Egyes metabolikus és hormonális jellemzők alakulása ellés után és hatása az első ovuláció időpontjára valamint az asszisztált reprodukciós technológiák eredményességére anyajuhokban = The changes of certain metabolic and endocrine characteristics postpartum and its effect to the day of first ovulation and the efficiency of assisted reproductive technologies in ewes

A vizsgálatok keretében a szezonnak, fotóperiódusnak és a metabolikus állapotnak az ellés után jelentkező első ivarzás/ovuláció idejére gyakorolt hatását vizsgáltuk intenzíven tejelő, nem szoptató Awassi juhokban. Az eredmények azt jelzik, hogy körülményeink között (kontinentális zóna) az Awassi juhok petefészkének aktivitása szezonálissá válik és az ellés utáni első ivarzás/ovuláció az ősszel ellett, nem szoptató anyákban nagyon korán megtörténhet, még azelőtt, hogy a méh teljes involuciója befejeződhetne. A plazma metabolitok és metabolikus hormonok szintje a vizsgált időszakban mindvégig a fiziológiás tartományban maradt; az intenzív tejtermelés sem borította fel a metabolikus egyensúlyt. A fénykiegészítés késleltetheti az ellés után jelentkező első ivarzás/ovuláció jelentkezésének idejét. A tenyész szezonon kívül alkalmazott melatonin kezelésnek a spermiumokra, a here endokrin funkciójára és az IGF-I szintre kifejtett hatását is vizsgáltuk Awassi tenyész kosokban. A vizsgálatok eredményei azt jelzik, hogy a melatonin javíthatja a here tesztoszteron termelését, de nincs hatással a spermiumtermelésre és az IGF-I szintre. | The influence of the season, photoperiod and metabolic status on the time of the first postpartum ovulation in lactating, non-suckled dairy Awassi ewes was studied. Trials were conducted in a commercial Awassi flock, where lambs are weaned immediately after birth. It was found that ovarian function of Awassi population became seasonal under temperate continental weather and the first postpartum ovulation of non-suckling, autumn-lambing dams may happen very early, even before the completion of uterine involution. Plasma metabolites and metabolic hormones were in physiological range in the periparturian period; the metabolic balance was not turned by the intensive milk production. Additional lightening may retard the time of first postpartum ovulation. The effect of melatonin treatment applied out of the breeding season on semen characteristics, endocrine function of testicles and baseline level of IGF-I in Awassi rams were also studied. It was found that melatonin treatment may improve testicular testosterone production but does not influence semen parameters and IGF-I level

Effect of feeding different oils on plasma corticosterone in broiler chickens

A study was conducted to examine the effects of different oils on the plasma corticosterone concentrations of broiler chickens fed ad libitum or deprived of feed for 24 hours. A total of 36 Ross broilers were randomly assigned to one of three dietary treatments at 10 days of age and fed a grower diet supplemented with 60 g/kg soybean oil (rich in linoleic acid, C18:2n–6), linseed oil (rich in a-linolenic acid, C18:3n–3) or fish oil (rich in C14:0, C16:0, C16:1n–7, C20:1n–9; eicosapentaenoic acid and docosahexaenoic acid, EPA, C20:5n–3 and DHA, C22:6n–3), respectively, for 18 days. Dietary supplementation of fish oil resulted in lower (P < 0.05) baseline plasma corticosterone levels of chickens fed ad libitum for 18 days compared to soybean and linseed oil supplementations. Feed deprivation for 24 h induced a significant (P < 0.05) increase in corticosterone concentration in every treatment group compared to the ad libitum-fed birds. The hormone levels of feed-deprived birds did not differ significantly among groups fed diets supplemented with different oils

A növekedési hormon genotípus (AluI polimorfizmus) hatása egyes metabolikus és hormonális jellemzők ellés utáni alakulására, valamint az első ovuláció időpontjára holstein fríz tehenekben = The influence of STH genotype (AluI polymorphism) on certain metabolic and endocrine characteristics, and the day of first ovulation in postpartum Holstein Friesin cows

Az STH genotípusnak (AluI-polimorfizmus) az ellés után fellépő energiahiányos állapot dekompenzálódásával (ketózis) és a szaporodási mutatók alakulásával mutatott összefüggéseit vizsgálták tejhasznosítású (holstein fríz) tehenekben, illetve üszőkben. Megállapításaik: (1) Az egyes genotípusok eloszlása: LL kb. 80-85 %, LV kb. 10-15 %, VV legfeljebb 2-3 %. (2) Nem volt kimutatható jelentősebb közvetlen befolyása az ellés előtti napokban biztosított különböző energiaszintű takarmányozásra adott metabolikus és endokrin válaszra, a hasnyál-mirigy inzulin termelésére, a plazma NEFA, BHB, inzulin és IGF-I ellés utáni plazma-koncentrációjára, továbbá a tejtermelés nagyságára. (3) Nagyszámú állaton vizsgálva kimutatható az STH polimorfizmus összefüggése az elléstől az első ovulációig eltelő időtartam hosszával, és/vagy az ellés utáni első 30 napon bekövetkező kondíciópont-csökkenés mértékével. (4) Munkánk során ? a V hordozók alacsony számaránya miatt ? szándékaink ellenére nem sikerült ugyan megnyugtató számú adat birtokába jutnunk, valószínű azonban, hogy az STH genotípusnak nincs közvetlen hatás a luteinizációnak a posztovulációs P4-szintemelkedés ütemében megnyilvánuló intenzitására sem. Az STH polimorfizmus és az állat metbolikus, továbbá szaporodási jellemzőinek tisztázásához azonban még további vizsgálatok szükségesek. | The interrelations of STH (Alu-I) genotype with decompensation of postpartum negative energy balance (hyperketonaemia, ketolactia kenonuria) as well as with reproduction were studied in dairy cows (Exp. 1-4) and heifers (Exp. 5). The main observations: (1) The incidence of various genotypes in the studied herds: LL: about 80-85 %, LV: about 10-15 %, VV: max. 2-3 %. (2) The STH genotype did not have direct influence on the endocrine and metabolic response on different levels of energy supply in the pre-calving period, the pancreatic insulin production, the plasma levels of NEFA, BHB, insulin and IGF-I in the postpartum period, furthermore on the milk production. (3) Hen it was studied in large number of animals, there were interrelations between the STH genotype, the degree of body condition loss and the duration of postpartum acyclicity / time of the first postpartum ovulation. (4) Although in this trial ? due to the low rate of valin carriers (LV+VV genotypes) ? we could not get clear improvement, but it is almost sure that the STH genotype do not have any direct effects on the luteinisation, represented by the post-ovulatory rise of plasma progesterone levels. However, also further studies are required for the clarification of physiological details in interrelationships of STH genotypes, metabolism and reproduction

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

Pannon White (n512) male rabbits (weight: 4050 to 4500 g, age: 9 months) received 2ml 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 (n512) 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 (n510) 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 gonadotropinreleasing 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

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

Systemic (intramuscular, IM) 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) IM treatment (single IM group) resulted in a similarly low bacteriological recovery rate (14%) as seen in the untreated controls (18%). IM treatment (30,000 IU/kg) on 4 consecutive days (4 IM group) resulted in significantly higher quarter-based recovery rates than that in the single IM group. The bacteriological recovery rates obtained in the intracisternal and 4 IM 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

Heart rate, heart rate variability, faecal glucocorticoid metabolites and avoidance response of dairy cows before and after changeover to an automatic milking system

The heart rate variability (HRV) parameters of dairy cows were monitored during parlour (PARL) and the later installed automatic (AMS) milking on a small-scale commercial dairy farm in Hungary. The aim of the study was to assess stress in relation to the type of milking and the frequency of human interaction. Parlour milking involved regular moving and crowding of the animals with frequent human interaction, which were much less frequent in automatic milking. The first phase of the study was conducted prior to the changeover [n = 27] and the second two months afterwards [n = 19 (of the cows from the first phase)]. Heart rate (HR) was recorded by the Polar RS800 CX recording system. HRV parameters indicative of sympathovagal balance were calculated for periods of lying and standing in the barn, waiting before milking and milking, respectively. Morning and evening faecal glucocorticoid concentrations were also measured. Fear of humans was tested by an avoidance distance test. Baseline HRV parameters showed no difference (P > 0.05) between the two systems. In the periods before, during and after milking a higher sympathetic tone was detected in cows in the PARL phase. Mean faecal glucocorticoid concentrations were higher at the time of parlour milking. The avoidance distance did not differ between the two phases. The results suggest that automatic milking might be less stressful for cows than parlour milking, possibly due to the shorter duration of restraint after milking and the less frequent human interaction

Peripheral circulating insulin-like growth factor-I and -II in cattle

Interrelationships between circulating concentrations of the insulin-like growth factors (IGF-I and IGF-II) were investigated in 235 blood samples taken from 145 healthy beef or dairy calves, bulls and cows of different breeds and ages. Autoradiography of Western ligand blots indicated different IGF binding protein (IGFBP) profiles between sera from different categories of cattle. Each IGF radioimmunoassay was validated by determining the effects of IGFBPs, ligand and contraligand, as well as serial dilution and comparison with results obtained after molecular sieve chromatography in acid. In female cattle mean values for IGF-I varied from 5.1 nmol/l in postparturient Holstein cows to 18.5–20.5 nmol/l in growing beef heifers, while mean IGF-II concentrations ranged from 30.0 nmol/l in the cows to 14.7–15.7 nmol/l in the beef heifer calves. In male cattle mean serum IGF-I ranged widely from 8.2 nmol/l in 1-day-old Holstein calves to 67.4 nmol/l in 16-month-old Simmental-type bulls. Mean IGF-II concentrations decreased from 22.9 nmol/l in 1-day-old Holstein bull calves to 11.9 nmol/l in 12-month-old beef bulls. Thus, total molar IGF concentrations were fairly stable in female cattle (24.7–35.1 nmol/l) but extended from 27.3 nmol/l to 81.8 nmol/l in the male cattle. The tendency for a reciprocal relationship between serum concentrations of these growth factors was most obvious in the periparturient cows