Gyula Huszenicza

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.

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.

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.

ADRENOCORTICAL AND THYROID FUNCTION, HORMONE AND METABOLITE PROFILES AND THE ONSET OF OVARIAN CYCLICITY IN DAIRY COWS SUFFERING FROM VARIOUS FORMS OF KETOSIS

The involvement of adrenocortical and thyroid hormones in the pathogenesis of ketosis, as well as the ovarian consequences of this metabolic disorder, were studied in _2 parity cows (n=199) in 3 large scale dairy herds. To compare the plasma/serum concentrations of certain hormones Scortisol, thyroxin (T4), triiodothyronine (T3), insulin, insulin-like growth factor-1 (IGF-1)¹ and metabolites Sglucose (G), acetoacetic acid (ACAC), βOH-butyrate (BHB), non-esterified fatty acid (NEFA), trigliceride (TG), total cholesterol (TCh)¹, and the activity of aspartate aminotransferase (AST), blood samples were taken 1 to 3 days after calving and again 4 times 7 days apart. The ACTH-challenged cortisol responsiveness and the TRH-induced T4/T3 increase were determined between days 1 to 3 and again between days 28 to 35. The resumption of ovarian cyclicity was followed up by individual progesterone (P4) profiles based on milk samples taken 3 times a week for about 80 to 85 days. BHB level of 1 mmol/L was estimated as a border line between hyper- (>1 mmol/L) and normoketonaemic (<1 mmol/L) conditions. Five different ketone patterns were distinguished: (1) non-ketotic (n=98; normoketonaemia in all samples), (2) early type ketosis (n=45; hyperketonemia was detected only in the first week after calving), (3) late type (lactational) ketosis (n=11; after a normoketonaemic period increasing hyperketonaemia was detected in the 5th, or in the 4th and 5th weeks), (4) temporary ketosis (n=11; hyperketonaemia was detected for 1-2 weeks in the 2nd and 3rd or in the 3rd and 4th weeks); (5) long-lasting ketosis (n=34; hyperketonaemia has been detected since calving for 4 to 5 weeks or until dying / emergency slaughtering). Simultaneously with the hyperketonaemic stage increased NEFA, ACAC, depressed TCh, glucose and decreased insulin, IGF-1, T4 and T3 concentrations were detected in almost all the cases. Obvious metabolic and endocrine alterations were found, however, only in long-lasting ketosis. The TRH-stimulated T4 and T3 responses remained almost unaffected proving intact thyroid function in early and late type as well as in temporary ketosis. Depressed thyroid response and delayed onset of cyclic ovarian function were detected only in cases of long-lasting ketosis. The cows characterized by lower than normal (<mean-SD of non-ketotic cows) ACTH-stimulated cortisol response on days 1-3 after calving showed poorer chance for spontaneous recovery. There was a significant negative correlation between the IGF-1 level in the 1st week after calving and the duration of the postpartum acyclic period. In late type (lactational) ketosis the cessation of ovarian cyclicity was the most characteristic genital malfunction.

Milk production, peripartal liver triglyceride concentration and plasma metabolites of dairy cows fed diets supplemented with calcium soaps or hydrogenated triglycerides of palm oil

The aim of the study was to test the effect of rumen-inert fat supplements of different chemical forms or containing different unsaturated/saturated (U/S) fatty acid contents on milk production, milk composition and liver and blood metabolic variables of high-yielding dairy cows in the peripartal period. Thirty Holstein-Friesian dairy cows were divided into three equal groups and fed a corn silage-based diet, without fat supplementation (control) or supplemented with 11.75 MJ NEl per day of calcium soaps of palm oil fatty acids (CAS; U/S=61/39) or with 11.75 MJ NEl per day of hydrogenated palm oil triglyceride (HTG; U/S=6/94). Each diet was fed from 25+/-2 d prior to the expected calving to 100+/-5 d post partum. Compared with the control, both CAS and HTG supplementation resulted in an increase of the average milk yield. Milk fat content and fat-corrected milk yield were higher in the HTG group but lower in the CAS group than in the control group. In all groups liver triglyceride concentrations (TGL) increased from 15 d prepartum to 5 d post partum, and then decreased thereafter. At 5 d TGL was lower in the HTG group than control or CAS cows. No significant differences were detected in TGL among dietary treatments at 15 d prepartum and 25 d post partum. Higher plasma glucose and insulin and lower non-esterified fatty acids and beta-hydroxybutyrate concentrations and aspartate aminotransferase activity were measured in the HTG group than in the control or CAS groups at 5 d or 25 d post partum. Our results show that HTG may provide a better energy supply for high-yielding dairy cows in negative energy balance than CAS around calving.

Seasonal fertility differences in synchronised dairy cows: ultrasonic, metabolic and endocrine findings.

The aim of this study was to identify relationships among seasonal differences of fertility, metabolic parameters and appearance of irregular luteal forms in high-yielding dairy cows. Holstein-Friesian cows were put on the Provsynch regimen in winter (n = 10) and in summer (n = 10). Blood sampling (starting 35 days post partum) and rectal ultrasound examinations (starting post insemination) were carried out once a week in each examination period. Metabolic [plasma nonesterified fatty acid (NEFA) and beta-hydroxybutyrate (BHB) levels, ferric reducing ability of plasma (FRAP) and serum beta-carotene] and endocrine parameters [plasma thyroxine (T4), triiodothyronine (T3), insulin-like growth factor (IGF-I) and insulin levels] were measured. In summer, two cows were excluded from the study because of metritis and none of the remaining animals became pregnant, but 6 of the 8 cows had irregular luteal forms (ILF) on their ovaries. In winter, one cow was excluded because of metritis and 6 of the 9 cows became pregnant, while 2 of the 3 open cows had irregular luteal forms. In summer the mean plasma NEFA and BHB concentrations were significantly higher, while serum carotene and plasma IGF-I concentrations were significantly lower than in winter. The high plasma NEFA concentration found in summer seemed to be in association with the lower body condition score (BCS) caused by depressed appetite. In conclusion, statistical analysis supports the hypothesis that increased plasma NEFA and BHB and decreased plasma IGF-I concentrations may result in reduced fertility in summer. These changes may be associated with the more frequent appearance of ILFs and probably have a negative effect on ovarian function and/or oocyte quality.

Subsequent effect of subacute T-2 toxicosis on spermatozoa, seminal plasma and testosterone production in rabbits

Pannon White (n=12) male rabbits (weight: 4050 to 4500 g, age: 9 months) received 2 ml of a suspension containing purified T-2 toxin by gavage for 3 days. The daily toxin intake was 4 mg/animal (0.78 to 0.99 mg/kg body weight (BW)). Control animals (n=12) received toxin-free suspension for 3 days. Since a feed-refusal effect was observed on the second day after T-2 administration, a group of bucks (n=10) were kept as controls (no toxin treatment) but on a restricted feeding schedule, that is, the same amount of feed was provided to them as was consumed by the exposed animals. On day 51 of the experiment (i.e. 48 days after the 3-day toxin treatment), semen was collected, and pH, concentration, motility and morphology of the spermatozoa, as well as concentration of citric acid, zinc and fructose in the seminal plasma, were measured. After gonadotropin-releasing hormone (GnRH) analogue treatment, the testosterone level was examined. One day of T-2 toxin treatment dramatically decreased voluntary feed intake (by 27% compared to control, P<0.05) and remained lower (P<0.05) during the first 2 weeks after the withdrawal of the toxin. BW of the contaminated rabbits decreased by 88% on days 17 and 29 compared to controls (P<0.05). No effect of toxin treatment was detected on pH and quantity of the semen or concentration of spermatozoa. The ratio of spermatozoa showing progressive forward motility decreased from 65% to 53% in the semen samples of toxin-treated animals compared to controls (P>0.05). The ratio of spermatozoa with abnormal morphology increased (P<0.05) in the ejaculates collected from the toxin-treated animals. T-2 toxin applied in high doses decreased the concentration of citric acid in seminal plasma (P<0.05). No effect of T-2 toxin on the concentrations of the other seminal plasma parameters (fructose and zinc) was observed. T-2 toxin decreased the basic testosterone level by 45% compared to control (P<0.01) and resulted in lower (P<0.05) GnRH-induced testosterone concentration. Feed restriction, that is, less nutrient intake, resulted in more morphologically abnormal spermatozoa in the semen, but it did not cause significant loss in BW, motility of the spermatozoa, composition of the seminal plasma or testosterone concentration--its effect needs further examination.

Testicular function and semen characteristics of Awassi rams treated with melatonin out of the breeding season.

The objective of this study was to evaluate the effect of long-term melatonin treatment applied during the non-breeding season on semen characteristics, endocrine function of testicles and baseline level of insulin-like growth factor-I (IGF-I) in Awassi rams kept in the temperate continental zone of Europe and used as semen donors in an artificial insemination (AI) programme. On 23 February (day 0), slow-release melatonin implants were inserted subcutaneously into rams (n = 8). Control animals (n = 8) received no treatment. In both groups, basic semen parameters (concentration, total motility, fast and slow forward motility, morphology), GnRH-induced testosterone response and basal IGF-I concentration were evaluated on days 0, 47 and 71. No differences were found in concentration of spermatozoa, total motility, and numbers of spermatozoa with fast and slow progressive motility and normal/abnormal morphology between the melatonin-treated and the control group. However, in melatonin-treated animals, basal and GnRH-induced testosterone levels were slightly elevated on day 47 and became significantly higher on day 71 (P < 0.05) as compared to controls. There was no difference in plasma IGF-I levels between the groups. In conclusion, slow-release melatonin applied during the non-breeding season improves testicular testosterone production but does not influence the semen characteristics and the IGF-I level of semen donor Awassi rams used in an AI programme and kept in the temperate continental zone of Europe.

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.

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.