Fertility In Sheep Research Articles

“influence of biostimulators on the fertility of caracul sheep”

“influence of biostimulators on the fertility of caracul sheep”

Удосконалення та впровадження сучасних біотехнологічних методів відтворення овець в Інституті біології тварин НААН

The article presents the scientific achievements of researchers of the Institute of Animal Biology NAAS in reproductive biotechnology in sheep breeding. The Ukrainian-Polish experiment on improving the in vitro method of sheep fertilization, which ended with the birth of the first lamb in Ukraine, is covered in detail. The scientific achievements of the staff of the institute were the basis for the introduction of an improved method of laparoscopic insemination of sheep in Ukrainian farms. Laparoscopic insemination of local breeds of sheep of Lviv, Zakarpattia, Kherson and Dnipropetrovsk regions with sperm of sheep of specialized fat breeds was carried out and fertilization of more than 80% was obtained. Also, scientific and practical work was carried out to improve and implement methods of stimulating superovulation in ewes of the Texel breed, non-surgical washing of embryos and their transplantation to bright recipients of the Ukrainian Carpathian breed.

Study on the correlation between BMPR1B protein in sheep blood and reproductive performance.

Sheep reproductive performance is one of the important economic traits in sheep farming. The bone morphogenetic protein receptor 1B (BMPR1B) gene and protein may play an important role in sheep fertility. This study was to investigate the association of blood BMPR1B protein expression with reproductive performance in sheep. Mongolian sheep with single and twin births and polytocous Small Tail Han sheep were selected due to differences in birth numbers. The BMPR1B mRNA in sheep blood was measured by a reverse transcription-polymerase chain reaction as well as the BMPR1B protein was measured by enzyme-linked immunosorbent assay in blood samples of Mongolian and Small Tail Han sheep. The results demonstrated that blood BMPR1B concentration in Mongolian sheep with twin birth was higher (P < 0.05) than Small Tail Han sheep and Mongolian sheep with single birth. The protein concentration in the anestrus season was higher (P < 0.045) than those in the estrus season for both Mongolian and Small Tail Han sheep. Moreover, BMPR1B concentration in Mongolian sheep increased (P < 0.05) at the age of 6 to 12 mo and that in Small Tail Han sheep increased (P < 0.05) at the age of 3 to 6 mo. The result indicates that the increase in BMPR1B protein concentrations in the blood of Mongolian ewes and Small Tail Han ewes may be beneficial to follicular development, but too high or too low of this blood protein concentration in Mongolian and Small Tail Han sheep is not conducive to ovulation.

Effect of Point Mutation in the Growth Differentiation Factor 9 Gene of Oocytes on the Sterility and Fertility of Awassi Sheep.

Growth differentiation factor 9 (GDF9) plays a critical role in ovarian follicular development and ovulation rate. The present study aimed to investigate the correlation between the single-nucleotide polymorphism (SNP) of the GDF9 gene and reproductive performance variables, such as fertility and sterility in Awassi sheep. Forty pairs of ovaries from a total of 40 slaughtered Iraqi Awassi ewes were used in this study. Twenty of the ovaries were collected from sterile ewes and the other 20 ovaries were taken from fertile ewes for genomic DNA extraction, polymerase chain reaction, and sequencing to detect GDF9 gene polymorphism. Follicles and oocytes of all the 40 ovaries were evaluated and compared with the results of genotyping. Furthermore, histopathological and microscopic evaluations were performed for 40 ovarian tissues of the two groups. The sequence analysis revealed that exon I had three SNPs, including T(114)C, G(129)R, and G(199)A. The first two SNPs were silent mutations and the last mutation was missense responsible for the substitution of glutamic acid with lysine at position 67. The current study showed a significant increase (P&amp;le;0.01) in GG, AA, CC, GA, and GG genotypes at G(129)R, G(199)A, T(114)C, G(129)R, and G(199)A loci, respectively. Moreover, the TT genotype in locus T(114)C was recorded to significantly augment (P&amp;le;0.05) in the fertile ewes. Mutant GA genotype of the G(129)R locus led to a significant (P&amp;le;0.05) increase in the percentage of follicles (4-8 mm) and oocytes number, compared to wild GG. On the other hand, a significant decrease was recorded in the mutant AA genotype in G(199)A, compared to wild GG. Differences between CC and TT genotypes at T(114)C locus were not significant. Histopathological examination revealed hypoplasia in the ovarian tissue of sterile ewes accompanied by fibrous connective tissue invasion and follicles degeneration. However, in the fertile ewes, the ovarian tissues were normal with the presence of numerous corpus albicans and degenerative corpus luteum. According to the findings of this study, the homozygote mutation in fertile ewes minimized the number of follicles and oocytes leading to sterility, while the heterozygote mutation was reported in the fertile Awassi ewes.

Cumulus cells during in vitro fertilization and oocyte vitrification in sheep: Remove, maintain or add?

The objective was to evaluate the developmental competence of immature and matured ovine oocytes after removing, maintaining or adding cumulus cells (CC) associated to vitrification by Cryotop method. Three experiments were performed involving 3,144 oocytes. In Experiment 1, CC were removed from immature, matured or fertilized oocytes subjected to in vitro embryo production. In Experiment 2, oocytes were vitrified either in MI or MII stage with or without CC, while a control group with CC remained unvitrified. In Experiment 3, oocytes partially denuded from CC were vitrified either in MI or MII stage, and a co-culture of fresh CC was added or not soon after warming to complete in vitro maturation (IVM) and in vitro fertilization (IVF), or IVF, respectively, while a control group remained unvitrified. In Experiment 1, the cleavage rate, development rate on Day 6 and blastocyst rate on Day 8 were improved when CC were maintained until the end of IVF (P < 0.05). In Experiment 2, vitrification of oocytes with enclosed CC showed a tendency to increase cleavage (P = 0.06) and improved blastocyst rate (P < 0.05). In Experiment 3, adding CC as co-culture after vitrification-warming tended to improve cleavage rate (P = 0.06) and increased hatching rate (P < 0.05). Regarding oocyte stage, vitrification of in vitro matured oocytes resulted in greater developmental competence than immature stages (P < 0.05). In conclusion, CC seems to have a relevant role for in vitro embryo development in either fresh or vitrified oocytes.

Effect of Dietary Omega-3 Poli Unsaturated Fatty Acids During the Flushing Period on Reproductive Performance of Karayaka Ewes

This experiment was conducted to investigate the effects of supplemented omega 3 poly unsaturated fatty acids on fertility of Karayaka sheep during the flushing period. This trial was arranged on 3-4 year old, average 55±0.5 kg live weight, 80 head Karayaka sheep were distributed completely Randomize into 4 groups. Oestrus synchronization was performed in the three groups of sheep except for control group. Experimental groups were pasture, pasture (oestrus synchronization), barley and Omega-3. Progeny yields were determined as 80 % in the control, 125 % in the pasture, 116 % in the barley and 135% in the omega-3 groups.The highest twin birth was observed in omega 3 group (44%), follwed by pasture group (33%) and barley group (24%). The results indicated that, addition of omega-3 polyunsaturated fatty acids to supplemental feeds increased fertility of Karayaka sheep.

Niğde İlinde Yetiştirilen Akkaraman Irkı Koyunların Bazı Döl Verim Özellikleri ve Kuzuların Büyüme Performansı

Bu çalışmada, yarı ekstansif koşullarda yetiştirilen Akkaraman koyunlarının bazı döl verim özellikleri ile kuzuların büyüme performansları araştırılmıştır. Araştırmanın hayvan materyalini, Niğde merkez ilçesine bağlı 34 işletmede bulunan 300 baş koç, 6000 baş Akkaraman koyunu ile onların kuzuları oluşturmuştur. Araştırma 2012-2016 yılları arasında 5 yıl sürdürülmüş ve çalışma süresince 30162 baş kuzu doğum ağırlığı, 29517 baş kuzunun 90. gün canlı ağırlığı ve 30000 baş Akkaraman koyununun bazı döl verim parametreleri saptanmıştır. Akkaraman koyunlarında doğum oranı ortalama %90,1, ikiz doğum oranı %20,8, bir doğuma düşen kuzu sayısı 1,12 olarak saptanmıştır. Akkaraman ırkı kuzuların doğum ağırlığının ortalaması 4,23 kg ve 90. gün canlı ağırlık ortalaması da 23,05 kg olarak belirlenmiştir. Kuzuların doğum ağırlıkları ve 90. gün canlı ağırlıkları üzerine yıl, doğum tipi ve cinsiyetin etkisi önemli bulunmuştur. Sonuç olarak, halk elinde yarı ekstansif koşullarda yetiştirilen Akkaraman ırkı koyunların döl verimi ve kuzuların büyüme özelliklerinin iyileştirilebileceği ve bunun gibi ıslah projelerinin uygulanması ile koyunculuk işletmelerin ekonomik durumlarının iyileştirilebileceği kanaatine varılmıştır.

Clinical and laboratory prognostic indicators for fertility in sheep

With the use of technology of artificial insemination in sheep farms are not yet defined criteria for assessing the full value of the preparation of females for insemination, and hence – the possibility of prediction and correction of their fertilization, which prevents the rational use of cryopreserved semen and ensuring the maximum reception of the offspring. We have proved the prognostic importance of fertilization of the morphofunctional state of the vulva and the vagina and the quality of mucus in sheep breeds during estrus. The material of the study was 327 sheep of ascanian breeding, which during the sexual intercourse before insemination examined the vulva, vagina and evaluated the estrus slime (number, color, consistency, presence of impurities, elasticity, electrical resistance, type of crystallization, protein content). The results of ultrasound diagnosis of pregnancy were determined by the fertility of sheep with different integral compositions of clinical and laboratory parameters. It has been established that in sheep, in which fertility in the first sexual cycle reached 65.1%, most often found a pink, moderately edematous vulva with clear mucus. In females with pale mucous membrane and insignificant amount of mucus, the effectiveness of inseminates declined to 53.3-58.0%. In a significant amount of estral mucus, the proportion of infertile animals increased twofold. At the same time, the selection of liquid, but cloudy, or thick mucus is a sign of an unfavorable prognosis, in which fertility decreases by 1.8-2.1 times (p &lt;0.001). Dense, white, paste-like isolates were observed in a small number of sheep, mostly bright at the beginning of the anestral season. Low fertility in the first sexual hunting (35.5%) and a high multiplicity of repeated inseminations (29.0%) indicate that sheep with thick estral slime are only beginning to enter the sexual season, and this quality of secrecy indicates an inadequate estrogenization of the body. It was also found that in the infertile sheep during sexual hunting, the protein content of cervical mucus was 4.8 times higher, and the elasticity of mucus was reduced by 2.9 times. The most prevalent was the prognosis of average fertilization (53.3-58.0%), which was recorded in 62.9% of experimental sheep. The prognosis of high fertilization, which resulted in 62.5-65.1% of oseminins, was found in 27.8% of females. At the same time, the number of females with a fertility forecast at 40% was only 3.1%, and the prevalence of an unfavorable prognosis, in which fertility was the smallest (30.0-35.5%), reached 6.2%. Key words: sheep, askanian breeding, estrus, fertility prognosis, estral mucus, vulva, vagina, artificial insemination.

Fertility in male sheep: modulators of the acute effects of nutrition on the reproductive axis of male sheep

Animals adjust the time of year that they reproduce through their ability to perceive and respond to critical aspects of their environment, such as photoperiod, nutrition or the socio–sexual milieu, and their genotype determines the degree of response to each stimulus. Ultimately, information from environmental cues filters through to the GnRH neurones in the brain which are the primary regulator of fertility. Each of these cues has been studied in isolation and the mechanisms by which they affect GnRH secretion are now better, if not fully, understood. In the field, the brain centres that control GnRH must integrate information from all cues at any given time before 'formulating a reproductive decision'. In this review, the effect of this integration is illustrated by showing how the acute GnRH response to a nutritional signal can be modulated by genotype, photoperiod and social cues, to the point of being completely blocked under some circumstances. Candidate pathways that may mediate these modulatory effects at both the whole body and brain have been proposed, although none of these pathways are confirmed and some have not yet been studied. As a guide for further research, we propose a working model that integrates the inputs and explains the interactions between them.

Gestational nutrition 1: alterations to gestational nutrition can increase indicators of fertility in sheep.

The aim of this study was to examine the relationships between gestational nutrition, fetal ovarian development and offspring fertility in female sheep and to highlight the potential mechanisms underlying these relationships. Adult sheep (n = 79) were fed either a maintenance or 0.6 of maintenance plane of nutrition for the first 55 days of gestation and thereafter fed ad libitum. Fetuses were collected for analysis at days 55 and 75 of gestation. Female offspring were monitored from birth until 19 months of age. Effects of restricted nutrition were observed on maternal plasma concentrations of progesterone, creatinine, albumin and Ca2+ at day 55 and creatinine at day 75. Concentrations of metabolic factors and steroid hormones in day 75 fetal plasma were not affected by the restricted maternal plane of nutrition. At day 55 of gestation, fetal ovarian germ cell development was not affected by maternal plane of nutrition. At day 75 of gestation ovaries from fetuses whose dams were exposed to restricted nutrition contained more germ cells but had lower germ cell proliferation rates than controls. For female offspring at 8 months of age, the dams gestational plane of nutrition did not affect the onset of puberty, ovulation rate (OR) and antral follicle counts (AFC). At 19 months of age, ewes from dams exposed to the restricted plane of gestational nutrition had higher OR, AFC and progesterone concentrations while concentrations of FSH were lower. In conclusion, while effects on fertility per se are yet to be determined, a reduced maternal plane of gestational nutrition can improve indicators of fertility in female offspring.

Influence of Progesterone-Treatment Length and eCG Administration on Appearance of Estrus Behavior, Ovulatory Success and Fertility in Sheep.

Simple SummaryThis study examines the pre-ovulatory and ovulatory events (in terms of the timing of the onset of estrous and subsequent ovulation) and the yields obtained (in terms of ovulation rate, progesterone secretion, and fertility) after insertion of Controlled Internal Drug Release (CIDR) for five, six, seven, or fourteen days, with or without equine chorionic gonadotrophin (eCG).The present study characterizes, for sheep, the occurrence and timing of the onset of estrus behavior and ovulation and the yields obtained (ovulation rate, progesterone secretion, and fertility) after Controlled Internal Drug Release (CIDR) insertion for five, six, seven, or fourteen days, with or without equine chorionic gonadotrophin (eCG) in ewes of the Segureña meat breed. All the treatments showed above 80% of females displaying estrus, but the onset of estrus was earlier and more synchronized when using eCG and, among groups with eCG, onset of estrus was earlier in the sheep treated for 14 days than in the short-term treatments (p < 0.05 for all). Administration of eCG after either short- or long-term treatments assured the occurrence of fertile ovulations in all the animals. Conversely, ovulatory success without eCG was found to be dependent on treatment length, with a high percentage of animals ovulating after five days of treatment (83.3%) and very low percentages after treatment for six or seven days (40% and 20%, respectively). Ovulation rate and progesterone secretion were similar among animals ovulating, but ovulation failures predetermined the fertility yields obtained in response to the treatments. Hence, the best results were found after treatment for 14 days plus eCG, and for 5 days without eCG (83.3 for both, p < 0.05 when compared to the other groups with different treatment lengths and with or without eCG).

The application of in vitro fertilization techniques for the evaluation of ram fertility

The prediction of field fertility of a given ram by using in vitro tests would be of great importance for the reproductive management in sheep flocks. There are many in vitro procedures available for evaluating semen quality and fertilizing ability, and the method chosen depends on the objective of evaluating the sperm and the available resources. The in vitro evaluation of semen fertilizing ability was firstly developed for the artificial insemination (AI) purposes and secondly for the application of in vitro fertilization (IVF) technique. The IVF techniques allow the assessment of fertility in terms of ability to penetrate and fertilize in vitro mature oocytes and ultimately to yield component embryos following IVF and culture. In this review are briefly presented in vitro studies performed in an attempt to establish an accurate laboratory test for the evaluation and, even more, the prediction of field fertility in sheep.

New objective measurements of semen wave motion are associated with fertility in sheep.

In sheep, wave motion in semen is currently used by AI centres to select ejaculates for insemination. Despite its low cost, convenience and established ability to predict fertility, the subjectivity of this assessment is a limiting factor for its applicability. The aims of the present study were to establish an objective method for the analysis of wave motion and to assess the associations of objective parameters with fertility after cervical insemination. Collective sperm motion in undiluted semen was observed by phase contrast microscopy at low magnification in a 100-µm deep glass chamber. Images of moving dark waves over a grey background were recorded and analysed by the optic flow method, producing several velocity-related parameters. Turbulence was assessed from the motion of fluorescent polystyrene beads. Among objective parameters, optical flow entropy and the average speed of beads were both able to discriminate ejaculates suitable for insemination. Two synthetic variables of optic flow and bead motion and a global objective variable were computed from linear combinations of individual parameters and compared with the subjective motion score for their predictive value. These were as efficient as the wave motion score for assessing fertility and can be proposed for the assessment of ram semen in routine AI procedures.

The effect of service ram on reproductive performances and birth weight of lambs

The investigation was conducted in population of Mis breed of sheep, divided into three groups. For reproduction had use rams of Ile de France breed. Induction and synchronization of oestrus was done off-season in October. The percentage of lambing sheep, sheep fertility, and number of lambs acquired per father, sex and birth type of lambs were observed. Ram 1 had a highest number of ewes lambed with an excellent percentage of mating success and highest fertility rate of ewes with differences on fertility rate of 17% (between group of ewes in ram 1 and ram 2), 36% (group of ewes in ram 1 and ram 3) and 19% (group of ewes in ram 2 and ram 3).The highest birth weight were on lambs born single from ram 3, born twins from ram1, triplets of ram 3. For the lambs born quadruplets (unfortunately only in rams 1 and 2 with one lamb of each was alive) the lamb of ram 2 was higher in birth weight. The male and female lambs of ram 3 got the highest birth weight while the female lambs of ram 1 acquired the lowest birth weight. The highest average birth weight of lambs was born single, male; born triplets? male from lambs of ram 3 having an average birth weight of 6.36kg and 4.0 kg but got the lowest for lambs born twins on female lambs 3.66 kg. The male lambs of ram 1 got the highest average birth weight on lambs born twins with an average birth weight of 4.38 kg but the lowest on triplets born 3.3kg. Unfortunately only one each of the two ram with lambs born quadruplets alive both male and the higher was that lamb of ram 2 with a birth weight of 3.3 kg. Result showed the influence of ram on number of lambs born and lambs? birth weight. Between subject effects Father* birth type showed a significant effect on birth weight of lambs.

Climate zone influences the effect of temperature on the day of artificial insemination on fertility in two Iberian sheep breeds

To determine whether climate, based on the Koppen Climate Classification, influences the effect of temperature on the day of artificial insemination (AI) on fertility in sheep, 1,931 AI performed on Spanish farms of the Rasa Aragonesa (RA) and Churra (CH) breeds were studied. Farms were categorized as Koppen BSk (Farm BSk-RA; n=229), and Koppen Cfb (Cfb-RA; n=372), Koppen Csb (Csb-CH; n=908), and Koppen Cfb (Cfb-CH; n=422). Mean, maximum, and minimum temperatures (°C) were recorded, and thermal amplitude (maximum-minimum temperatures) calculated. Each set of temperature data was distributed between percentile-groups (≤50% and >50%), below or above the median. Temperatures at AI were significantly (P 50 percentile groups indicated that inseminations performed when temperatures were within the >50 percentile had a significantly (P 1 for one or more of the meteorological variables under study; meanwhile, in the other two climates, OR were 0.05). In conclusion, the effects of temperature on fertility after AI differed depending on the climate zone in which the flocks were reared. The results have implications for the scheduling of insemination dates to achieve the maximal performances.

Histological analysis and identification of spermatogenesis-related genes in 2-, 6-, and 12-month-old sheep testes.

Testis development and spermatogenesis are vital factors that influence male animal fertility. In order to identify spermatogenesis-related genes and further provide a theory basis for finding biomarkers related to male sheep fertility, 2-, 6-, and 12-month-old Small Tail Han Sheep testes were selected to investigate the dynamic changes of sheep testis development. Hematoxylin-eosin routine staining and RNA-Seq technique were used to perform histological and transcriptome analysis for these testes. The results showed that 630, 102, and 322 differentially expressed genes (DEGs) were identified in 2- vs 6-month-old, 6- vs 12-month-old, and 2- vs 12-month-old testes, respectively. GO and KEGG analysis showed the following: DEGs in 2- vs 6-month-old testes were mainly related to the GO terms of sexual maturation and the pathways of multiple metabolism and biosynthesis; in 6- vs 12-month-old testes, most of the GO terms that DEGs involved in were related to metabolism and translation processes; the most significantly enriched pathway is the ribosome pathway. The union of DEGs in 2- vs 6-month-old, 6- vs 12-month-old, and 2- vs 12-month-old testes was categorized into eight profiles by series cluster. Subsequently, the eight profiles were classified into four model profiles and four co-expression networks were constructed based on the DEGs in these model profiles. Finally, 29 key regulatory genes related to spermatogenesis were identified in the four co-expression networks. The expression of 13 DEGs (CA3, APOH, MYOC, CATSPER4, SYT6, SERPINA10, DAZL, ADIPOR2, RAB13, CEP41, SPAG4, ODF1, and FRG1) was validated by RT-PCR.

Physical evaluation, morphological and identification of seminal proteins in Santa Ines sheep

SUMMARY This study aimed to identify proteins in the seminal plasma associated with fertility in sheep of Santa Inês in Manaus, AM, using twodimensional electrophoresis techniques associated with mass spectrometry. Semen samples from eight adult sheep were collected by removing an aliquot for the physical and morphological assessments of semen and seminal plasma was subjected to SDS-PAGE profile and two-dimensional electrophoresis. Gels were stained with colloidal Coomassie, scanned and analyzed using ImageMaster 2D Platinum software, version 6.0. The selected individual spots were cut from the master gel, digested with trypsin and subjected to identification by mass spectrometry (MALDITof / Tof). Of the 108 spots detected in the gel, it selected 10 differential spots (based on the distribution thereof in the bidimensional gel and pre-analysis of the 2D ImageMaster Platinum Software) identifying 03 proteins: clusterin, a protein 14-3-3 zeta chain and Ram Seminal versicles 22kDa Protein. The identity of these proteins implies that the components of seminal plasma participate in physiological processes involved in sperm protection, motility and sperm capacitation, all associated with fertility. These proteins need to be better studied to see whether the same could be used as molecular markers of fertility as they were also found in other studies conducted with sheep Santa Ines.

Identification of g.170G>A and g.332G>A mutations in exon 3 of leptin gene (Bcnl and Cail) and their association with semen quality and testicular dimensions in Sanjabi rams

The purpose of this study was to investigate leptin gene polymorphisms and their relationships with the characteristics of sperm quality and testicular dimensions. Semen samples were collected from 96 Sanjabi rams during autumn and spring seasons over two years. Simultaneously, the dimensions of length, width and scrotal circumference were measured. Blood samples were taken from the jugular vein to extract DNA. PCR was performed to amplify a 463bp fragment including exon 3 of leptin gene. PCR products were digested by Bcnl and Cail restriction enzymes to identify 170G>A and 332G>A mutations in exon 3, respectively. Leptin gene polymorphism in 170G>A locus had an effect on individual motility trait, water test and scrotal circumference (P<0.05) and animals with the AA genotype had the highest individual motility compared with the GG and GA genotypes (P<0.05). The AG genotypes had the highest water test compared with the GG and AA genotypes (P<0.05) but GG genotype had higher scrotal circumference than that of GA and AA genotypes (P<0.05). The results showed that polymorphism in 332G>A locus had a significant effect on viability trait, water test and scrotal circumference as GA genotypes had the highest amounts for these traits compared with GG genotypes (P<0.05). Based on our knowledge, the current study is the first report on the association of leptin gene polymorphisms with sperm fertility and testicular dimensions in sheep, which suggests leptin gene as a potential gene to be used in breeding programs in order to improve fertility in herds.

Feed supplementation improves estrus response and increases fertility of sheep induced to breed out of season.

To test the efficacy on reproductive performance of nutritional supplementation in an out-of-season mating system, 66 adult prolific Barbarine ewes were selected and induced to breed using "ram effect". The ewes were allocated to two homogeneous groups; each ewe received on a daily basis 700g of hay and 500g of barley grains starting 3weeks before or 1week after rams' introduction in group 1 and group 2, respectively. Supplementation ended 1month after rams' introduction and mating lasted 60days. Final live weight 30days after introduction of rams was higher (P < 0.05) for ewes in group1 (39.45 vs. 36.72kg). Seven days after introduction of rams, ewes in group 1 recorded higher plasma glucose levels than females in group 2 (4.12 and 3.9S.E.M. 0.05mmoll-1). Proportions of ewes which displayed estrus between days 16 and 26 were 48 and 38% in group 1 and group 2, respectively (P < 0.05), and those which had a normal induced cycle (16-17days) were 25 and 11% in group 1 and group 2, respectively (P < 0.05). Fertilities were higher (P < 0.05) for ewes in group 1 than in group 2 (91.17 vs. 75.75% and 97.1 vs. 81.8% for fertility at induced estrus and total fertility, respectively). It is concluded that a timed supplementation starting 3weeks before introduction of rams is effective in yielding high reproductive performance for the prolific strain of the Barbarine breed.

Relationship between the genetic hemoglobin polymorphism, morphometry and fertility of Pramenka sheep breed from Central Bosnia

The characteristics of these sheep are highlighted depth measures of external appearance with modest width measures. Another weaker feature of Pramenka sheep is poor fertility. Despite the mentioned disadvantages, Pramenka sheep is the most grown sheep in Central Bosnia and sheep production is based on it. Methodical selection to improve the characteristics of Pramenka sheep has not applied. However, sheep breeders tend to improve the qualitative and quantitative characteristics of sheep, and that means more intensive work on the selection. In this sense, genetic markers are used to carry out the selection lately. Three types of hemoglobin, HbAA, Hband HbBB of Pramenka sheep population (at 189 male and female animals) in Central Bosnia were segregated by the method of electrophoresis. The following genotype frequencies are determined: HbAA 0.11; Hb0.41; and HbBB 0.48. Allele frequencies, HbA and HbB for Pramenka sheep breed (estimate based on genotype frequencies) were 0.315 and 0.685. It was found that the population of sheep was in the equilibrium of the frequency of hemoglobin genotypes. Sheep with HbAA genotype had lower morphometric measures in relation to the other two genotypes. The statistically significant difference between sheep with Hbgenotype and HbAA genotype was recorded only for the shin perimeter. The ewes that lambed one lamb have the following frequency of HbAA, Hband HbBB genotypes: 0.13; 0.40 and 0.47, and the ewes with twins: 0.02; 0.40 and 0.58. Fertility, as important quantitative characteristic of sheep, was more emphasized in genotype HbBB, than in HbAA genotype. This was confirmed by the statistical analysis.