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1.
Thyroid scanning was performed in 135 hyperthyroid cats and 13 normal cats with technetium-99m as pertechnetate (99mTcO4) or with radioactive iodine (131I). Of the hyperthyroid cats, enlargement and increased radionuclide accumulation were found in one thyroid lobe in 38 (27%) and in both lobes in 97 (73%). In two hyperthyroid cats with thyroid carcinoma, extension of tumor into the thoracic cavity was detected. In normal and hyperthyroid cats the radionuclide images produced with 99mTcO4 and 131I were similar; however, the quality of the 99mTcO4 scans was usually better than that of the 131I scans.  相似文献   

2.
Since insufficient iodine intake is widespread among the German population, farm animals should if possible receive iodine above requirement, thus concentrating the trace element in milk, eggs and possibly meat. Experiments with a total of 29 fattening pigs with grain soy-bean meal diets without iodine supplementation or with increasing supplements up to 1000 micrograms iodine/kg diet did not show any effect on growth intensity (gain) and feed efficiency. At and above 125 micrograms supplementary iodine/kg diet the thyroid was not or only little hypertrophied and iodine incorporation into thyroglobulin sufficed to sustain serum T4 concentration. The glucosinolates of rape feeds increase iodine requirement. In an experiment with a total of 36 fattening pigs the thyroid iodine depot was decreased due to rapeseed meal feeding, this in agreement with antithyroid drugs which had been also tested. A thyroid with emptied iodine depot is hardly able to synthesize and release hormone, the serum thyroxine concentration showed a drastic decrease. More iodine may compensate for effects of glucosinolates, however, only with not too much of these compounds in the feed. Excessive iodine dosages (10 mg/kg diet) were compared with supplements in the range of recommendations (100 and 1000 micrograms/kg diet) with a total of 120 pigs in three groups of 40 animals each. The dosage of 10 mg iodine/kg diet decreased serum T3 concentration. The enlarged thyroid with double weight had a very high iodine concentration. In comparison with physiological application (100 or 1000 micrograms iodine/kg diet) the thyroid deposited only little iodine in the group with the excessive iodine intake related to consumed iodine quantity. In case of sufficient and excessive iodine supply--industry of compounds feed applies up to 2.5 mg supplementary iodine/kg diet--T4 and iodine of serum but also thyroid weight cannot serve as markers. This range of usual iodine supply is better characterized by the iodine depot of the thyroid. As a rule, thyroid weight increase indicates glucosinolate effects, generally those of dietary antithyroid compounds, more seldom it shows extreme and longterm iodine undersupply or iodine excess.  相似文献   

3.
This study assessed the effects of dietary selenium (Se), iodine (I) and a combination of both on growth performance, thyroid gland activity, carcass characteristics and the concentration of iodine and selenium in Longissimus lumborum (LL) muscle in goats. Twenty‐four bucks were randomly assigned to four dietary treatments: control (CON), basal diet without supplementation, basal diet + 0.6 mg Se/kg dry matter (DM) (SS), 0.6 mg I/kg DM (IP), or combination of 0.6 mg/kg DM Se and 0.6 mg/kg DM I (SSIP) and fed for 100 days. Animals fed diet SSIP exhibited higher (P < 0.05) body weight and better feed conversion ratio (FCR) than those fed other diets. Dressing percentage of goats fed the supplemented diets was higher (P < 0.05) than that of the control. Carcasses from the IP group had higher (P < 0.05) total fat proportion than the SSIP group. The levels of both elements were significantly elevated (P < 0.05) in LL muscle in supplemented goats. Thyroid follicular epithelial cells of IP and SSIP animals were significantly higher than those of CON and SS groups. The study demonstrated that the combined Se and I dietary supplementation improves growth performance, carcass dressing percentage and increases the retention of Se and I in goat meat.  相似文献   

4.
Administration of iodinated contrast medium interferes with iodide uptake in the human thyroid gland and compromises diagnostic thyroid scintigraphy and radioiodine treatment for 4–6 weeks. However, the degree and duration of inhibition of thyroid uptake of pertechnetate (99mTcO4?) by iodinated contrast medium has not been established in any species. The main objective of this study was to better understand the temporal characteristics and magnitude of inhibition of feline thyroid uptake of 99mTcO4? due to iohexol administration. Routine thyroid scintigraphy was performed in eight cats by intravenous (IV) injection of 185 MBq (5 mCi) of 99mTcO4? both 4 days before and 0,1, 3, 7,14, and 28 days after IV administration of 880 mg I/kg iohexol (240 mg I/ml). Thyroid scintigraphy data were used to calculate thyroid:salivary gland ratios (T:S) and the percentage of total injected 99mTcO4? dose uptake within the thyroid (%TU) at 20 min postinjection. After iohexol administration, mean T:S was significantly decreased below baseline only on day 1. At no point during the study did any cat have a T:S that fell below the published normal reference range of 0.71±0.14. There was a significant decrease in %TU on day 1, 3, and 14; however, at no point during the study, did any cat have a %TU that fell below the published normal reference ranges of 0.64±0.57, 0.68±0.9, or 0.75±1.38.  相似文献   

5.
The purpose of this study was to determine the selenium (Se) requirement in kittens. Thirty-six specific-pathogen-free kittens (9.8 weeks old) were utilized in a randomized complete block design to determine the Se requirement in cats with gender and weight used as blocking criteria. Kittens were fed a low Se (0.02 mg/kg Se) torula yeast-based diet for 5 weeks (pre-test) after which an amino acid-based diet (0.027 mg Se/kg diet) was fed for 8 weeks (experimental period). Six levels of Se (0, 0.05, 0.075, 0.10, 0.20 and 0.30 mg Se/kg diet) as Na2SeO3 were added to the diet and were used to construct a response curve. Response variables included Se concentrations and Se-dependent glutathione peroxidase activities (GSHpx) in plasma and red blood cells (RBC) as well as plasma total T3 (TT3) and total T4 (TT4). No significant changes in food intake, weight gain or clinical signs of Se deficiency were noted. Estimates of the kitten's Se requirement (i.e. breakpoints) were determined for RBC and plasma GSHpx (0.12 and 0.15 mg Se/kg diet, respectively), but no definitive breakpoint was determined for plasma Se. Plasma TT3 increased linearly, whereas plasma TT4 and the ratio of TT4 : TT3 decreased in a quadratic fashion to dietary Se concentration. The requirement estimate determined in this study (0.15 mg Se/kg) for kittens is in close agreement with other species. As pet foods for cats contain a high proportion of animal protein with a Se bioavailability of 30%, it is recommended that commercial diets for cats contain 0.5 mg Se/kg DM.  相似文献   

6.
A technique for performing thyroid scintigraphy in the cat using technetium 99m pertechnetate is presented. Two groups of cats were studied: group I—five young adult cats, and group II—five cats, nine to 11 years of age. The resultant scintigrams were uniform in appearance with no significant differences between groups I and II. Computer analysis was performed to determine radioactivity ratios, comparing thyroid with salivary gland and background radioactivity. A consistent thyroid/salivary ratio (T/S) of approximately 1 was obtained for group I and group II. Thyroid/background ratio (T/B) was variable.  相似文献   

7.

Background

The effect of feeding a limited iodine diet on radioactive iodine uptake in the thyroid glands of hyperthyroid cats is unknown.

Objectives

To determine how feeding limited dietary iodine affects radioactive iodine uptake by the thyroid glands of hyperthyroid cats.

Animals

Eight geriatric cats with spontaneous hyperthyroidism.

Methods

Prospective study of eight client owned hyperthyroid cats fed a commercially available iodine limited diet for 6 months. Clinical signs were evaluated and TT4 and fT4 were measured during consumption of the diet. Uptake of 123I was determined before and 8–16 weeks after exclusive consumption of the diet.

Results

Clinical signs of hyperthyroidism resolved in all cats, but there was no significant increase in body weight. TT4 and fT4 decreased into the reference range by 8–16 weeks in all cats. Mean TT4 before consumption of the diet was 9.7 μg/dL (SD 5.2) and after consumption of the diet was 3.1 μg/dL (SD 0.9). Scintigraphy revealed unilateral uptake of isotope in 5 cats and bilateral uptake in 3 cats. Mean percentage uptake of 123I by the thyroid gland at 8 hours after isotope administration was 16.2 (SD 11.8) before diet consumption and 34.6 (SD 11.7) 8–16 weeks after exclusive consumption of the diet. The percentage increase was variable between cats (38–639%).

Conclusions and clinical importance

Limited iodine diets increase iodine uptake in the autonomous thyroid glands of hyperthyroid cats. Further studies are necessary to determine if consumption of a limited iodine diet changes sensitivity of the thyroid gland to 131I treatment.  相似文献   

8.
The aim of the present study was to assess the influence of different levels of iodine supplementation on animal growth and the iodine content of food from beef cattle. In a dose–response experiment with 34 growing fattening bulls of the “German Holstein” breed, in the range from 223 to 550 kg body weight, three iodine dosages were tested. The animals were fed a corn silage/concentrate ration. Iodine concentration in the diet amounted to 0.79 (Group 1), 3.52 (Group 2) and 8.31(Group 3) mg I per kg dry matter (DM). After slaughtering, I was determined in blood, serum, plasma, thyroid, liver, kidneys and meat (M. longissimus dorsi, M. glutaeus medius) by ICP-MS. I-supplementation did not significantly influence DM intake, daily weight gain (1453 (1), 1419 (2) and 1343 (3) g; p > 0.05) or slaughtering performance, but the weight of the thyroid gland increased significantly with the highest I dosage (32 (1), 26 (2) and 42 (3) g animal− 1, p < 0.05). I-supplementation significantly increased I-concentration in muscle, liver, kidney and thyroid gland (p < 0.05). The contribution of beef food to I-intake of humans is relatively low, therefore there is no need to reduce the EU-upper limit (10 mg kg− 1 feed) for growing fattening cattle from the view of consumer safety. In view of animal health and performance more dose–response studies seem to be necessary.  相似文献   

9.
Twenty-eight varieties of commercially-available cat food (23 canned, 5 dried) were analysed for iodine. The iodine concentration varied from less than 0.37 micromol/kg to 41.8 pmol/kg, wet weight (less than 1.48 micromol/kg to 167 micromol/kg, dry weight). Excessive or insufficient iodine intake or wide swings in iodine intake over prolonged periods may contribute to thyroid disorders in cats.  相似文献   

10.
Urine protein/creatinine (UP/C) ratios and 24-hour urinary protein excretion were compared in clinically normal cats and cats with surgically induced chronic renal failure (CRF). Mean 24-hour urinary protein excretion in 30 clinically normal cats fed a 28% protein diet (dry weight basis) was 4.93 mg/kg/24-hour (SD = 1.34) with a range of 2.99 to 8.88. Mean UP/C ratio in these cats was 0.134 (SD = 0.037) with a range of 0.073 to 0.239. Mean 24-hour urinary protein excretion in CRF cats was 10.49 mg/kg/24-hour (SD = 11.28) with a range of 2.16 to 62.93. Mean UP/C ratio in the CRF cats was 0.359 (SD = 0.374) with a range of 0.061 to 1.916. Linear regression showed high correlation (R2 = 0.973, P less than 0.001) between 24-hour urinary protein excretion and UP/C ratio in clinically normal cats and cats with surgically induced chronic renal failure. The regression equation for 24-hour urinary protein excretion versus UP/C ratio was: 24-hour urinary protein excretion = 29.39 (UP/C) + 0.18. Results of this study indicate that UP/C ratios are a valid estimate of 24-hour urinary protein excretion in clinically normal and CRF cats. Dietary protein intake significantly affected UP/C ratios in clinically normal cats and cats with surgically induced CRF. Therefore, the influence of dietary protein should be considered when interpreting UP/C ratios.  相似文献   

11.
Rapeseed press cake (per kg DM 181 g EE, 341 g CP and 23.3 mmol glucosinolates) was tested in a long-term experiment with a total of sixty pigs (live weight range 24 to 104 kg). The 3 x 2 factorial design consisted of three rapeseed press cake levels (no rapeseed press cake--control, 75 g or 150 g rapeseed press cake per kg diet) each with two iodine dosages (125 or 250 micrograms supplementary iodine per kg diet). Reduced feed intake and depressed weight gain were found in groups receiving 150 g rapeseed press cake per kg diet, which correspond to 3.2 mmol glucosinolates per kg diet. At an inclusion level of 75 g rapeseed-press cake per kg diet no differences in feed intake and growth intensity were recorded in comparison to the rape feed free control. The rapeseed-press cake diet increased the weight of thyroid gland and liver and decreased the serum thyroxine (T4) concentration. Higher iodine dosage increased the serum T4 concentration of pigs receiving 75 g rapeseed press cake per kg diet (= 1.6 mmol glucosinolates per kg diet) to the level of the control group and retarded the enlargement of the thyroid gland. Intake of rapeseed products lowered the iodine content of the thyroid gland, however, there was no significant difference between groups given 1.6 and 3.2 mmol glucosinolates per kg diet. The vitamin A content of the whole liver and the vitamin A serum concentration were not influenced by the diets tested. However, rapeseed press cake and the glucosinolates, respectively, decreased the vitamin A concentration per gram liver due to the organ enlargement and the resulting dilution effect.  相似文献   

12.
Thyroid scintigraphy is currently the reference standard for diagnosing and staging cats with hyperthyroidism, but few studies describing the scintigraphic characteristics in a large number of cats have been reported. The objective of this study was to better characterize thyroid scintigraphy findings by evaluating 2096 consecutive cats with hyperthyroidism that were referred over a 3.5‐year period. Of these cats, 2068 (98.7%) had a high thyroid‐to‐salivary ratio (>1.5), whereas 2014 (96.1%) were found to have a high thyroid‐to‐background ratio (>6.1). When the patterns of the cats’ thyroid disease were recorded, 665 (31.7%) had unilateral disease, 1060 (50.6%) had bilateral‐asymmetric disease (two thyroid lobes unequal in size), 257 (12.3%) had bilateral‐symmetric disease (both lobes similar in size), and 81 (3.9%) had multifocal disease (≥3 areas of increased radionuclide uptake). The number of areas of 99mTcO?4 uptake in the 2096 cats ranged from 1 to 6 (median, 2), located in the cervical area in 2057 (98.1%), thoracic inlet in 282 (13.5%), and in the thoracic cavity in 115 (5.5%). Ectopic thyroid tissue (e.g. lingual or mediastinal) was diagnosed in 81 (3.9%) cats, whereas thyroid carcinoma was suspected in 35 (1.7%) of the cats. The results of this study support conclusions that most hyperthyroid cats have unilateral or bilateral thyroid nodules, but that multifocal disease will develop in a few cats that have ectopic thyroid disease or thyroid carcinoma. Both ectopic thyroid disease and thyroid carcinoma are relatively uncommon in hyperthyroid cats, with a respective prevalence of ～4% and ～2% in this study.  相似文献   

13.
Many hyperthyroid cats referred for thyroid imaging and 131I therapy are concurrently or recently receiving antithyroid medications. The effect of the antithyroid drug, methimazole, on thyroid uptake of 99mTcO4 and 123I was evaluated in 8 normal cats. Quantitative analysis was used to determine the normal percent dose uptake of 99mTcO4 and 123I, the change in thyroid:salivary ratios (T:S) of 99-TcO4 over time, and the duration of the methimazole effect on thyroid uptake of 123I. Methimazole was administered to 5 cats for 3 weeks in which a hypothyroid state was obtained; 3 cats served as non-treatment controls. 99mTcO4 and 8 and 24 hour 123I imaging was repeated after 3 weeks of methimazole therapy (time of maximum T4 suppression). Methimazole was then discontinued and 123I images and serum T4 concentrations were repeated at 1, 4, 9, 15, and 24 days post withdrawal. The percent dose uptake of 99mTcO4 increased throughout the acquisition period with maximum uptake occurring 4 hour post injection. The baseline 20 min. T:S ratio for controls and treatment cats were 0.79 +/- 0.08 and 0.81 +/- 0.05 respectively; with a peak value of 1.29 +/- 0.23 and 1.31 +/- 0.18 at 4 hours. The baseline T:S ratios were not significantly different from 20 minutes to 2 hours, however they were significantly elevated at 4 hours post injection. Baseline, 8 and 24 hour percent dose uptake of 123I were 2.1 +/- 0.42% and 7.04 +/- 1.24%, respectively. There was a significant increase in the T:S ratio in the treatment group at all time points. The 8 hour percent dose uptake of 123I at 1, 4, and 9 days post methimazole withdrawal were significantly increased and peaked at 4 days. The 24 hour uptake was significantly increased at 4 and 9 days, with peak uptake at 9 days post-methimazole withdrawal. The 123I percent dose uptake decreased to baseline values by day 15 post withdrawal. Radioiodine uptake is not inhibited by methimazole treatment in normal cats, and is significantly enhanced after recent withdrawal. This finding is supportive of a "short term rebund effect" with maximal enhanced uptake between 4 and 9 days after discontinuing antithyroid drugs. The increased uptake of 99mTcO4 may also affect the interpretation of 99mTcO4 thyroid scintigraphy for 2-3 weeks.  相似文献   

14.
The effect of a low-selenium diet on thyroid hormone metabolism was investigated in growing kittens. Twelve specific-pathogen-free kittens with ages ranging from 16 to 18 weeks were divided into two groups of equal number with equal sex distribution in each group. One group was fed a yeast-based low-selenium diet (0.02 mg Se/kg diet) while the other group was fed the same diet supplemented with Na2SeO3 at 0.4 mg Se/kg diet for 8 weeks. Food intake, body weight and body weight gain were not affected by the low-Se diet during the study period. However, kittens given the low-Se diet had significantly reduced plasma selenium concentration and glutathione peroxidase activity. Plasma total thyroxine (T4) increased and total 3,5,3'triiodothyronine (T3) decreased significantly in kittens fed the low-Se diet at the end of the study. These results suggest that type I deiodinase in cats is a selenoprotein- or a selenium-dependent enzyme.  相似文献   

15.
Feline hyperthyroidism is a common endocrine disorder. A single dose of 148 MBq (4 mCi) 131I is 95–98% effective for the treatment of hyperthyroidism in cats; however, the cause for treatment failures has not been determined. In a series of 113 hyperthyroid cats having pertechnetate thyroid scintigraphy before treatment using a standard 148 MBq (4 mCi) 131I dose, the thyroid to salivary gland (T:S) ratio and the thyroid to background (T:B) ratio were calculated. Results in 107 (95%) cats successfully treated were compared with results in six (5%) cats that remained hyperthyroid after treatment. T:B ratio was significantly higher for cats that had treatment failure (median 13.0, range 3.6–73.0) than for cats successfully treated (median 4.4, range 1.2–69.0) (P=0.02), whereas there was no significant difference in their T:S ratios (P=0.2). The T:B ratio is a new approach to evaluating the thyroid pertechnetate scan with the intent of identifying which hyperthyroid cats may fail treatment using a standard 148 MBq (4 mCi) 131I dose and which, therefore, require a higher dose.  相似文献   

16.
OBJECTIVES: To determine the effect of sedation and anesthesia on thyroid and salivary gland uptake of technetium Tc 99m pertechnetate ((99m)TcO(4)) in euthyroid cats. ANIMALS: 6 euthyroid cats. PROCEDURES: Thyroid scintigraphy was performed by use of a high-resolution low-energy parallel-hole collimator after IV injection of 117 to 133 MBq (3.16 to 3.59 mCi) of (99m)TcO(4)(-). The procedure was performed 4 times on each cat during different sedative and anesthetic protocols in a rotating schedule as follows: propofol, ketamine-midazolam-atropine, ketaminemidazolam, and medetomidine. Regions of interest were drawn around thyroid and salivary glands and counts corrected for background and decay. Percentage of (99m)TcO(4)(-) uptake in salivary and thyroid glands and thyroid-to-salivary gland (99m)TcO(4)(-) uptake ratio were calculated at 20 and 40 minutes. Relative effects of anesthesia and sedation on salivary and thyroid gland (99m)TcO(4)(-) uptake were compared. RESULTS: Significant differences among sedativeanesthetic protocols were found for thyroid gland (99m)TcO(4)(-) uptake, salivary gland (99m)TcO(4)(-) uptake, and thyroid-to-salivary gland (99m)TcO(4)(-) uptake ratio. Thyroid gland (99m)TcO(4)(-) uptake for the ketamine-midazolam protocol at 20 and 40 minutes after (99m)TcO(4)(-) administration was significantly higher than for the propofol protocol. A significant difference in salivary gland(99m) TcO(4)(-) uptake was found between ketamine-midazolam and ketamine-midazolam-atropine protocols at 40 minutes. The thyroid-to-salivary gland (99m)TcO(4)(-) uptake ratio for the ketamine-midazolam protocol was significantly higher at 40 minutes than for propofol or ketamine-midazolam-atropine protocols. CONCLUSIONS AND CLINICAL RELEVANCE: Sedation and anesthesia have a significant effect on thyroid and salivary gland (99m)TcO(4) uptake in euthyroid cats that may interfere with thyroid scintigraphic image interpretation.  相似文献   

17.
Abnormally low(131)I uptakes were noticed in dogs fed with commercial diets at the University Animal Clinic in Buenos Aires, but the total iodine content of eight different commercial diets examined was found to provide an iodine intake above daily requirements. To investigate this anomaly, 18 dogs were distributed into three groups, fed either: (1) a home-prepared diet; (2) a commercial diet; (3) a home-prepared diet supplemented with potassium iodide equivalent to that found in the commercial diet. The(131)I uptake in dogs of groups B and C was significantly decreased, as was basal serum thyroxine (T(4)) and free thyroxine (FT(4)), whereas urinary iodide excretion and serum thyroid stimulating hormone (TSH), were increased. The thyroid releasing hormone (TRH)-TSH test showed an increased response in dogs from group B, while the TRH-T(4)test was inhibited in both groups B and C. The results demonstrate that the excessive amount of iodine present in some commercial diets in Argentina causes a significant impairment of thyroid function and hypothyroidism.  相似文献   

18.
In the experiment, 2 x 12 growing pigs received 19 or 6.7 mmol glucosinolates + aglucones/kg feed via conventional rapeseed meal (RSM) or RSM of a newly bred variety. These pigs and 24 littermates pair fed with a soya bean meal (SBM) diet were subdivided in groups of 4 animals each. Their diet contained either no supplementary iodine or an iodine supplementation of up to 1 mg/kg feed. In the RSM and SBM groups the lack of additional iodine lowered the serum T4 and T3 content below the detection limit and caused goitre with about 1 mg iodine in the total thyroid. The SBM diet with 0.0625 mg supplementary iodine/kg increased the serum T4 level and reversed the thyroid enlargement but not that of epithelial cells. The hypothyroidism (goitre and serum T4 level approximately 10 nmol/l) still existed in the case of this iodine dosage together with the RSM of the newly bred variety. A serum T4 level comparable to that of the animals fed SBM was only reached by supplementing the low glucosinolate diet with 0.25 mg iodine/kg feed. The iodine content of the thyroid, however, was reduced by 50 per cent. Though thyroid and epithelial cells were enlarged, this enlargement was not so obvious as in animals exposed to higher glucosinolate level. In spite of 1 mg supplementary iodine/kg feed, the feeding of the conventional RSM resulted in a lower serum T4 level a reduced thyroid iodine content and the enlargement of thyroid and that of epithelial cells. Compared to the high glucosinolate RSM, a significantly lower antithyroid effect of the low glucosinolate RSM was found in pigs with iodine supply. The degree of thyroid enlargement and the serum T4 level were the criteria.  相似文献   

19.
Thyroid scintigraphy is commonly used for evaluation of cats with hyperthyroidism, with the thyroid‐to‐salivary ratio (T/S) being the most common method to quantify the degree of thyroid activity and disease. Calculation of thyroid‐to‐background ratios (T/B) or percent thyroidal uptake of 99mTcO?4 (TcTU) has only been reported in a few studies. The purpose of this prospective, cross‐sectional study was to evaluate a number of quantitative scintigraphic indices as diagnostic tests for hyperthyroidism, including the T/S, three different T/B, TcTU, and estimated thyroid volume. Of 524 cats referred to our clinic for evaluation of suspected hyperthyroidism, the diagnosis was confirmed (n = 504) or excluded (n = 20) based on results of a serum thyroid panel consisting of thyroxine (T4), triiodothyronine (T3), free T4 (fT4), and thyroid‐stimulating hormone (TSH) concentrations. In the hyperthyroid cats, median values for TcTU, T/S, and three T/B ratios were all significantly higher (P < 0.001) than values in euthyroid suspect cats or clinically normal cats. All scintigraphic parameters were relatively sensitive and specific as diagnostic tests for hyperthyroidism, but the T/S ratio had the highest test accuracy. The T/S ratio correlated strongly with the TcTU (r = 0.85). However, the TcTU had a higher and more significant correlation (P < 0.01) with serum T4 (r = 0.76 vs. 0.64), T3 (r = 0.77 vs. 0.64), and estimated thyroid volume (r = 0.62 vs. 0.38). Overall, calculation of TcTU is an accurate diagnostic test, but also appears to be the best parameter to predict the functional volume and metabolic activity of the feline adenomatous thyroid gland.  相似文献   

20.
In a study using a total of 36 German Simmental beef bulls weighing between 236 kg and about 620 kg the question of what constitutes an adequate Co supply was investigated with reference to the performance criteria growth, feed intake, energy intake, nutrient intake and carcass criteria. The bulls received a diet of corn silage ad libitum and 2.5 kg concentrate for a period of 280 days. Ten rations (R) with graduated Co supplements were fed with mean concentrations of 0.07 (R1), 0.09 (R2), 0.11 (R3), 0.15 (R4), 0.18 (R5), 0.26 (R6), 0.33 (R7), 0.42 (R8), 0.59 (R9) and 0.69 (R10) mg Co per kg dry matter (DM) intake. The Co supplement was added as CoSO47H2O. The diets with no or low Co supplementation produced either distinctly lower daily gains of 1045g (R1) and 1130g (R2) or lower daily gains of about 1260 g (R3, R4) than rations R5–R10, where daily gains averaged 1340 g. The mean daily feed intake per animal was also significantly or marginally affected with values of 6.0 kg DM (R1) rising to 7.7 kg DM (R2–R4) versus 7.9 kg DM on average (R5–R10). Calculations using the broken line model and the quadratic model show that the optimal Co supply for maximum growth is 0.12 mg/kg dietary DM and for maximum feed intake, 0.16–0.18 mg Co/kg dietary DM. After taking further biochemical criteria into account (Stangl et al. 2000), a level of 0.20 mg/kg dietary DM is recommended as an adequate Co supply for growing cattle.  相似文献   

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