Fatty acid profile of ewe's milk infected with Staphylococcus spp.

BACKGROUND: Mastitis in sheep caused by Staphylococcus spp. is a serious concern for dairy farming. AIMS: The objective of this study was to evaluate the impact of the intramammary infection (IMI) caused by Staphylococcus spp. on the lon g-chain fatty acid profile and composition of ewe's milk. METHODS: The experiment was conducted in a herd of Zoslachtena Valaska sheep. Half-udder milk samples were collected from 20 weight-matched sheep at the peak of their first or second lactation. The basic physicochemical composition of milk, somatic cell count (SCC), Staphylococcus spp. infection, and total bacterial contamination (TBC) were determined. The fatty acid profile of the milk fat was determined using gas chromatography. RESULTS: The SCC in milk infected with Staphylococcus spp. was 3.25 times higher (P<0.01) than that in the uninfected milk samples. The content of lauric acid (С12:0) was higher (P<0.05) in the milk fat of infected ewes. A significant increase (P<0.05) in the share of linoleic acid (C18:2n6t), arachidonic acid (C20:4n6), and a decrease (P<0.01) in the vaccenic acid (C18:1n7t) were observed in the milk collected from ewes infected with Staphylococcus spp.. Staphylococcus spp. infection increased the ratio of n-6 to n-3 polyunsaturated fatty acids. CONCLUSION: Changes in the fatty acid profile of milk caused by Staphylococcus spp. infection decrease the value of ewes' milk as a health-promoting product.

Comparison of biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis strains isolated from sheep milk using three diagnostic methods.

In this study we investigated 24 strains of Staphylococcus aureus and 33 strains of Staphylococcus epidermidis isolated from milk of sheep with clinical mastitis, for their ability to form biofilms. Three methods for the determination of a biofilm were used. When evaluating the growth on Congo Red agar (CRA), 79.2% S. aureus strains and 72.7% S. epidermidis strains were positive for biofilm formation. The quantitative method of biofilm detection on a Microtitre Plate (MTP) revealed positive results for 75.0% of S. aureus samples and 75.8% for S. epidermidis samples. Using PCR method for determination of the presence of genes that affect formation of biofilms, the most frequently determined genes were eno in both S. aureus (18/24; 75.0%) and S. epidermidis strains (20/33; 60.6%). The genes icaAB and ebpS were detected in both S. aureus and S. epidermidis strains, and similarity between these strains was 12.5% - 15.1% and 4.2% - 6.0%, respectively. The bap was recorded only in S. epidermidis (3.0%). Statistical comparison of the level of biofilm formation was performed using Chi square test. There were no statistically significant differences in the amount of biofilm formation between two methods for detection of biofilm CRA and MTP (p>0.05). Comparison of all six monitored parameters showed no dependence of characteristics of the tested strains S. aureus and S. epidermidis at significance level α = 0.05. Biofilm formation by the bacteria isolated from 57 cases of clinical mastitis in sheep was confirmed. Sensitivity and specificity of the CRA method for S. aureus were 94.44% and 66.66%, respectively, and for S. epidermidis 92.0% and 87.5%, respectively. Both CRA and MTP methods can be recommended for the detection of biofilm production by S. aureus and S. epidermidis strains isolated from milk of sheep with clinical mastitis.

An effect of mammary gland infection caused by Streptococcus uberis on composition and physicochemical changes of cows' milk.

An effect of mammary gland infection caused by Streptococcus uberis on the changes in cows' milk composition and its physicochemical properties was examined. The study was conducted in the herd of Slovak Pied breed cattle (with a share of HF blood), in 2nd and 3rd lactation, after 4th month of milking. Milk samples were collected from a quarter milking. The samples were subjected to microbiological analysis, basic milk composition, total bacteria count, somatic cell count and physicochemical properties were examined. Also analyses of protein fractions share and fatty acids profile were conducted. An effect of bacterial infection of the mammary gland bring an increase (P<0.01) in somatic cell count was observed in this study. Milk samples contaminated with S. uberis were characterized by higher (P<0.05) total bacteria count and total protein compared to milk samples collected from non-infected mammary gland. The level of κ-casein was significantly (P<0.05) decreased in cows with subclinical mastitis caused by S. uberis. Significant (P<0.05) reduction in the share of C13:0 acid, and an increased level of C18:0, C18:1n7t and CLA were observed in milk contaminated with S. uberis compared to healthy cows' milk. It should be concluded that S. uberis causes the increase in total bacteria count, SCC and the decrease in κ-casein level, which significantly affects deterioration of technological quality of cows' milk.

Effects of udder infections with Staphylococcus xylosus and Staphylococcus warneri on the composition and physicochemical changes in cows milk.

The aim of this study was an evaluation of the effects of two species of coagulase negative staphylococci (CNS), Staphylococcus xylosus and Staphylococcus warneri, on the changes in technological parameters of cows' milk. The study was conducted in a herd of Slovak Pied cattle breed (with share of HF blood). Based on the performance results from three subsequent months, cows in the 2nd and 3rd lactation with SCC up to 200 thousand/ml (8 heads, 32 quarters), and above 800 thousand/ml (8 heads, 32 quarters), after the 4th month of lactation, were selected. The samples were subjected to microbiological analysis, total bacteria count, somatic cell count; basic milk composition and physicochemical properties were also examined. The research has found the impact of bacterial infection on the increasing (p<0.05) of the number of somatic cells and a decrease (p<0.01) in protein levels in milk due to both types of staphylococci. There was a significant (p<0.05) reduction in C8: 0, C10: 0 and the total amount of saturated fatty acids in the milk of the infected cows in comparison to the healthy ones. The research also revealed higher (p<0.01) levels of C14: 0 and C20: 1 in milk from the healthy cows.

Effect of parenteral administration of selenium and vitamin E on health status of mammary gland and on selected antioxidant indexes in blood of dairy cows.

This study focuses on the effect of parenteral administration of Selenium (Se) and vitamin E on concentration of Se in plasma and the activity of glutathione peroxidase (GPx) in the blood of dairy cows during peripartal period and their effect on the reduction of clinical mastitis. From a 220 individuals Holstein herd in a two-four lactation-gestation cycle the control group (C), 1st (D1) and 2nd (D2) experimental group were selected. Every group consisted of 15 cows in the last phase of the pregnancy. All cows were fed with the diet containing 0.1 mg of Se per kg/DM. The blood samples from vena jugularis were collected approximately 21 days before calving (control sampling), 3 days, 12 days and 21 days after calving. On the day of control sampling and 12 days before calving in D1 group, cows were injected subcutaneously in the sprescapular region with preparation Selevit inj. a.u.v. at the doses of 48.4 mg/head of Se, and 550 IU/head of alpha-Tocoferol (alpha-Toc). In D2 group, cows were injected by the same preparation only on 21th day before calving with the same doses of Se and alpha-Toc. The increase in the concentration of Se in the plasma and activity GPx in blood in D1 group on the 3rd day and 12th day after calving were determined. Increase in plasmatic concentrations alpha-Toc on 3rd day after calving and reduction of occurrence of clinical mastitis (13.3%) as compared with control group were found.

Limited genetic diversity of Aerococcus viridans strains isolated from clinical and subclinical cases of bovine mastitis in Slovakia.

The Aerococcus viridans isolates from bovine mastitis in Slovakia were isolated and characterized by classical microbiological and biochemical, and molecular techniques including IGS-PCR and rep-PCR, ARDRA and 16S rDNA gene sequencing. The substantial variability of antibiotic resistance patterns was observed. The majority of strains were resistant to beta-lactam antibiotics, the resistance to tetracycline was observed in 3 tested strains, resistance to lincomycin was found in 4 strains and practically all tested strains were sensitive to neomycin and ciprofloxacin. While variable at a phenotypic level, no significant genetic variability among A. viridans isolates was detected by molecular DNA based methods. The data obtained suggest that a few A. viridans strains spread among cow's population in Slovak farms.

[Dynamics of changes in the cytological picture of vaginal smears and circulating ovarian hormones during the puerperal period in ewes]. / Dynamika zmien cytologického obrazu posvového steru a ovariálnych hormónov cirkulujúcej krvi v puerperálnom období bahníc.

A postparturient period is characterized by low basal secretion of adenohypophysis gonadotropins with the following appropriate changes in ovarian hormones and their response to the morphology of vaginal epithelium. In this study the dynamics of the cytological picture of vaginal swabs and ovarian hormones 17 beta-oestradiol (E2) and progesterone was investigated in the puerpery of ewes. The objective was to obtain and extend the knowledge of cytological changes in vaginal epithelium and levels of ovarian hormones of ewes after parturition and of their relationships from the first several days after lambing until the 51st day of the period of observation. Vaginal swabs for vaginal cytology were taken from nine ewes on days 1, 4, 7, 14, 17, 21, 25, 34, 42 and 51 after parturition. These swabs were fixed in ether-alcohol 1:1, stained according to the Faltínová-Zidovský method, embedded in Canada balsam and evaluated by differentiation of cells according to Luksh (1953). Blood samples for E2 and P4 determinations were taken from the jugular vein in the same intervals as vaginal swabs. The serum was centrifuged and stored at -18 degrees C until use. E2 and P4 concentrations were determined radioimmunologically, using kits RIA-test ESTRA and RIA-test PROG from URVJT Kosice. A statistically significant decline (P < 0.05) of percentual representation of basal and parabasal cells (Fig. 1, Tab. I) on day 7 after lambing was replaced by their multiplication from day 14 reaching the values of 66.07 +/- 3.95 on day 42. A statistically significant decrease in intermediary flat cells (Fig. 2, Tab. II) was observed on days 14 (P < 0.001), 34 and 42 (P < 0.01; P < 0.001), in comparison with the first day after lambing. An evaluation of intermediary convoluted cells revealed their highest percentage on days 1 and 17 after parturition (34.65 +/- 4.77-20.62 +/- 12.57) and their decline to values in the range of 6.77 +/- 1.46-7.66 +/- 2.25 on the remaining days of the period of observation. Percent occurrence of superficial flat cells (Fig. 3, Tab. I) ranged from 3.9 +/- 1.10 to 10.63 +/- 7.23 from day 1 to day 51 after lambing. The lowest percentual representation (1.32 +/- 0.79-4.10 +/- 1.89) was recorded for superficial convoluted cells. Multiplication of the evaluated cells was observed, reaching the highest but insignificant representation (P > 0.05) on day 25 of postparturient investigation: 4.10 +/- 1.89 (Fig. 3, Tab. I). 17 beta-oestradiol (E2) concentrations were compared to the -1st day before parturition, when its values varied at the level of 2.45 +/- 0.64 nmol/l serum.(ABSTRACT TRUNCATED AT 400 WORDS)

[Dynamics of changes in the serum levels of cholesterol, thyroid and ovarian hormones in the postpartum period in ewes]. / Dynamika zmien koncentrácie cholesterolu, tyroidných a ovariálnych hormónov krvného séra v postpartálnom období bahníc.

Postparturient anoestry, spontaneously changing over to seasonal anoestry, represents an important reserve of full utilization of the reproductive potential of sheep. In spite of the fact that the length of gestation in sheep only amounts to 148 days (+/- 5 days), inability of most sheep to enter the cycle during the spring season acts as a factor limiting the number of lambings--and at the same time production of lambs--to one lambing per year. In order to obtain more detailed knowledge of hormonal conditions in sheep puerpery, the presented work was directed at the study of dynamic changes in concentrations of thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) and cholesterol (Chol) in the blood serum of ewes and at their mutual correlative dependences between the 36th hour and the 51st postparturient day. The observation was carried out in nine nursing ewes of the Slovak Merino breed, with average weight 40-50 kg, lambed in January and February. Blood was sampled by means of jugular vein puncture 14 days (-14th day) before parturition (a. p.), up to 36 h after parturition (p. p.) and on day 4, 7, 14, 17, 21, 25, 34, 42 and 51 p. p. In the period from the 36th h to day 21 p. p., concentrations of T4 (Tab. I, Fig. 1) showed a decreasing tendency compared to the starting -14th day (69.55 +/- +/- 0.12 nmol.-1) with the exception of a temporary increase on the 7th day p. p. The lowest values were recorded on days 4 and 21 p. p. (45.66 +/- 21.61 nmol.l-1, P less than 0.05 and 54.89 +/- 11.06 nmol.l-1, P less than 0.05, resp.). An increase of these values to the starting level was observed between days 25 and 51 p. p. Compared to the values on -14th day (0.76 +/- 0.22 nmol.l-1), a significant increase of T3 concentrations (Tab. I, Fig. 2) was recorded at the 36th h and on days 4 and 7 p. p. with the highest values (1.48 +/- +/- 0.34 nmol.l-1, P less than 0.001) at 36 h p. p. After the temporary decrease between days 14 and 21 p. p. its concentrations showed a constantly rising tendency statistically significant on days 34, 42 and 51 p. p., compared to the -14th day (P less than 0.05). Concentrations of E2 (Tab. I, Fig. 3) reached the values of 0.44 +/- 0.41 nmol.l-1 on the -14th day.(ABSTRACT TRUNCATED AT 400 WORDS)

[Biometric parameters of the uterus and ovaries in sheep after administration of Depotocin inj. Spofa in early puerperium]. / Biometrické parametre maternice a vajecníkov po aplikácii Depotocinu inj. Spofa v ranom puerpériu oviec.

Objectivisation of the physiological course of puerpery and control of involution processes of uterus represent topical questions of an increased frequency of lambing. Our study was directed at the determination of the weight, length of body and horns of uterus as well as of the weight, length, width and height of ovaries, following the administration of carbetocin (Depotocin inj. Spofa), in the puerperal period of Slovak Merino sheep. The study was aimed at obtaining objective biometric data on uterus and ovaries and recording the influence of carbetocin on the involution of uterus and ovaries of sheep. Thirty ewes, divided into two groups, were included in the experiment. The animals of the experimental group (n = 15) were subjected to treatment with carbetocin (Depotocin inj. Spofa) at the amount 2 x 0.07 mg. The first dose was applied intramuscularly (i. m.) on the 2nd day after parturition and the second dose was injected subcutaneously (s.c.) on the 4th day after lambing. The second group (n = 15) served as a control. Three ewes (n = 3) were bled on each of the following days: 1, 7, 17, 25 and 34 after parturition. After bleeding the sexual organs were removed by excision and their weight and the length of the body and horns of uterus and of ovaries was determined. The number and size of follicles were determined on the surface of ovaries. The weight of uterus body showed a declining tendency in sheep of the control group with a statistically significant decrease from the 17th till the 34th day after parturition (P less than 0.01). Its weight varied from 56.0-14.6 to 5.2-0.3 g in the above-mentioned time interval. The experimental group showed a statistically significant decrease in weight as early as on the 7th day after lambing compared to the 1st day after parturition, down to the values 185.66-38.91 g (P less than 0.05). The decrease in the weight of uterus body recorded on day 17 (106.56-41.08 g) was less pronounced than in the control group. The final average weight of the body of uterus on the 34th day after parturition was 41.36-8.52 g, that means higher than in the control group (5.2-0.3 g). The weight of gravid horns in the experimental group declined significantly as early as on the 7th day after parturition to the average weight of 60.89-9.45 g and reached 9.86-3.49 g on the 34th day.(ABSTRACT TRUNCATED AT 400 WORDS)

[Biometric parameters of the uterus, ovaries and levels of 17 beta-estradiol (E2) after delivery in sheep]. / Biometrické parametre maternice, vajecníkov a koncentrácie 17 beta-estradiolu (E2) po pôrode oviec.

Biometric changes of uterus, ovaries, follicles and 17 beta-oestradiol (E2) concentrations were investigated in 15 lambing ewes of the Slovak Merino breed in the puerperal period. The sex organs were excised immediately after bleeding from ewes slaughtered on days 1, 7, 17, 25 and 34 post partum (p. p.). Biometric parameters of the body and horns of uterus were measured by a calliper. The ovaries were weighed on an analytical balance, their length, width and height were measured at the same time. The size and number of follicles were determined on the ovary surface. The blood for E2 detection was collected from vena jugularis three and one day before delivery (days -1, -3). Blood samples were also collected after delivery on days 1, 7, 17, 25 and 34. E2 concentrations in the blood serum of ewes were determined by RIA-test-ESTRA kits, designed in one institute at Kosice. The highest weight of uterus body in the test ewes was recorded on day 1 p. p. In the following days the weight of uterus body had a decreasing trend. There were significant differences in the weight of uterus body from day 17 to day 34 p. p., in comparison with the first day after lambing (P less than 0.01). A significant decrease in the length of uterus body was observed from day 17 to day 34 of observation (P less than 0.01; P less than 0.001). An increase in the length of a nongravid horn, observed on day 7 p. p., was followed by a gradual decrease until day 34, similarly like in its weight. No statistically significant differences were found out in the ovary length, width and height. Neither were any greater changes recorded in the weight of ovaries from day 1 to day 34 after delivery. The highest number of small structures (28) observed on day 7 p. p. in the ipsilateral ovary was decreasing in the course of puerperium and the number of follicles larger than 2, 4 and 5 mm was increasing. The highest concentrations of E2 were not recorded on day -1 before delivery. The significantly lowest concentrations of E2 were recorded on day 25 p. p. The above-mentioned results are preliminary and they enlarge the knowledge of biometric parameters of uterus, ovaries, follicles and E2 concentrations after delivery in ewes.

[The effect of steroidal dominance on cAMP, cGMP, progesterone and 17 beta-estradiol levels in the fluid of the largest follicle]. / Vplyv steroidnej dominancie na koncentrácie cAMP, cGMP, progesterónu a 17 beta-estradiolu v tekutine najväcsieho folikulu.

Concentrations and mutual correlations of the cyclic adenosin monophosphate (cAMP), quanosin monophosphate (cGMP), progesterone (P4) and 17-beta-estradiol (E2) were studied in the fluid of the largest follicles in cows, in dependence on the steroid dominance: estrogen-dominant (ED), progesterone-dominant (PD) follicles. Mean cAMP and cGMP concentrations in the follicular fluid in the estrogen-dominant follicles were significantly higher than in the progesterone-dominant follicles; in both cases at P less than 0.01. Significant positive correlation between cAMP and cGMP at P less than 0.001 was stated in the evaluation of the correlations. The cAMP and cGMP concentrations were in significantly negative correlations with the P4 concentration at P less than 0.05, or P less than 0.01 and in significantly positive correlations with the E2, at P less than 0.05. The stated correlations suggest a close mutual relation between cyclic nucleotid and E2, or P4 when the follicles' quality changes.

[Changes in blood levels of progesterone, triiodothyronine and thyroxine and the results of quantitative histological analysis of the placentoma and corpus luteum in cows after prolonged labor]. / Zmeny koncentrácie progesterónu, trijódtyronínu a tyroxínu v krvi a výsledky kvantitatívnej histologickej analýzy placentómu i zltého telieska kráv po protrahovanom pôrode.

Changes in the cell structure of the placentoma and the corpus luteum were subjected to quantitative histological investigation, parallel with the examination of the concentrations of progesterone (P4), triiodotyronine (T3) and tyroxin (T4) during parturition (Oth hour) and two and six hours after parturition. The hormone concentrations were determined by the RIA method. The results of the quantitative histological analysis of the placentomae and the corpus luteum suggest that when the placenta is retained there is a significantly higher number of maintained epithelial cells in the placentoma crypts and a higher number of unchanged small, dark and large, light lutein serraetion cells in the biopsy of the corpus luteum during the period under investigation. The morphological finding significantly correlates with higher concentrations of P4 in the blood of the cows with retained placenta, as compared with those whose placenta was not retained. It can be derived from the pattern of changes in T3 and T4 concentrations, compared with P4 and with the histological finding, that there is a functional relationship between the placentoma, corpus luteum, and the thyroid gland.

[Radioimmunologic determination of progesterone and rectal ovarian palpation in embryonic death in cows]. / Rádioimunologické stanovenie progesterónu a rektálna palpácia ovárií pri embryonálnej mortalite kráv.

Repeated radio-immunological assays of progesterone in milk and ovary rectal palpation were used for indirect determination of embryonal mortality in cows. Milk sampling and rectal examination were made in the insemination period and then in two- to three-day intervals, mostly from the 21st day after insemination till the early pregnancy determination made after the 42nd day on the basis of the double wall phenomenon. Observation was made in 185 animals from two herds. Embryonal mortality was found in 9.06% out of 289 evaluated inseminations, which prolongs the oestral cycle over 25 days. The monitoring corpus luteum function in connection with rectal ovary palpation supplemented by oestrus, ovulation and insemination control enable a more objective indirect diagnosis of embryonal losses prolonging the oestral cycle.

[Pregnancy in dairy cows in various times of the year in relation to thyroxine and triiodothyronine levels]. / Zabrezávanie dojníc v róznych rocných obdobiach vo vztahu ku koncentráciám tyroxínu (T4) a trijódtyronínu (T3).

Conception of dairy cows was investigated in relation to changes in thyroxine (T4) and triiodothyronine (T3) concentrations in March (n = 15), June (n = 10) November (n = 7) after oestrus synchronization by cloprostenol (Oestrophan Spofa) at a dose of 0.05 mg per head. The cows were inseminated from 8.00 to 9.00 o'clock a.m. Blood was taken from 9.00 to 10.00 a.m. from v. jugularis on the day of Oestrophan treatment (-3rd day), on the day of insemination (day 0), and on the 6th and 21st day after insemination. The lowest percentage of pregnant cows (26.67%) was recorded after the March insemination, the highest (50.0%) after the June insemination. 42.86% of cows became pregnant in November. Concentrations T4 in pregnant animals on the day 0 of March insemination were 67.55 +/- 16.95 nmol.1-alpha of serum. Nonsignificant decrease to value 65.60 +/- 10.06 and 49.33 +/- 17.47 nmol.l-1 of serum were observed on the day of June and November insemination. In T3 concentrations an average decrease from the values of 2.53 +/- 0.67 nmol.l-alpha on day 0 of the March insemination to 1.48 +/- 0.67 nmol.l-alpha on day 0 of the June insemination was observed, as well as a significant decrease to 0.80 +/- 0.45 nmol.l-1 of serum (P less than 0.05) on the day of the November insemination. Considering the results we suppose that the conception of dairy cows has an indirect relationship to thyroid hormones.

[Changes in surface follicles and ovarian weight in testing for responsiveness in dairy cows after induction of superovulation using PMSG and cloprostenol]. / Zmeny povrchových folikulov a hmotnosti vajecníkov pri testovaní responzibility dojníc po indukcii superovulácie PMSG a cloprostenolom.

We evaluated the ovaries of 34 cows cross-bred of the Slovak Pied and Lowland Black-pied breeds which were culled and intended for slaughter during the winter type of feed rations. For superovulation treatment we used PMSG in the preparation Serum Gonadotropin (Bioveta, Nat. Ent., Ivanovice na Hané) and cloprostenol in the preparation Oestrophan inj. Spofa. We weighed the excised ovaries, fixed them in formalin 10% and made a quantitative evaluation of the surface follicles and differentiated them into recruited and selected or dominant follicles. We determined the concentration of 17 beta-estradiol and testosterone with the aid of the 3H RIA set from the firm Sorin after extraction by diethylether with separation of free and bound hormone with active charcoal. 72 hours after the giving of cloprostenol 43% reacted positively to superovulation treatment and after seven days a 50% positive response was recorded. After a dose of 2000 i. u. of PMSG (n = 6) embryo was obtained, whereas after 3000 i. u. of PMSG (n = 8) we flushed out eight embryos, of which four zygotes were suitable for transfer. After a higher dosage of PMSG there was an increase in the average weight of the ovaries, in right-hand ovaries significantly with P less than 0.05. After super-ovulation treatment the concentration of 17 beta-estradiol (E2) in the follicular fluid from follicles seven days after insemination was found to be so low as to be below the limit of detection, with the exception of four samples (mean = 8.60 nmol.l-1). The greatest concentration of E2 was from animals (n = 5) 72 hours after the giving of cloprostenol--1099.61 nmol.l-1) of follicular fluid. The concentration of testosterone was lower in the follicles of untreated cows in the follicular phase (mean = 5.92 nmol.l-1) compared with the follicles of super-ovulated animals the seventh day after insemination (mean = 14.12 nmol.l-1). The number of recruited and especially selected surface antral follicles 72 hours (n = 7) after the giving of cloprostenol and seven days (n = 8) after insemination was significantly higher in the group of brood cows reacting positively to superovulation in comparison with the animals which did not respond. It appears that the simultaneous monitoring of hormonal and morphological changes in the follicular system will help in objectivising the evaluation of the functional activity of stimulated follicles.

[The effect of beta-carotene on thyroxine and cholesterol levels in pregnant heifers before and after parturition]. / Vplyv beta-karoténu na koncentrácie tyroxínu a cholesterolu u telných jalovíc pred pôrodom a po pôrode.

Thyroxine (T4) and cholesterol concentrations and their dynamic changes and differences were studied in 20 pregnant heifers 10 days before calving until 56 days after calving. Ten control heifers were fed the feed ration for pregnant heifers according to Czechoslovak Standard CSN 46 7070. The feed ration given to another ten (experimental) heifers was fortified with 300 mg of synthetic beta-carotene per head/day within the period of five months before insemination, during pregnancy and till the 56th day after parturition. As suggested by the regression function of straight line, no obvious differences were recorded in the dynamic changes of T4 before parturition and during the first days after parturition. T4 concentrations had a generally descending tendency in both groups, the lowest values being recorded in the 48th hour in the experimental group and the 24th hour in the control. A marked increase of T4 concentrations with the values significantly higher in the control group than in the experimental group was observed between the 21st and 35th day after calving. A medium increase of cholesterol concentrations was found in the heifers given rations fortified with beta-carotene. No significant differences in cholesterol concentrations were observed between the two groups, except in the 72nd hour and the seventh day. Significant T4: cholesterol correlations were recorded in the experimental animals in the first and second hours, on the 42nd day (P less than 0.05), and in the 72nd hour (P less than 0.001); in the control group these observations were made the seventh day before calving and in the sixth hour and on the 14th, 21st and 56th days (P less than 0.05) after calving. It is inferred from the results that beta-carotene interferes with the activity of the thyroid gland and the production of its hormones, and that the increases or decreases of the activity of this gland, caused by beta-carotene, influence the metabolism of cholesterol in the body.

[Levels of thyroxine, beta carotene and vitamin A during successful and unsuccessful insemination of heifers]. / Koncentracie tyroxínu, beta karoténu a vitamínu A pri úspesnej a neúspesnej inseminácii jaloviíc.

We studied the concentrations of thyroxine (T4), beta-carotene and vitamin A (vit. A) on the day (zero-th day) of the first successful and unsuccessful insemination of 63 heifers that were administered feed rations balanced according to the Czechoslovak standard CSN 46,7070, housed all the year round, inseminated at uniform time (8:00-9:00 a. m.) and with blood samplings at uniform time (10:00-12:00 a. m.). In the repeat-breeder heifers during the first insemination the above parameters were determined in the same conditions on the day of their second, or third successful and also unsuccessful insemination; the changes relevant to the first insemination were evaluated. In relation to the day of the first successful insemination, we recorded a significant increase in T4 concentration (P less than 0.001; P less than 0.001) on the day of the second, or third successful inseminations. During the second insemination we recorded significantly lower T4 concentrations in the cows which had failed to be inseminated in comparison with successfully inseminated cows; these concentrations did not differ significantly from T4 concentrations in the heifers that failed to become pregnant in the first insemination. Parallelly with the rise in T4 concentration, beta-carotene concentrations also increased during the second and third inseminations (P greater than 0.05). No difference was recorded in beta-carotene concentrations after the first and second unsuccessful inseminations.(ABSTRACT TRUNCATED AT 250 WORDS)

[Concentrations of thyroxine, beta carotene, vitamin A and pregnancy in heifers after administration of beta carotene]. / Koncentrácie tyroxínu, beta karoténu, vitamínu A a zabrezávanie jalovíc po prívode beta karoténu.

Serum concentrations of thyroxine (T4), beta-carotene (beta K), vitamin A and conception after the first insemination on the zero, sixth and 21st day were studied in 63 heifers fed synthetic beta K supplement in groups I to IV at stanchion housing and low-carotene diet. The following amount of beta K was supplemented per head/day: I--0 mg (control, n = 17), II--100 mg (n = 16), III--200 mg (n = 14) and IV--400 mg (n = 16). The parameters were evaluated separately according to groups and conception. By comparing the T4 concentration between experimental groups and control, separately in non-gravid and gravid animals, a significant increase (P less than 0.05) was determined only on the zero day in the fourth group. At the same time, in the fourth group, in comparison with the others, insignificantly lower T4 values were recorded in non-gravid animals. beta K values on the zero day in gravid animals increased in a direct proportion to the higher supplement (P less than 0.05; P less than 0.01; P less than 0.001); in non-gravid animals the increase was slower (P less than 0.05; P less than 0.05; P less than 0.01), but differences in relation to gravidity were not significant. An increase of beta K had no significant effect on serum concentrations of vitamin A. Differences between groups as far as conception was concerned were insignificant. It follows from the results that increasing rates of beta K, with the exception of serum concentrations, had no significant effect on other parameters. Higher concentrations of T4 and a slower increase of beta K in non-gravid animals, however, point at mutual co-operation relation and its positive effect on conception in animals.

[Correlation between the thyroxine, 17-beta-estradiol and luteinizing hormones in the systemic circulation and the rectal and vaginal temperature in heifers and cows after administration of cloprostenol]. / Korelácia medzi tyroxínom, 17-beta-estradiolom, luteinizacným hormónom v systémovom obehu a rektálnou i vaginálnou teplotou jalovíc a kráv po podaní cloprostenolu.

Changes in the concentration of 17beta-oestradiol (E2) and luteinizing hormone (LH) and in the rectal and vaginal temperatures (RT and VT) were studied along with the changes in thyroxine concentration (T4) in three cows and three heifers in the luteal stage of the cycle; the animals had been intramuscularly treated with 2 ml Oestrophan (cloprostenol). The closeness of the correlation between T4 and the remaining parameters under study was determined by the calculation of the correlation coefficient and statistical significance. The concentrations of T4 before and during cloprostenol administration were high in comparison with the post-treatment levels. E2 concentrations at cloprostenol administration time were much higher than those recorded before administration. After treatment the concentrations of T4 and E2 sank. The first E2 peak, recorded in the 44th hour, was immediately followed by a marked drop of E2 as well as T4, the lowest values of both being recorded in the 52nd and 56th hour. The second peak of E2 in the 60th hour was followed by a slow but steady decrease. The rise of the concentration of T4 after the 56th hour was slow and reached the peak in the 74th hour; after a partial decrease no further marked changes in concentrations were recorded. LH concentrations rose at a slow rate to reach the peak in the 64th hour. After a rapid decline they reached the pre-peak value in the 70th hour. The lowest RT and VT levels were recorded in the 54th and 94th hour. It can be assumed on the basis of the behaviour of the hormones and the evaluation of their correlations that thyroidal hormones are involved in the stimulation of the synthesis of ovarial oestrogens which tend, after their synthesis, to eliminate from circulation the T4 as well as their own levels and thereby to influence (as feedback) the stimulation of T4 synthesis, their own synthesis, and LH.