during the early postpartum period in both groups. Insulin levels were also diminished in the control group, but levels remained high in the energy-supplemented group. Treated cows ovulated sooner after parturition than controls. We conclude that Energetic supplementation prepartum in cows under grazing conditions increased milk production and reduced the reinitiation of ovarian activity, consistent with a better EB (BCS), higher prepartum levels of IGF-I, leptin and insulin, and higher insulin levels during early postpartum.

Effects of environmental temperature on thyroid hormones in the barn owl (Tyto alba).

The basic patterns of thyroid hormones [thyroxine (T4) and 3,3',5-triiodothyronine (T3)] and the T4 and T3 responses induced by thyrotropin releasing hormone (TRH) are reported in captive female barn owls (Tyto alba) during the non-breeding period. The main findings of the study, conducted on a total of 10 owls, are as follow: (1) The thyroid gland of barn owl can be stimulated by the classical TRH stimulation test. (2) T3 response was much more pronounced both under cold (around 10 degrees C) and warm (around 20 degrees C) conditions, whereas T4 response ranged so widely that we could not point out any significant change in it. (3) Basal T3 plasma level was significantly (p = 0.036) higher in birds exposed to cold temperature, and they responded to TRH treatment with a lower plasma T3 elevation than the birds kept in a warm chamber. This pattern, however, cannot be explained by increased food intake, but is in agreement with the fact that enhanced T3 level may account for higher avUCP mRNA expression, which results in higher heat production on the cell level. From the results it is concluded that altering T3 plasma level plays a significant role in cold-induced thermoregulation.

Conception rate after fixed time insemination following ovsynch protocol with and without progesterone supplementation in cyclic and non-cyclic Mediterranean Italian buffaloes (Bubalus bubalis).

The aim of this study was to test the effect of progesterone supplementation to Ovsynch protocol in cyclic and non-cyclic Mediterranean Italian buffaloes on conception rate after fixed time artificial insemination. From 169 pluriparous buffaloes, 2 groups were identified and subjected to: (1) Ovsynch protocol (OV; n=83) and (2) Ovsynch protocol with the supplementation of progesterone from days 0 to 7 (OV+PROG.; n=86). All cows were inseminated 16-20 h after the second GnRH administration. Within each group, non-cyclic buffaloes were identified (OV=21 and OV+PROG.=20). Overall conception rate was significantly higher in cyclic compared to non-cyclic buffaloes: 43.7% versus 17.0%, respectively, P=0.001. A significant effect of progesterone supplementation on conception rate was observed in non-cyclic buffaloes (30% versus 4.7%, P=0.04) but not in cyclic buffaloes (51.5% versus 35.7%, P=0.077). Collectively, the presence of a large follicle (>or=10 mm) detected at the beginning of the Ovsynch protocol by ultrasound significantly affected conception rate (44% versus 8%, P=0.01). The findings of the present study suggest that (i) progesterone supplementation to the Ovsynch protocol in buffaloes increases conception rate in non-cyclic animals, (ii) the presence of a large follicle at the beginning of the Ovsynch protocol is a determining factor for a successful synchronization of ovulation and high conception rates and (iii) ultrasound monitoring can improve the overall efficiency by selectively identifying more suitable cycling animals carrying a responsive follicle at the time of first GnRH administration.

Endocrine aspects in pathogenesis of mastitis in postpartum dairy cows.

In well-managed dairy herds some environmental pathogens including Gram-negative (GN) strains (E. coli and others) have been recognized recently as the predominant causative microbes of mastitis in the peri-parturient period. In early weeks of lactation hyperketonaemia may predispose the high-producing cows for GN mastitis. In GN mastitis cytokines, eicosanoids and oxygen radicals are released, which are responsible for the local and systemic symptoms. Experimental administration of endotoxin induces a complex endocrine cascade. Similar changes in plasma levels of cortisol, insulin, insulin-like growth factor-I and thyroid hormones are seen also in severe cases of GN mastitis. However, leptin is not responsible for the anorexia associated with severe mastitis in ruminants. Mastitis can postpone the resumption of ovarian cyclic activity in dairy cows when its outbreak occurs between days 15 and 28 after calving (at the expected time of first ovulation). In cyclic cows severe cases of GN mastitis can induce premature luteolysis or prolong the follicular phase.

Short estrous cycles and estrous signs after premature ovulations induced with cloprostenol and gonadotropin-releasing hormone in cyclic dairy cows.

The aim of the present study was to confirm earlier findings, obtained with a small number of animals, that gonadotropin-releasing hormone (GnRH) can shorten corpus luteum functional life when it is administered 24 h after cloprostenol (PG) treatments given 7-9 days after estrus. In addition, the effects of two treatments, PG alone or PG + GnRH given before mid-diestrus, on signs of estrus were studied. Sixty cows in farm conditions were used in the experiment. Eight days after natural estrus, they were given an intramuscularly (i.m.) treatment of cloprostenol (0.5 mg). The animals were then divided into two groups. One group (n = 25) received an i.m. treatment of gonadorelin (0.1 mg) 24 h after the PG treatment (PG + GnRH group), while another group (n = 35) served as controls without any further treatment (PG group). Estrous signs were recorded. Progesterone concentrations were measured from samples of whole milk. No short cycles were observed in the PG group, whereas 33% of the cows in the PG + GnRH group exhibited premature luteal regression (P < 0.05). Cloprostenol treatment on Day 8 had no effect on the intensity of the estrous signs. Instead, GnRH treatment 24 h after PG treatment weakened the estrous signs significantly (P < 0.01). It is concluded that GnRH administration 24 h after a PG treatment given 8 days after estrus can cause short estrous cycles in some cows on an individual basis.

Bacteriological recovery after intramuscular or intracisternal spiramycin-based drying-off therapy.

Systemic (intramuscular, i.m.) vs. local (intracisternal, IC) routes of spiramycin-based drying-off therapy were compared for efficacy on 65 Staphylococcus aureus infected udder quarters of 38 dairy cows. Single-dose (30,000 IU/kg) i.m. treatment (single i.m. group) resulted in a similarly low bacteriological recovery rate (14%) as seen in the untreated controls (18%). I.m. treatment (30,000 IU/kg) on 4 consecutive days (4 i.m. group) resulted in significantly higher quarter-based recovery rates than that in the single i.m. group. The bacteriological recovery rates obtained in the intracisternal and 4 i.m. groups were quite similar but remained below 50%. Based on these findings as well as on the high cost of the repeated intramuscular treatment regime there is no reason to give extra preference to the systemic application of spiramycin at drying off in the practice.

Effect of low-dose zearalenone exposure on luteal function, follicular activity and uterine oedema in cycling mares.

The effect of 10-day zearalenone administration starting 10 days after ovulation was studied in 6 cycling trotter mares in the summer period. After an entire oestrous cycle (Cycle 1), mares were given 7 mg purified zearalenone per os daily (1 mg/ml in ethyl alcohol) beginning on Day 10 of Cycle 2. Toxin exposure was continued until the subsequent ovulation. Luteal function and follicular activity were monitored daily by rectal palpation, ultrasonography and blood sampling for progesterone. During toxin exposure, all animals were in good physical condition. The toxin had no effect on the length of the interovulatory intervals, luteal and follicular phases. It did not influence significantly the plasma progesterone profiles (logistic curve parameters A1 to A6), the follicular activity (growth rate, maximum size of the ovulatory follicles, maximum number and the time of first increase in the number of large follicles) and the uterine oedema. It is concluded that in cyclic mares the methods used in this study could not detect any adverse effect of zearalenone (administered at a low dose similar to natural exposure) on reproduction.

Review of the microbiological, pathological, and clinical aspects of bovine mastitis caused by the alga Prototheca zopfii.

The mastitis caused by P. zopfii alga is a disease of high-producing, machine-milked dairy cows. It occurs worldwide in tropical and temperate climatic areas, and mostly appears sporadically in a therapy-resistant form. However, in poorly managed dairy herds it may be endemic, causing serious economic losses as a result of decreased milk quality and quantity and culling of infected animals. The biological properties of this pathogenic alga, the laboratory methods available for its isolation and identification, the pathological and clinical features of this form of mastitis, and the principles of its control are reviewed in this paper.

Prototheca zopfii mastitis in dairy herds under continental climatic conditions.

In the last 2 years 223 cases of bovine mastitis caused by Prototheca zopfii infection were identified in 32 large-scale dairy herds. All of these farms were in Hungary, which has a continental type, temperate zone climate. Both the sporadic and epidemic forms of P. zopfii mastitis were observed. All the herds affected by the epidemic form had poor hygienic conditions and suffered from several managerial faults, but no specific predisposing factors could be identified. In almost all of the cases, the type II variant of this pathogen was isolated; however, the type III variant was isolated from three cows. The cows had a higher chance of new infection in the early weeks of lactation and in the summer. The P. zopfii infection usually resulted in a chronic subclinical, or mild clinical, inflammatory process in the udder, and was followed by a dramatic loss in milk production and a permanent increase in somatic cell count. The histopathological findings could be characterized as a progressive interstitial mastitis associated with alveolar atrophy. The self-recovery rate was very low.

Ovarian consequences of low dose peroral Fusarium (T-2) toxin in a ewe and heifer model.

The effect of low dose peroral Fusarium produced T-2 toxin intake upon the ovarian function was evaluated in ewes (n = 30; Trial 1) and heifers (n = 7; Trial 2). Half of the ewes and all of the heifers were fed rich, acidosis-inducing concentrate. The 30 ewes were divided into 6 groups of 5 animals each. They were given 0, 0.3 or 0.9 mg/day (0, 5 or 15 ug/kg) purified T-2 toxin per os for 21 days (3x2 factorial design). Four of the 7 heifers were fed 9 mg/day (25 ug/kg) of the same purified T-2 toxin for 20 days while 3 remained untreated. The estrus cycles in all animals were synchronized prior to the trials and the T-2 exposure was started in the mid-luteal phase. The acidic condition in the rumen was estimated by the determination of urinary net acid-base excretion. The ovarian activity was followed with blood sampling for progesterone on alternate days (Trial 1) or with ultrasonography and sampling for progesterone daily (Trial 2). All of the heifers and concentrate-fed ewes showed a compensated acidosis, during first two thirds of T-2 exposure. In Trial 1, ovarian malfunction manifested as lower P4 peak concentration in the midluteal phase, shortening of the CL lifespan and prolonged follicular phases. These malfunctions were detected in 3 and 3 ewes fed concentrate and 0.3 mg and 0.9 mg T-2 toxin. Lower P4 peak concentration was observed in 1 ewe fed regular diet and 0.9 mg T-2 toxin. None of the control and acidotic groups (0 mg T-2), or ewes fed regular diet with 0.3 mg T-2 showed any ovarian malfunction. In Trial 2, after PGF2, administration the ovulation occured later and the plasma progesterone level remained low (< 3 nmol/l) for a longer period in T-2 treated heifers, than their untreated control mates (5.0+/-0.7 vs 3.7+/-0.5 d, P<0.05 and 8.3+/-0.4 vs 6.3+/-0.9 d, P<0.01, respectively). These results show that the peroral T-2 intake can significantly retard the folliculus maturation and ovulation and perhaps the subsequent luteinisation also in ruminants kept on concentrate-rich diet.

Relationship between thyroid function and seasonal reproductive activity in mares.

The relationship between thyroid function and seasonal reproductive activity in mares was investigated by comparing plasma triiodothyronine and thyroxine concentrations in anoestrous mares and in mares with cyclic ovarian activity during the anovulatory season. In study 1, the diurnal changes in plasma triiodothyronine and thyroxine concentrations on a single day were compared in anoestrous and cyclic mares. The mean thyroxine concentrations were significantly higher (P < 0.001) in the cyclic mares than in the anoestrous mares, whereas mean triiodothyronine concentrations were similar in both groups. In study 2, plasma thyroid hormone concentrations were monitored in mares that foaled before the vernal equinox. Nine mares resumed cyclic ovarian activity shortly after parturition and ten mares remained in anoestrus. Mean plasma triiodothyronine and thyroxine concentrations were significantly lower in the first 60-90 days after foaling in the mares undergoing anoestrus than in the mares undergoing normal ovarian activity after parturition (P < 0.001). In these mares, the increases in triiodothyronine and thyroxine concentrations were associated with the first ovulation after parturition. In study 3, thyroid hormone concentrations were monitored in adult (n=14) and young (n=14) mares. Mean thyroxine concentrations were significantly lower in adult anoestrous mares during the anovulatory period than in cyclic mares and in anoestrous mares before and after the anovulatory period (P < 0.01). Mean plasma triiodothyronine concentrations were also significantly lower (P < 0.001) in anoestrous mares from December until March. There were no significant differences between the plasma triiodothyronine and thyroxine concentrations in young cyclic and anoestrous mares. This relationship between thyroid function and expression of seasonal reproductive activity does not indicate that the thyroid gland is involved in the control of seasonality in horses. The decreased triiodothyronine and thyroxine concentrations in anoestrous mares may be the result of a hypothalamic control similar to that described for seasonal reproductive activity.

Acute phase response in dairy cows with experimentally induced Escherichia coli mastitis.

Six Finnish Ayrshire cows were challenged intramammarily with 1500 CFU of Escherichia coli (E. coli) into single udder quarters, and the challenge was repeated into contralateral quarters 3 weeks later. All cows received flunixine meglumine once, and 3 of them were also treated with enrofloxacin. At the 2nd challenge, treatments were changed vice versa. The development of mastitis was followed by monitoring of systemic and local clinical signs, and with serial milk and serum samples. Intramammary challenge with E. coli produced clinical mastitis in all cows, the severity of the disease varying greatly between the animals. No significant changes between the 2 treatment regimens or sequent challenges were found for any of the clinical parameters. The response of each cow followed the same pattern after both challenges; three of the cows became mildly and the other 3 either moderately or severely affected. Two severely affected cows had to be euthanized because of severe mastitis. Serum haptoglobin and amyloid-A concentrations peaked 2-3 days after bacterial challenge. Serum haptoglobin did not correlate with the severity of the disease. Serum amyloid-A rose gradually in the severely affected cows, and significant differences were found between severely versus moderately or mildly affected cows at day 4. Serum tumor necrosis factor alpha concentrations increased only in the severely affected cows. Serum cortisol response was prolonged in the severely diseased animals, and was significantly lower after the second challenge. Serum nitrite/nitrate concentration increased in the severely affected cows. This indicated excess nitric oxide production during acute E. coli mastitis. Strongly decreased milk production, and high bacterial growth in the infected quarters were best predictors for the outcome from acute E. coli mastitis.

Acute-phase response in dairy cows with acute postpartum metritis.

The diagnostic value of 2 plasma acute-phase proteins, haptoglobin and alpha1-acid glycoprotein, and plasma N-acetyl-beta-D-glucosaminidase enzyme activity were studied in 29 newly calved dairy cows. Nineteen had developed acute metritis with putrid vaginal discharge within 2 wk after calving; 10 were clinically healthy controls. Plasma haptoglobin concentration remained low in most cows with acute postpartum metritis. Only the 3 most severely affected cows exhibited a strong haptoglobin response. These were later culled due to poor condition and reduced fertility. This suggests that in acute uterine infection a highly increased haptoglobin concentration indicates poor prognosis for repeat conception. Plasma alpha1-acid glycoprotein concentration increased in acute postpartum metritis, the response pattern being less prominent than that for haptoglobin. The alpha1-acid glycoprotein concentrations did not correlate with severity of disease, and, consequently, the capacity of alpha1-acid glycoprotein in differentiating genital infections was relatively poor. The highest alpha1-acid glycoprotein concentrations were detected in cows with retained placenta and/or dystocia. Plasma N-acetyl-beta-D-glucosaminidase activity levels did not differ between the cows with acute postpartum metritis and healthy control cows.

Endocrine and reproductive consequences of certain endotoxin-mediated diseases in farm mammals: a review.

After giving an overview of the general pathology of endotoxin-mediated diseases, the authors summarise the endotoxin-induced endocrine changes and their clinical consequences, with particular regard to reproduction. The consequences of temporary activation of the cyclooxygenase-2 and lipoxygenase enzyme systems resulting in elevated release of various prostanoids are discussed in cyclic and pregnant ruminants, sows and mares. The clinical failures attributable to increased glucocorticoid secretion as well as the endotoxin-induced changes in thyroid function and in peripheral level of some other hormones (prolactin, growth hormone and insulin-like growth factor 1) are also reviewed.

Thyroid volumetric measurement and quantitative thyroid scintigraphy in dogs.

Thyroid volumetric measurement combined with quantitative 99mTc-per-technetate thyroid scintigraphy was performed in 62 clinical canine patients having suspected thyroid abnormalities. Euthyroid dogs (n = 22) had a total thyroid size of 3.60 +/- 1.36 cm3, the thyroid/salivary gland region of interest (ROI) ratio was 2.01 +/- 0.55, the thyroid/background ROI ratio was 3.86 +/- 0.90, and 20-min thyroid radioactivity uptake was 1.17 +/- 0.71% of the injected dose (I. D.). By Student's unpaired test, thyroid size of the hypothyroid group (n = 36) was not statistically different from that of the euthyroid dogs, but all other quantitative data (e.g., thyroid/salivary gland ROI ratio = 1.08 +/- 0.56, thyroid/background ROI ratio = 2.32 +/- 0.70, and 20-min thyroid radioactivity uptake = 0.34 +/- 0.22% of the I. D.) were significantly (p < 0.001) lower in hypothyroid than in euthyroid dogs. Evaluating the above-listed quantitative data of separated thyroid lobes by Student's paired test, there was no significant difference between the left and the right lobe either in the euthyroid or in the hypothyroid group.

Diagnosis of hyperadrenocorticism in dogs as compared to human diagnostic methods: a review.

Spontaneous hyperadrenocorticism is a common and well-recognised endocrine disorder occurring in dogs. The biochemical diagnosis of hyperadrenocorticism rests on the documentation of excessive glucocorticoid levels or metabolites in urine or blood. The diagnosis of canine hyperadrenocorticism is historically developed from human methods and based on non-dynamic and dynamic tests and visualisation. In some cases the different ranges of endocrine parameters or metabolites necessitate the modification of human protocols. Elevation of the activity of alkaline phosphatase (AP) and its heat-resistant isoenzyme (SIAP) induced by endogenous or exogenous glucocorticoid excess raise the suspicion of hyperadrenocorticism. Cortisol values in morning urine are related to creatinine concentrations to correct for differences in urine concentration. Theoretically, the administration of dexamethasone (DX) at a relatively low dose (0.01 mg/kg of body weight) can inhibit the pituitary secretion of ACTH and, in turn, decrease endogenous cortisol secretion for as long as 24 to 48 h. Therefore, DX administration to dogs with a functioning adrenocortical tumour would not affect the plasma cortisol concentration at any time following its administration. The high-dose dexamethasone suppression test (HDDS) is based on the observation that the function of adrenocortical tumours is independent of pituitary ACTH and they completely suppress ACTH secretion; therefore, regardless of its dose, dexamethasone is never able to suppress cortisol secretion. HDDS can be combined with the measurement of urinary cortisol/creatinine (c/c) ratio from morning urine samples on three consecutive days. In case of non-suppressible urinary c/c ratio one has to speculate on differentiating adrenal tumour (AT) from non-suppressible pituitary-dependent hyperadrenocorticism (PDH) due to a pituitary tumour arising from the intermediate lobe. Radiocholesterol scintigraphy is a less frequently used technique in the diagnosis of canine Cushing's syndrome (CCS); however, it has the same advantages in the localisation and characterisation of adrenocortical diseases as in humans.