Seasonal Effects on the Performance of Finishing Pigs' Carcass and Meat Quality in Indoor Environments.

Most retailers in EU countries pay pig breeders for their animals' lean meat percentage, which does not align fully with measures of pork quality (such as colour). In this study, we investigated the effects of season (summer vs. autumn) on finishing pigs' performance, carcass characteristics, and meat quality parameters in 24 slaughter pigs. Growing performance traits (live weights, average daily weight gain), slaughter values (warm and cold carcass weights, trunk length, fat thickness) and meat quality parameters (pH at 45 min and 24 h postmortem, colour, drip loss, thawing loss, cooking loss, shear force, and meat composition) were recorded. Seasonal differences were more pronounced for the initial age, the number of days in the growing-finishing phase, and the average daily gain. There was also a significant difference in the trunk length between groups, the fat thickness on withers and loin, and also in mean fat thickness. A significant difference was found in the case of pH, total drip loss, and meat colour (L*). The intramuscular fat and collagen content of meat was significantly higher in summer; in contrast, the protein content of meat samples was considerably lower in summer. In conclusion, seasonal effects on finishers' performance, lean meat values, and several meat quality parameters highlight the importance of more profound seasonal settings of climate control to fulfil the progressively changing quantitative and qualitative requests of pork sector participants from farm to fork.

Changes in Chemical Composition and Fatty Acid Profile of Milk and Cheese and Sensory Profile of Milk via Supplementation of Goats' Diet with Marine Algae.

The aim of the present study was to assess the effects of the low level of Schizochytrium limacinum marine algae (daily 5 g per animal) on the milk, cheese, and whey composition; fatty acid profile of milk and cheese; and the sensory profile of goat milk using an e-nose device. Thirty Alpine goats were randomly divided into two groups: the control group (C, n = 15)-fed grass with daily 600 g concentrate and the experimental group (MA, n = 15) who received the same forage and concentrate supplemented with 5 g/head/day marine algae. Animals were kept indoors and the investigation period lasted 52 days, including the first six weeks as the period of adaptation and the last 10 days as the treatment period. During the adaptation period, bulk milk samples from each group were collected once a week (0, 7, 14, 21, 28, 35, and 42 d), while during the treatment period (10 days), bulk milk samples from each group were taken every day, and cheese samples were processed from bulk milk each day from both groups. Marine algae supplementation had no negative effect on milk composition. In contrast, the marine algae inclusion significantly elevated the fat and protein content of whey and the protein content of cheese, as well as the recovery of fat and protein in the curd, while increasing the cheeses' moisture content on a fat-free basis. The marine algae supplementation significantly increased the docosahexaenoic acid (DHA) and the rumenic acid (CLA c9t11) concentrations and decreased the n-6/n-3 ratio in the milk and cheese. There were no significant differences between the C and the MA group with regard to the sensory profiles of the milk. It can be concluded that the milk obtained from goats given daily supplementation of 5g of MA has a fatty acid profile more beneficial to human health, without any negative effects on the milk's aromatic components.

Position of Hungarian Merino among other Merinos, within-breed genetic similarity network and markers associated with daily weight gain.

OBJECTIVE: In this study, we aimed to position the Hungarian Merino among other Merino-derived sheep breeds, explore the characteristics of our sampled animals' genetic similarity network within the breed, and highlight single nucleotide polymorphisms (SNPs) associated with daily weight-gain. METHODS: Hungarian Merino (n = 138) was genotyped on Ovine SNP50 Bead Chip (Illumina, San Diego, CA, USA) and positioned among 30 Merino and Merino-derived breeds (n = 555). Population characteristics were obtained via PLINK, SVS, Admixture, and Treemix software, within-breed network was analysed with python networkx 2.3 library. Daily weight gain of Hungarian Merino was standardised to 60 days and was collected from the database of the Association of Hungarian Sheep and Goat Breeders. For the identification of loci associated with daily weight gain, a multi-locus mixed-model was used. RESULTS: Supporting the breed's written history, the closest breeds to Hungarian Merino were Estremadura and Rambouillet (pairwise FST values are 0.035 and 0.036, respectively). Among Hungarian Merino, a highly centralised connectedness has been revealed by network analysis of pairwise values of identity-by-state, where the animal in the central node had a betweenness centrality value equal to 0.936. Probing of daily weight gain against the SNP data of Hungarian Merinos revealed five associated loci. Two of them, OAR8_17854216.1 and s42441.1 on chromosome 8 and 9 (-log10P>22, false discovery rate<5.5e-20) and one locus on chromosome 20, s28948.1 (-log10P = 13.46, false discovery rate = 4.1e-11), were close to the markers reported in other breeds concerning daily weight gain, six-month weight, and post-weaning gain. CONCLUSION: The position of Hungarian Merino among other Merino breeds has been determined. We have described the similarity network of the individuals to be applied in breeding practices and highlighted several markers useful for elevating the daily weight gain of Hungarian Merino.

Andrological and cytogenetic investigations of an infertile Przewalski's stallion.

The case of an 8-year-old, sexually active but infertile Przewalski's stallion (Equus ferus przewalskii) was studied. Besides the infertility, the stallion also showed permanent problems with its body condition, being obviously weaker than all the other group members. The horse was kept in a separate place for two years with 12 mares in its harem group (six mares had foals earlier); however, none of the mares covered got pregnant. Andrological and cytogenetic investigations revealed underdeveloped testes, arrested spermatogenesis, azoospermia, and XY/XXY/X0 mosaicism. We classify the case as a mosaic Klinefelter syndrome, the first reported case in Przewalski's horse.

Effect of Marine Algae Supplementation on Somatic Cell Count, Prevalence of Udder Pathogens, and Fatty Acid Profile of Dairy Goats' Milk.

The aim of this study was to evaluate the effect of the Schizochytrium limacinum marine algae on the milk composition and fatty acid profile, somatic cell count, and prevalence of pathogen bacteria in the raw milk of multiparous Alpine goats. Twenty-eight dairy goats were randomly allocated to two groups: control group (C)-fed with 1500 g alfalfa hay and 600 g concentrate; experimental group (MA)-received the same forages and concentrate supplemented with 10 g/head/day marine algae. The goats were housed indoors, while the experiment lasted five weeks, and the milk samples were taken every week. Marine algae feeding had no negative effect on milk composition. The marine algae inclusion significantly decreased the milk somatic cell count and the presence of udder pathogens in the MA group. Mean somatic cell count and presence of udder pathogens were 5.73 log cells/mL and 31%, respectively, in the C group, while these values were 5.34 log cells/mL and 10%, respectively, in the MA group. The marine algae supplementation significantly increased DHA and rumenic acid concentration in the milk of the MA group (0.32 and 0.99 g/100 g of fatty acids, respectively) compared to the C group (0.04 and 0.65 g/100 g of fatty acids, respectively). It can be concluded that a diet supplemented with marine algae significantly improves the udder health of goats and the concentrations of health-promoting fatty acids in milk.

Detection of pregnancy in sheep using an ELISA for pregnancy-specific protein B.

The early detection of pregnancy and the determination of fetal numbers have economic benefits in sheep production because of the seasonal breeding patterns where missing a breeding opportunity means the loss of one productive year. The purpose of this study was to evaluate the efficacy of the B6-HRP ELISA for ovine pregnancy-specific protein B (oPSPB) measurement in the detection of pregnancy and estimation of fetal numbers in different sheep breeds. BioPRYN® ELISA assay kit was used for the detection of pregnancy in the experimental animals. Ninety-three ewes of three breeds (British Milksheep - BM, Lacaune - L and Transylvanian Racka - TR), each from three farms in Hungary, were included in the study. BM and L ewes were artificially inseminated (AI). Thirty-five days after AI, all ewes were examined by transabdominal ultrasound. The TR flock was mated naturally over a six-week period. At the end of the mating period, the ewes were similarly examined by ultrasound. Blood samples were taken from all pregnant ewes twice (35 and 65 days after AI), and serum samples were assayed by the BioPRYN test. It can be concluded that the detection of serum PSPB by ELISA is a much easier, safer, less expensive and highly accurate method for the detection of ovine pregnancy. Although some breed-related differences were detectable at 35 and 65 days post breeding, no differences in oPSPB levels were found in pregnant ewes carrying different numbers of fetuses.

X- and Y-chromosome-specific variants of the amelogenin gene allow non-invasive sex diagnosis for the detection of pseudohermaphrodite goats.

The Polled Intersex Syndrome (PIS) is responsible for the absence of horns in homozygous and heterozygous goats causing a female-to-male sex reversal in the homozygous polled genotypic female (XX) goats. A simple and efficient non-invasive method was elaborated to detect the genotypic sex from hair and faecal samples using a pair of primers to amplify the X- and Y-linked alleles of the amelogenin gene. The PCR products were easily distinguishable using agarose gel electrophoresis: we detected an X-specific single band in samples originating from healthy phenotypic females and double (X- and Y-) bands in samples from males. The new PCR method is applicable for diagnosing the sex of PIS-affected animals already as newborn kids, in contrast with the phenotypic findings appearing only after puberty, and thus it may replace the cumbersome chromosome investigations.

Lutein, Trolox, ascorbic acid and combination of Trolox with ascorbic acid can improve boar semen quality during cryopreservation.

BACKGROUND: Due to pour quality of cryopreserved boar semen, artificial innsemination with frozen-thawed semen is quite limited. Developing protocols of boar semen cryopreservation represents a priority but also a challange. OBJECTIVE: The goal of the present study was to evaluate the antioxidant potential of lutein, Trolox, ascorbic acid, and certain combinations of Trolox with ascorbic acid on boar semen cryopreservation procedure. MATERIALS AND TMETHODS: Antioxidants were added to lactose-egg yolk extender, containing a final concentration of 3% glycerol and 0.5% Equex-STM. Semen of six boars was cryopreserved using straw-freezing procedure. After cryopreservation semen was thawed and evaluated for motility, normal apical ridge (NAR), hypo-osmotic swelling test (HOST) and DNA fragmentation index (DFI). Data were analyzed by one-way ANOVA. RESULTS: The results showed better motility after thawing at the concentration of 10 µM lutein, 200 µM Trolox, 200 µM ascorbic acid and 400-200 µM Trolox and ascorbic acid. The supplementation on boar freezing extender with 10 µM lutein increased post-thawed motility, NAR and HOST values (P < 0.01), and decrease DFI (P < 0.05) in comparison with control group. Similar results were obtained using 400-200 µM Trolox and ascorbic acid, with better results in the case of DFI (P < 0.01). In comparison with the control group, a concentration of 200 µM Trolox and 200 µM ascorbic acid provided significant differences (P < 0.01) of motility and NAR. CONCLUSION: The analysis of sperm characteristics showed that lutein and the mix between Trolox and ascorbic acid used in boar semen cryopreservation can improve the quality of spermatozoa.

Is the function of the porcine sperm reservoir restricted to the ovulatory period?

The uterotubal junction (UTJ) and caudal isthmus are recognized as a functional pre-ovulatory sperm reservoir (SR). Spermatozoa are released from the SR in a complex and concerted action. However, whether this functionality is restricted only to the ovulatory period is still open to debate. Our study was aimed to analyze the presence of spermatozoa within the UTJ (SR), isthmus (ISTH) and ampulla (AMP) after laparoscopic intrauterine insemination (LIUI) either in the peri- (PERI) or post-ovulatory (POST) period or at mid cycle (MID). Each uterine horn of estrus synchronized gilts (n=12) was inseminated with 20 ml sperm (29.5×10(6) cells/ml). Oviducts were recovered 7 h after LIUI and separated into the UTJ, ISTH and AMP, and sections were flushed with 10 ml PBS+EDTA solution. After centrifugation, the sperm pellet was evaluated by Cerovský staining. The median sperm numbers in the PERI, POST and MID groups were 578, 171 and 789 in the UTJ; 545, 233 and 713 in the ISTH; and 496, 280 and 926 in the AMP, respectively, and there were differences between the POST and MID groups (P<0.05) but not between the oviductal sections of each group (P>0.05). Compared with the MID group, the percent of intact sperm cells was higher (P<0.01) in the PERI and POST groups (32.8 vs. 66.4 and 76.8%). Also, the percentages of aberrations in the acrosome and tail were higher (P<0.05) in the MID group. Based on this, it can be assumed that the sperm reservoir is active during different phases of the estrus cycle. However, the mid-cycle oviduct environment considerably impairs sperm cell quality.

Saving genetic resources of native pigs in Occidental and Oriental countries - practical examples of the characterization and utilization of native pigs in Hungary and Laos.

Worldwide, only a few "fatty" pig breeds exist with different and/or regional utilization. Using the Hungarian Mangalica, which almost went extinct in Europe and the Lao Moo Lat pig, which still has a large population in South-East Asia as exemples, we wanted to demonstrate that indigenous (fatty) pig breeds may represent both national value and tremendous economic potential. Since these less prolific and less productive breeds cannot contribute to mass production, new market roles and methods should be established for them in the premium segment of pork trading. Thus their preservation and propagation needs the comprehensive collaboration of commercial, governmental actors and researchers. Briefly summarizing the history, we report the current results of reproductive physiology research. The commercial renaissance of Mangalica pigs is indebted to the enthusiastic efforts of basic scientists, pig breeding experts and dedicated Mangalica producers. Scientific achievements were applied to practical breeding and production of delicious pork and processed products, which ultimately made the economic success in the Mangalica sector possible. Both, research on and utilization of endangered (pig) breeds maintain not only breed diversities, but also may improve the livelihood of farmers worldwide.

Comparison of cytoskeletal integrity, fertilization and developmental competence of oocytes vitrified before or after in vitro maturation in a porcine model.

Aim of the study was to investigate the effect of vitrification on viability, cytoskeletal integrity and in vitro developmental competence after in vitro fertilization (IVF) of oocytes vitrified before or after in vitro maturation (IVM) using a pig model. Oocytes from abattoir-derived porcine ovaries were vitrified at either the germinal vesicle (GV) or metaphase II (MII) stage by modified solid surface vitrification (SSV). Oocyte viability was evaluated by stereomicroscopic observation whereas their nuclear stage and morphology of microtubules and F-actin were observed by confocal microscopy after immunostaining. Fertilization was assessed by orcein staining. The survival rate after vitrification was higher for MII-stage than for GV-stage oocytes. However, the ability of surviving oocytes to reach the MII stage after vitrification at the GV stage (GV-vitrified oocytes) was similar to that of control oocytes. Furthermore, after IVM, GV-vitrified oocytes had better spindle and F-actin integrity than oocytes vitrified at the MII stage (MII-vitrified oocytes). In accordance with this result, GV-vitrified oocytes had better ability to extrude the second polar body and support male pronucleus formation after in vitro fertilization (IVF), in comparison to MII-vitrified oocytes. Fertilization rates did not differ among groups. Finally, the ability of GV-vitrified oocytes to develop into embryos was superior to that of MII-vitrified oocytes. However, both vitrified groups showed reduced blastocyst development compared with the control group. In conclusion vitrification of porcine oocytes at the GV stage is advantageous in conferring better cytoskeletal organization and competence to develop to the blastocyst stage in comparison with vitrification at the MII stage.

Comparison of ethylene glycol and propylene glycol for the vitrification of immature porcine oocytes.

Our aim was to optimize a cryoprotectant treatment for vitrification of immature porcine cumulus-oocyte complexes (COCs). Immature COCs were vitrified either in 35% ethylene glycol (EG), 35% propylene glycol (PG) or a combination of 17.5% EG and 17.5% PG. After warming, the COCs were in vitro matured (IVM), and surviving oocytes were in vitro fertilized (IVF) and cultured. The mean survival rate of vitrified oocytes in 35% PG (73.9%) was higher (P<0.05) than that in 35% EG (27.8%). Oocyte maturation rates did not differ among vitrified and non-vitrified control groups. Blastocyst formation in the vitrified EG group (10.8%) was higher (P<0.05) than that in the vitrified PG group (2.0%) but was lower than that in the control group (25.0%). Treatment of oocytes with 35% of each cryoprotectant without vitrification revealed a higher toxicity of PG on subsequent blastocyst development compared with EG. The combination of EG and PG resulted in 42.6% survival after vitrification. The maturation and fertilization rates of the surviving oocytes were similar in the vitrified, control and toxicity control (TC; treated with EG+PG combination without cooling) groups. Blastocyst development in the vitrified group was lower (P<0.05) than that in the control and TC groups, which in turn had similar development rates (10.7%, 18.1% and 23.3%, respectively). In conclusion, 35% PG enabled a higher oocyte survival rate after vitrification compared with 35% EG. However, PG was greatly toxic to oocytes. The combination of 17.5% EG and 17.5% PG yielded reasonable survival rates without toxic effects on embryo development.

Reproductive function of Hungarian Mangalica boars: effect of seasons.

Seasonal changes in testis volume, testosterone (T) productivity (GnRH test) and semen characteristics of Mangalica boars were studied. The biggest testis volume was measured in autumn and the smallest in winter. Significant differences were demonstrated between autumn-winter (P = 0.012) and autumn-spring (P = 0.015) in testis volume. The highest basic T concentration (Tb) was observed in autumn and the lowest in summer. The provoked T concentration (Tincr) was significantly higher in autumn than in spring (P = 0.0007). A strong correlation was observed between T concentrations and testis volume in spring. The highest ejaculate volume was measured in winter while the lowest in autumn. Significant differences were found in semen concentration as well as in the total number of spermatozoa per ejaculate between seasons. The highest number of abnormal sperm cells was observed in spring while the lowest in summer. It can be concluded that the ejaculate of the Mangalica breed tends to be of lower volume and higher sperm concentration as compared to most pig breeds. Seasonal differences could be observed in testicular measurements, testosterone production capacity and sperm morphological features; however, sperm motility remained constantly high during the study.

Meiotic progression, mitochondrial features and fertilisation characteristics of porcine oocytes with different G6PDH activities.

The aim of the present study was to investigate the developmental competence, mitochondrial characteristics and chromatin status of immature follicular porcine oocytes selected for their glucose-6-phosphate dehydrogenase (G6PDH) activity by brilliant cresyl blue (BCB) staining. In Experiment 1, the oocyte parameters were determined in parallel right after BCB staining (T(0)), after 22 h of in vitro maturation (IVM) (T(22)) and after 44 h of IVM (T(44)) (n = 496). BCB-stained oocytes (BCB+) at T(0) were characterised by fibrillated chromatin filaments in their germinal vesicles (GV) and diakinesis stages whereas unstained (BCB-) oocytes at T(0) contained in their GV mainly condensed stages of chromatin (P < 0.05). After 22 h of IVM BCB+ oocytes showed a prominent chromatin configuration of metaphase I and after 44 h the majority developed a M II nuclear configuration in contrast to the BCB- group (P < 0.0001). Differences were also observed between the two oocyte populations in their mitochondrial activity (P < 0.05). At the beginning of IVM BCB+ oocytes were characterised by high mitochondrial activity in their cytoplasm. The BCB+ oocytes showed clear visible homogenous distributions of mitochondria (P < 0.005) and contained more aggregated clusters of mitochondria in contrast to BCB- oocytes (P < 0.005). In Experiment 2, 318 oocytes were tested for their G6PDH activity and introduced to IVM and IVF. Only oocytes from the BCB+ group, which were matured after 44 h up to the stage of M II (81.6%) were fertilised (17.4%), penetrated (46%) or activated (15.6%) after IVF. These results indicate a relationship between the G6PDH activity of porcine oocytes before IVM and their subsequent nuclear development, mitochondrial activity and aggregation.

Comparison of luteinizing hormone, leptin and progesterone levels in the systemic circulation (Vena jugularis) and near the ovarian circulation (Vena cava caudalis) during the oestrous cycle in Mangalica and Landrace gilts.

The objective of this study was to evaluate luteinizing hormone (LH) and luteal progesterone (P4) secretion in systemic blood and blood near the ovaries in Mangalica (M) and Landrace (L) gilts by implanting catheters into the Vena jugularis and the Vena cava caudalis via the Vena saphena, respectively. Furthermore, leptin was analyzed in jugular vein blood. Blood was collected twice daily from day 7 to day 19 of the oestrous cycle and frequently (10-min intervals for 6 h) on day 9, day 12 and day 15 in M (n=3) and L gilts (n=4). L gilts had congruent pulsatile LH secretion in both veins, but the LH concentrations in M were always below the assay sensitivity during the luteal phase. In both breeds, episodic P4 secretion was found in the jugular and caval veins, and both sampling site and breed had an influence on P4 secretion (P<0.05). The mean concentration of P4 was higher (P<0.01) in utero-ovarian blood (75.8+/-5.3 in M; 49.6+/-4.2 ng/ml in L) than in the periphery (31.3+/-2.0 in M; 21.2+/-1.8 ng/ml in L). M pigs had a lower number of corpora lutea (9.7+/-2.3 vs. 20.5+/-4.4), and analysis of the P4 secretion ratio per corpus luteum revealed an influence of breed (P<0.01). This ratio was significantly higher in M (3.8+/-0.3 and 8.7+/-0.7 ng/ml) compared with the L gilts (1.4+/-0.1 and 2.8+/-0.3 ng/ml) in the jugular and caval veins, respectively. Blood sampling from the Vena cava caudalis is potentially more precise than from the Vena jugularis for evaluation of ovarian P4 secretion. Both the higher P4 concentration and increased leptin secretion (11.3+/-0.6 vs. 3.0+/-0.1 ng/ml, P<0.05) and consequently the altered LH secretion pattern in the Mangalica may contribute to the lower fecundity of this breed.

Comparison of follicular and oocyte development and reproductive hormone secretion during the ovulatory period in Hungarian native breed, Mangalica, and Landrace gilts.

Only a very small amount of physiological data is available about the low fertility (mean litter size is 5.7+/-0.8) of Hungarian native breed, Mangalica (M), sows. The aim of the present paper is to reveal the differences in preovulatory follicle development and intrafollicular oocyte maturation between M and Landrace (L) gilts, with special reference to the peri- and postovulatory secretion and peripheral concentrations of estradiol-17beta (E2), progesterone (P4), and luteinizing hormone (LH). The number of preovulatory follicles was 6.8+/-1.4 and 19.6+/-6.6 in M and L gilts, respectively. A lower degree of cumulus expansion and a lower percentage of mature oocytes (TI/M II) was noted in M. Higher LH and E2 peak levels, a longer E2 to LH peak interval, and lower embryo survival was confirmed. Interestingly, despite the lower number of corpora lutea, a higher peripheral blood level of P4 was shown in M than in L gilts. Both diminished follicular development and protracted oocyte maturation may be involved in low fecundity in M, and the present findings may explain these reproductive phenomena.

Ovarian activity and oocyte development during follicular development in pigs at different reproductive phases estimated by the repeated endoscopic method.

The aim of the present study was to assess follicular and oocyte development in the same gilts during three phases of their reproductive life [prepuberal gilts (PP; 6.0 months of age), puberal gilts (P; 9.5 months of age) and primiparous sows (S)]. Follicular development was stimulated by the injection of 1,000 IU of equine chorionic gonadotropin (eCG) followed by 500 IU of human chorionic gonadotropin (hCG) 72 h later. Cumulus-oocyte-complexes (COCs) were recovered by endoscopic ovum pick up/aspiration from preovulatory follicles of the left ovary, and the follicular fluid (FF) from the right ovary was collected 34 h after the hCG treatment by endoscopy. Altogether, 19 pigs were used in the PP and P trials and 12 in the S trial. From the left ovaries, 168, 190 and 82 follicles were aspirated and 106, 125 and 42 COCs, respectively, were recovered (recovery rate 61 +/- 27, 63 +/- 21 and 53 +/- 22%, respectively). The mean number of follicles was greater in the P phase than in the PP phase (19.7 +/- 6.8 vs. 15.7 +/- 6.8; p=0.06) and S phases (14.2 +/- 4.0; p<0.05). More uniform oocytes with an expanded cumulus were aspirated in the P and PP phases than in the S phase (90 and 78 vs. 46%; p<0.05). Furthermore, the meiotic configuration in oocytes (T I/M II stage) differed between the three phases (56 and 62 vs. 0%; p<0.05). Progesterone (P4) levels in FF decreased from 590.0 +/- 333.6 (PP) to 249.1 +/- 72.6 (P) and 161.4 +/- 75.2 ng/ml (S) (p<0.05). Estradiol-17beta (E2) levels differed between PP and P gilts and S sows (9.3 +/- 2.9, 21.9 +/- 10.6 and 94.0 +/- 15.9 pg/ml, respectively; p<0.05), and the P4/E2 ratio was 72, 15 and 5, respectively. These results indicate differences in follicular and oocyte development between the reproductive phases investigated. Puberal gilts should preferably be used in IVF and breeding programs. The lower reproductive potential of primiparous sows must be taken into consideration in breeding. Any prediction of lifetime performance based on individual ovarian reactions of prepuberal gilts is unreliable.

Comparison of luteinizing hormone and steroid hormone secretion during the peri- and post-ovulatory periods in Mangalica and Landrace gilts.

The objective of this study was to determine plasma concentrations of luteinizing hormone (LH), progesterone (P4) and estradiol-17beta (E2) in Mangalica gilts (M), a Hungarian native breed, and compare them with Landrace gilts (L) during the peri- and post-ovulatory periods. The estrous cycle of gilts was synchronised by Regumate feeding, and ovulation was induced with a gonadotropin-releasing hormone (GnRH) agonist. Blood sampling was carried out via indwelling jugular catheters three times a day and in 2-h intervals during a 16-h period after the GnRH application. The concentrations of LH, E2 and P4 were determined by immunoassays. Gilts of both breeds showed a typical gonadotropin and gonadal hormone secretion pattern. Preovulatory E2 peaks were observed on day 2 (M) and day 4 (L) after the last Regumate feeding. Highest E2 concentration was different between M and L breeds (46.5 +/- 5.7 vs. 26.0 +/- 6.8 pg/ml, P < 0.05). Maximum LH levels measured up to 6 h after GnRH were not different between M and L breeds (11.5 +/- 4.1 vs. 6.6 +/- 2.3 ng/ml). Both LH amounts during surge (41.1 +/- 15.9 vs. 27.5 +/- 6.1 ng/ml) and total over LH release (73.4 +/- 22.2 vs. 50.0 +/- 8.7 ng/ml) did not differ significantly between M and L breeds. P4 concentrations started to rise on day 6 after Regumate feeding and increased significantly from 0.6 +/- 0.3 and 0.7 +/- 0.4 ng/ml to maximal 14.0 +/- 2.4 and 11.3 +/- 2.1 ng/ml in M and L breeds, respectively. Mean P4 secretion was higher in M on days 10-15 (12.9 +/- 2.6 vs. 9.3 +/- 2.2 ng/ml; P<0.05). At the same time the number of corpora lutea was lower in M compared to L (10.3 +/-1.5 vs. 17.8 +/- 5.0, P<0.05). In our experiment, there was no evidence that differences in the secretion of analysed hormones during the peri- and post-ovulatory periods are a possible cause of usually lower fecundity in Mangalica gilts.