Affecting Ovulation Rate Research Articles

Alfalfa Spring Black Stem and Leaf Spot Disease Caused by Phoma medicaginis: Epidemic Occurrence and Impacts.

Alfalfa spring black stem and leaf spot disease (ASBS) is a cosmopolitan soil-borne and seed-borne disease caused by Phoma medicaginis, which adversely affects the yield, and nutritive value and can stimulate production of phyto-oestrogenic compounds at levels that may adversely affect ovulation rates in animals. This review summarizes the host range, damage, and symptoms of this disease, and general features of the infection cycle, epidemic occurrence, and disease management. ASBS has been reported from over 40 countries, and often causes severe yield loss. Under greenhouse conditions, reported yield loss was 31-82% for roots, 32-80% for leaves, 21% for stems and 26-28% for seedlings. In field conditions, the forage yield loss is up to 56%, indicating that a single-cut yield of 5302 kg/ha would be reduced to 2347 kg/ha. P. medicaginis can infect up to 50 species of plants, including the genera Medicago, Trifolium, Melilotus, and Vicia. ASBS is more severe during warm spring conditions before the first harvest than in hot summer and cooler winter conditions, and can infect alfalfa roots, stems, leaves, flowers, pods, and seeds, with leaf spot and/or black stem being the most typical symptoms. The primary infection is caused by the overwintering spores and mycelia in the soil, and on seeds and the cortex of dead and dry stems. The use of resistant cultivars is the most economical and effective strategy for the control of ASBS. Although biological control has been studied in the glasshouse and is promising, chemical control is the main control method in agriculture.

The role of inositol in improving fertility in patients with PCOS

Introduction and purpose
 Polycystic ovary syndrome is a common reproductive disorder, accompanied primarily by hyperandrogenism and insulin resistance. Myo-inositol (MI) and D-chiro-inositol (DCI), have emerged as potential therapeutic agents due to their role as insulin sensitizers. This article examines the effects of inositol therapy on fertility in women with PCOS and its role in assisted reproductive technology (ART). Studies suggest that inositols alleviate irregular menstruation, reduce androgen levels and positively affect ovulation rates. MI supplementation has also shown positive effects during controlled ovarian hyperstimulation and IVF procedures, reducing the required FSH dose and cycle length. However, despite positive results on ovulation and menstrual regularity, the article indicates the need for further studies to establish inositol as standard ART therapy in patients with PCOS.
 Material and methods
 The following review was based on articles from the PubMed and Google Scholar databases. Key search terms included polycystic ovary syndrome; assisted reproductive treatment, insulin resistance, inositols, Myo-inositol, D-chiro-inositol.
 Conclusions 
 Inositols are a promising therapeutic option for women with PCOS. They have been shown to have positive effects on improving insulin sensitivity and fertility. However, despite inositol's safety and easy availability, the ideal dose and timing of use, the appropriate MI/DCI ratio, as well as the potential side effects of excess DCI and the problem of inositol resistance, require further comprehensive studies.

Progress on the effect of FecB mutation on BMPR1B activity and BMP/SMAD pathway in sheep.

BMPR1B is the first major gene of litter size identified in sheep. However, the molecular mechanism of the FecB mutation that increases the ovulation rate in sheep is still unclear. In recent years, it has been demonstrated that BMPR1B activity is regulated by the small molecule repressor protein FKBP1A, which acts as a key activity switch of the BMPR1B in the BMP/SMAD pathway. The FecB mutation is located close to the binding site of FKBP1A and BMPR1B. In this review, we summarize the structure of BMPR1B and FKBP1A proteins, and clarify the spatial interactive domains of the two proteins with respect to the location of the FecB mutation. Then the relationship between the FecB mutation and the degree of affinity of the two proteins are predicted. Finally, the hypothesis that FecB mutation causes change of activity in BMP/SMAD pathway by affecting the intensity of the interactions between BMPR1B and FKBP1A is proposed. This hypothesis provides a new clue to investigate the molecular mechanism of FecB mutation affecting ovulation rate and litter size in sheep.

К ВОПРОСУ ГЕНЕТИЧЕСКОГО УЛУЧШЕНИЯ ПЛОДОВИТОСТИ ОВЕЦ

Most sheep breeds are low-prolific, which, along with other reasons, leads to low profitability of the industry. In intensive systems of industrial sheep breeding, high prolificacy of sheep can increase the efficiency of sheep production. Cross-breeding of low-prolific breeds with highrolific breeds has been the main means of genetic improvement of prolificacy, while intra-breed selection has been considered relatively ineffective due to low heritability of the trait. Mutations that reliably affect ovulation rate and hence lamb numbers have been found in several breeds around the world in genes designated as “major genes”. Most of these mutations are mapped in genes related to the TGFβ superfamily. Genotyping for these major genes permits the use of a markerssisted selection method for crossbreeding to introduce useful mutations into new breeds. Mitochondrial DNA analysis, whole genome association studies (GWAS), whole genome sequencing, transcriptome analysis and proteomic studies of high- and low-prolific sheep have identified additional genetic variations with moderate or minor effects on prolificacy. Using information on polymorphisms in these “medium genes” and “minor genes” may facilitate selection work for higher prolificacy within a particular production system. Although high prolificacy is associated with a risk of pregnancy toxicosis, increased embryonic mortality, reduced lamb survival in early postnatal ontogeny, and a high risk of shortening the productive longevity of sheep, the prospect is to identify a set of genes with moderate effects on prolificacy.

Interactions between Nutrition and the "Ram Effect" in the Control of Ovarian Function in the Merino Ewe.

Simple SummaryClean, green, and ethical management of sheep flocks involves the use of socio-sexual stimuli (the “ram effect”) to coordinate nutritional inputs into reproductive success. However, the value of the “ram effect” is limited by three factors: (i) the proportion of the ewe flock that ovulates; (ii) ovulation rate in ewes that respond to the ram stimulus; and (iii) luteal failure after the first ram-induced ovulation, leading to short luteal phases. We tested whether these problems could be overcome by using a brief nutritional supplement (500 g lupin grain per head daily for 6 days) to stimulate ovarian activity. Lupin supplementation before ram introduction did not improve the percentage of the ewe flock that ovulates or reduce the frequency of short cycles (so will not improve the synchrony of lambing). However, lupin supplementation after ram introduction should be used to increase prolificacy.We tested whether short-term nutritional supplementation (500 g lupin grain per head daily) would affect the response of ewes to the ram effect. Experiment 1 (end of non-breeding season): ewes were supplemented for either Days −6 to −1 relative to ram introduction (n = 24) or for 12 days after ram introduction (Days 11 to 22 of the ram-induced cycle; n = 29). Controls (n = 30) were not supplemented. Across all groups, 94–100% of ewes ovulated. Supplementation before ram introduction did not affect ovulation rate at the ram-induced ovulation but increased it during the ram-induced cycle (Control 1.37; supplemented 1.66; p < 0.05). Experiment 2 (the middle of non-breeding season): the supplement was fed for Days −5 to −1 relative to ram introduction. Again, supplementation did not increase number ovulating (Control 16/29; Supplemented 10/29) but it did increase ovulation rate at the ram-induced ovulation (Control 1.31; Supplemented 1.68; p < 0.05). In neither experiment did supplementation affect the frequency of short cycles. Supplementation before ram introduction did not improve the percentage of ewes ovulating or reduce the frequency of short cycles (so will not improve the synchrony of lambing). However, supplementation after ram introduction can increase prolificacy.

Impact of gonadotropin-releasing hormone administration at the time of artificial insemination on conception risk and its association with estrous expression

Cows with reduced estrous expression have compromised fertility. The aim of this study was to determine whether the administration of GnRH at the time of artificial insemination (AI) would affect ovulation rates and the fertility of animals expressing estrous behavior of lesser intensity. Cows were enrolled at the time of estrus from 3 farms (n = 2,607 estrus events; farm A: 1,507, farm B: 429, farm C: 671) and randomly assigned to receive GnRH at AI or not (control). The intensity of estrous expression, monitored through leg-mounted activity monitors, was determined using the maximum activity during estrus; estrous expression was categorized as greater or lower relative to the farm median. On farm A, cows were assessed at alert, and 24 h, 48 h, and 7 d post-alert for ovulation using ultrasonography. Pregnancy per AI was confirmed at 35 ± 7 d post-estrus for cows that were inseminated. Differences between treatments were tested using the GLIMMIX procedure of SAS. Treatment with GnRH at the time of AI increased pregnancy per AI (41.3 ± 1.6 vs. 35.7 ± 1.7%). An interaction between treatment and estrous expression on pregnancy per AI was found. Control cows with greater estrous expression had greater pregnancy per AI than those with lesser expression, whereas GnRH administration increased pregnancy per AI for cows with lesser estrous expression but not those with greater expression (GnRH, greater intensity: 43.5 ± 2.1; GnRH, lesser intensity: 37.8 ± 2.2; control, greater intensity: 42.6 ± 2.2; control, lesser intensity: 31.0 ± 2.2%). A higher proportion of cows with greater estrous expression that were administered GnRH at AI were found to ovulate by 48 h and 7 d post-estrus; however, ovulation of cows with lesser estrous expression was unaffected by GnRH administration. In conclusion, fertility of cows with reduced estrous expression may be increased using GnRH at the time of AI; however, increased ovulation rates do not seem to be the direct mechanism behind this relationship.

A novel route of follicle-stimulating hormone administration with a split-single ischiorectal fossa in Thai-Holstein crossbred superovulation programs under heat stress conditions.

The objectives of this study were to compare the efficiency of a split single injection of follicle-stimulating hormone (FSH) given by either intramuscular (split-single IM) or ischiorectal fossa (split-single IRF) injection to the traditional treatment and to determine the concentrations of FSH. The temperature and humidity index (THI) values were interpreted together with the ovarian responses and embryo characteristics. The ovarian responses in the split-single IRF group were similar to those of the control group (p > .05) but higher compared with the split-single IM group (p < .05). Higher peak levels of plasma FSH in the split-single IRF group did not differ compared with the control group (p > .05) but were lower in split-single IM administration (p < .05). The results showed a significant decrease in the numbers of large follicles and corpora lutea (CLs) in the moderate THI compared with low and high THI (p < .05). The high THI affected ovulation rate as well as the numbers of transferable embryos and degenerated embryos (p < .05). In conclusion, the split-single IRF administration had a comparable superovulatory response to the traditional twice-daily protocol. Moreover, the ovulation rate, ovarian follicle responses, and embryo quality were affected by heat stress.

Ovulation and ovulation rate in ewes under grazing conditions: factors affecting the response to short-term supplementation

The relationships between ovulation rate and nutrition remain confused, probably because of uncontrolled variation in experimental conditions. To help resolve the problem, we analyzed data from 20 experiments conducted between 2002 and 2016, in Uruguay with grazing ewes. All experiments were carried out by a single laboratory under comparable conditions of experimental design and measured variables. The studies used a total of 3 720 ewes, of purebred Corriedale, Polwarth, or East Friesian x Polwarth genotypes. In all experiments, a control group grazed native pastures and extra nutrition was provided to the treatment groups using either improved pastures or supplements. Ovulation rate was measured by counting corpora lutea using laparoscopy or rectal ultrasound or by counting foetuses at ultrasound on day 45 of gestation. For statistical analysis, data were grouped according to nutritional treatment (control or supplemented) and, within these groups, type of supplement to provide energy or protein (protected or not from rumen degradation). Across all experiments, 92–99% of the ewes ovulated and the effects of diet, length of supplementation, and initial live weight and genotype are reported. Within diets, ovulation was most affected by overall energy intake during supplementation (P < 0.01). Ewes that grazed native pastures supplemented with protein supplements had higher ovulation rates (P < 0.05) than control ewes grazing only native pastures. The addition of tannins to the protein supplement, to protect it from degradation in the rumen, did not further increase the ovulation rate. In unsupplemented ewes that had access to legume pastures, ovulation rates did not increase when the legume pasture was rich in tannins although only ewes that grazed tanniniferous legumes had marginally higher ovulation rates than the control ewes (P < 0.05). When ewes grazing native pastures were supplemented with energy, their ovulation rate did not increase above those of nonsupplemented ewes. Live weight at the start of supplementation also affected ovulation rate. We conclude that ovulation was most affected by overall energy intake, whereas the factors that affected ovulation rate during short-tern nutritional supplementation were intake of protein from highly digested supplements or dietary protein protected from ruminal degradation.

Early uterine development in pigs

The capacity of pig uterine tissues to recognize and respond to maternal and conceptus signals determines whether pregnancy can be established and defines the environment in which embryonic and fetal growth occur. Limits of uterine capacity may be defined genetically. However, the extent to which functional uterine capacity approaches genetic potential may be determined, in part, by the success of organizational events associated with growth, morphogenesis and cytodifferentiation of uterine tissues. It is important, therefore, that these events be identified and evaluated with respect to their potential effect on adult uterine function. Histogenesis of the pig uterus begins prenatally, but is completed postnatally. Transformation of the uterine wall from histoarchitectural infancy to maturity occurs between birth and day 120. Morphogenetic events characteristic of the first 60 days of neonatal life proceed normally in gilts ovariectomized at birth. These events include appearance and proliferation of uterine glands, development of endometrial folds, and growth of the myometrium. Endometrial development during this period involves alterations in patterns of epithelial and stromal DNA synthesis, coordinated changes in the distribution and biosynthesis of extracellular matrix glycosaminoglycans and cell surface glycoconjugates, and specific alterations in patterns of uterine protein secretion. The ovary-independent, spatially coordinated nature of these events suggests that neonatal uterine development is regulated locally via dynamic cell-cell and cell-extracellular matrix interactions. The extent to which such potentially critical interactions must be preserved to ensure developmental success remains unknown. However, the normal pattern of ovary-independent cellular and molecular events associated with development of the uterine wall was disrupted by treating neonatal gilts with oestradiol valerate, and daily administration of oestrogen to gilts from birth to day 13 did not affect ovulation rate, but did reduce embryonic survival by 22% on day 45 of gestation in adults that were exposed to oestrogen neonatally. These observations support the idea that some organizational events associated with development of the neonatal uterine wall must be allowed to proceed without interruption to ensure that adult uterine function is not compromised. Efforts to identify specific developmental determinants of uterine capacity may be facilitated by examining the consequences of xenobiotically induced interruption of uterine development on adult uterine function. Such studies may also contribute to identification of uterine factors affecting embryonic survival and fetal growth.

MON-042 The Effect of Exercise Training on Reproductive and Cardiometabolic Outcomes in Women with Polycystic Ovary Syndrome: A Pilot Randomized Controlled Trial

Exercise may improve cardiometabolic, reproductive and psychological outcomes in women with Polycystic Ovary Syndrome (PCOS). Clinical Practice Guidelines recommend exercise to treat PCOS, but the most effective exercise prescription is unclear. The aim of this randomized controlled trial was to evaluate the effects of six months of thrice weekly high-intensity interval training (HIIT) and continuous aerobic exercise training (CAET) programs compared with no exercise in previously-inactive women aged 18–40 years with PCOS. The primary outcome was change in ovulation rate. Ovulation was assessed with daily at home ovulation prediction kits, and confirmed with serum progesterone levels. Fisher’s exact test was used to compare groups. Secondary outcomes included change in BMI, waist circumference, blood pressure, A1C, fasting glucose, fasting insulin, and lipids and were analyzed using repeated measures mixed models. 47 women were randomly assigned to no exercise control (n=17), HIIT (n=16), or CAET (n=14). 22/33 (66.7%) women ovulated during the intervention period: no exercise: 8/12 (66.7%), HIIT: 8/11 (72.7%), and CAET: 6/10 (60%); NS between groups. BMI decreased significantly in the CAET group compared with control (-1 kg/m2, p=0.01) and compared with HIIT (-0.9 kg/m2, p=0.04). Mean waist circumference decreased significantly in all groups with no significant difference between groups. There were no significant within- or between- group changes for body weight. No within- or between group differences were identified for mean blood pressure, A1C, fasting glucose, fasting insulin, or triglycerides. Mean LDL-C was significantly different between the HIIT and CAET groups (-0.33 mmol/L, p=0.03), as LDL-C decreased in the HIIT group but not in the CAET group. HDL-C increased in the HIIT group compared with the no exercise group (0.18 mmol/L, p=0.04), with no significant difference between the CAET and no exercise groups (p=0.47). In conclusion, CAET and HIIT interventions in women with PCOS did not affect ovulation rates. CAET and HIIT both were effective at improving anthropometrics and some cardiometabolic health markers in women with PCOS. Further studies are needed to determine optimal exercise prescriptions for reproductive, anthropometric and cardiometabolic outcomes in women with PCOS.

Development of the sheep ovary during fetal and early neonatal life and the effect of fecundity genes

In female sheep fetuses, the mesonephros and genital ridge can be identified at days 20 and 23 of gestation (term = 145 days), respectively. Moreover oogonia can be observed at the genital ridge from as early as day 23. Around day 55 of gestation, some germ cells enter meiosis coincident with the arrival of mesonephric-derived somatic cells (i.e. the rete ovarii). From days 75, 100, 120 and 135 of gestation, primordial (one layer of flattened granulosa cells), primary (one complete layer of cuboidal granulosa cells; early preantral), secondary (preantral) and tertiary (antral) follicles, respectively, develop within the innermost regions of the ovarian cortex. During the early neonatal period highly variable numbers of antral follicles may be present. After examination of Booroola fetuses from day 28 of gestation, it seems that the FecBB gene is associated with retarded development of the heart (day 28) mesonephros (days 30–40) and from day 30 to early neonatal life, the ovary. With respect to the ovary, fewer oogonia (days 30–40), primordial follicles (day 75–90) and growing follicles (day 120 to 6 weeks after birth) have been observed in females carrying the FecB gene. By contrast, the FecB gene is not associated with differences in plasma gonadotrophin or immunoreactive inhibin until early neonatal life. In Inverdale (I) fetuses heterozygous for the FecXI gene (I+), retarded germ cell development was observed at days 40 and 90 of gestation. In putative homozygous carriers (II) of the Inverdale gene, germ cell development appeared normal until day 100, but thereafter from day 120 normal secondary follicles were not observed, although many abnormal follicular-like structures were present. In both I+ and II fetuses no obvious differences in gonadotrophin concentrations have been noted. Collectively, the evidence suggests that the fecundity genes FecBB and FecXI, which affect ovulation rate in sexually mature females, are regulating organ differentiation or germ cell maturation or both processes during fetal life.

Booroolo allele segregation inGaroleMaluro and GM sheep

Garole Sheep of west Bengal (India) is known to carry mutation in an autosomal gent FecB (Boraola allel or FecB + ) on ovine chromosome 6. The mutation is known to affect Ovulation rate and in turn litter size in Garole sheep. The mutated allel is hypothesized to be the original genotype of the breed and by this virtue the sheep produces twins, triplets and quadruplets. To incorporate the character of higher prolificacy in mutation type non-prolific Malpura sheep of semi-arid region of Rajasthan, Garole sheep was used as sire breed in FecB introgression programme started in 1997 at Central sheep and wool Research Institute, Avikanagar. Presence of FecB allel was detected in Garole and GM sheep. The genotype frequencies of homozygous carriers (FecB B+ ) were 0.41 and 0.11 in Garole and GM, respectively. The corresponding Figures for heterozygous (Fecb B+ ) were 0.48 and 0.60 in Garole and GM, respectively.

New genetic polymorphisms in Indian goat BMPR1B gene

Studies on the genetics of prolificacy in small ruminants have highlighted the importance of BMPR1B (bone morphogenetic protein receptor IB) gene in affecting ovulation rate and litter size. Most of the research on BMPR1B gene has revolved around screening sheep and goats for the presence of FecB mutation (A746G) that is associated with hyperprolific phenotype in many breeds around the world. In the present study, an attempt was made to detect polymorphism in the promoter and exonic regions (exon1, 2 and 6 to 9) of BMPR1B gene in 8 indigenous goat breeds (Barbari, Beetal, Black Bengal, Malabari, Jakhrana, Osmanabadi, Sirohi and Ganjam) varying in prolificacy and geographic distribution. Targeted DNA fragments (2612 bp) were obtained through PCR and DNA sequencing methods. BMPR1B promoter region was amplified in two fragments and a 1032 bp length contig was generated for the first time for goats. Two novel SNPs T(-242)C and G(–623)A were identified in the promoter region of caprine BMPR1B gene by sequence alignment. Hundred variations were observed between cattle and goat promoter sequence. The variations did not change or affect any transcription binding sites in promoter of BMPR1B gene. Sequence analysis revealed absence of any polymorphism including the FecB mutation in exonic regions of all the investigated breeds of Indian goats. This is the first report of identification of mutation in regulatory region of BMPR1B gene, which may be helpful for better understanding of the role played by this gene in reproduction of the goat.

Progress on major genes for high fecundity in ewes

The existence of major genes affecting fecund- ity in sheep flocks throughout the world has been demonstrated. Three major genes whose mutations can increase ovulation rate have been discovered, and all related to the transforming growth factor β (TGF-β) superfamily. The mutant FecB of bone morphogenetic protein receptor 1B (BMPR1B) has an additive effect on ovulation rate. Six mutations (FecX I , FecX H , FecX G , FecX B , FecX L , FecX R ) of bone morphogenetic protein 15 (BMP15) related with fertility have been identified that share the same mechanism. All the mutants can increase ovulation rate in heterozygotes and cause complete sterility in homozygotes. Homozygous ewes with two new mutations (FecX Gr , FecX O ) of BMP15 had increased ovulation rate without causing sterility. There are five mutations in growth differentiation factor 9 (GDF9) associated with sheep prolificacy where FecG E and FecG F have additive an effect on ovulation rate and litter size. The newly identified β-1,4-N-acetylgalactosaminyl- transferase 2 (B4GALNT2) gene of FecL is proposed as a new mechanism of ovulation rate regulation in sheep. Woodlands is an X-linked maternally imprinted gene which increases ovulation rate. In addition, several putative major genes need to be verified. This review is focused on the identification of the mutations and mechanisms whereby the major genes affecting ovulation rate.

Follicle development, endocrine profiles and ovulation rate in adult Merino ewes: effects of early nutrition (pre- and post-natal) and supplementation with lupin grain

In adult ewes, we tested whether ovarian function, including the response to short-term supplementation, was affected by the nutrition of their mothers during the pre-/post-natal period. A 2×2 factorial design was used with nutrition in early life (low or high) and a 6-day supplement (with or without) as factors. All ewes received three prostaglandin (PG) injections 7 days apart, and the supplement (lupin grain) was fed for 6 days from 2 days after the second until the third PG injection. We measured reproductive and metabolic hormones, studied follicle dynamics (ultrasonography), and evaluated granulosa cell numbers, aromatase activity and oestradiol (E2) concentrations in follicular fluid in healthy follicles at days 3 and 7 of supplementation. Ovulation rate was increased by 25% by exposure to high pre-/post-natal nutrition (1.5 vs 1.2; P<0.05), in association with a small decrease in FSH concentrations (P=0.06) and a small increase in insulin concentrations (P=0.07). The number of healthy antral follicles was not affected. Acute supplementation increased the number of granulosa cells (3.7±0.2 vs 3.0±0.2 million; P<0.05) in the largest follicle, and the circulating concentrations of E2 (4.6±0.3 vs 3.9±0.3 pmol/l; P<0.05) and glucose (3.4±0.03 vs 3.3±0.03 mmol/l; P<0.01). Both early life nutrition and acute supplementation appear to affect ovulation rate through changes in glucose-insulin homoeostasis that alter follicular responsiveness to FSH and therefore E2-FSH balance.

Using sheep lines with mutations in single genes to better understand ovarian function

Livestock populations have been subjected to strong selection pressure to improve reproductive success, and this has led to the identification of lines of animals with increased fecundity. These animals provide a rich biological resource for discovery of genes and regulatory mechanisms that underpin improved reproductive success. To date, three genes, all related to the transforming growth factor β pathway, have been identified as having mutations that lead to alterations in ovulation in sheep. In addition, several other sheep lines have been identified with putative mutations in single genes with major effects on ovulation rate. This review is focused on the identification of the mutations affecting ovulation rate and how these discoveries have provided new insights into control of ovarian function.

Short communication: A missense mutation in the PROP1 (prophet of Pit 1) gene affects male fertility and milk production traits in the US Holstein population

In previous studies, we reported significant associations of the POU1F1 pathway genes with reproduction and production traits in several dairy cattle populations. Polymorphisms in genes of this pathway were found to be associated with both female and male fertility traits in dairy cattle. The POU1F1 gene is a direct downstream target for the regulation of the prophet of Pit1 (PROP1) gene, also known as PROP paired-like homeobox 1. Interestingly, the position of PROP1 coincides with a quantitative trait locus affecting ovulation rate in cattle. Therefore, the objective of this study was to investigate whether PROP1 affects fertility and milk production traits in Holstein cattle. Using the DNA pooling sequencing approach, a missense single nucleotide polymorphism that replaces a histidine amino acid with an arginine was detected in exon 3 of PROP1. The arginine allele was found to be associated with a decrease in sire conception rate and an increase in productive life, protein yield, and net merit index in a population of 1,951 Holstein bulls. The transcription factors produced from the histidine and arginine isoforms are known to have different transcription, DNA binding, and regulation activities. As such, we propose that the association of the arginine isoform with decreased bull fertility is likely caused by reduced activity of this allele in male functions. The findings of this study suggest PROP1 polymorphisms as candidates in selection programs for fertility, health, and milk production traits in dairy cattle.

Post-weaning Altrenogest treatment in primiparous sows; the effect of duration and dosage on follicular development and consequences for early pregnancy

Our objective was to investigate follicle development in sows during and after different Altrenogest treatments post-weaning and relate this to subsequent ovulation rate and embryonic development. Primiparous UPB sows ( n = 47) were randomly assigned to (weaning = Day 0): control (no Altrenogest, n = 12), RU8-15 (15 mg of Altrenogest, Day-1 till Day 7, n = 12), RU8-20 (20 mg of Altrenogest, Day-1 till Day 7, n = 12) or RU15-15 (15 mg of Altrenogest, Day-1 till Day 14, n = 11). From weaning onwards, trans-abdominal ultrasound was performed daily. Sows were slaughtered on Day 4 or 5 after ovulation. Follicle size increased during Altrenogest treatment and reached a plateau around Day 6, regardless of dose (4.6 ± 1.5, 4.6 ± 1.6 and 4.6 ± 1.6 mm for RU8-15, RU8-20 and RU15-15, respectively). This increase resulted in larger follicles ( P = 0.0002) at the onset of the follicular phase (i.e. time of weaning for control sows and 24 h after last administration of Altrenogest for treated sows); 4.8 ± 1.8, 4.8 ± 1.4, 4.9 ± 0.9 mm and 2.9 ± 0.8, for RU8-15, RU8-20, RU15-15 and controls, respectively. Pre-ovulatory follicle size tended ( P = 0.07) to be larger for treated animals (7.9 ± 2.4, 7.9 ± 0.7, 8.6 ± 1.3 and 6.9 ± 0.9 mm for RU8-15, RU8-20, RU15-15 and controls, respectively). The interval follicular phase-oestrus was shorter ( P = 0.005) for treated animals. Treatment did not affect ovulation rate or early embryonic development. However, for treated animals, the increase in follicle size during treatment was positively related with ovulation rate ( P = 0.05). In conclusion, post-weaning treatment with Altrenogest of first litter sows influenced follicle size and shortened the follicular phase, but did not affect ovulation rate or early embryonic development.

Genetic Aspects of Reproduction in Sheep

Maintenance of high levels of realized fertility (defined as the percentage of ewes that lamb) and appropriate levels of fecundity are critical for efficient sheep production. The optimal level of fecundity in most situations is well below the maximum attainable level and can be targeted by combining selection among and within breeds with use of an expanding array of single-gene mutations affecting ovulation rate and litter size. The heritability of litter size is approximately 0.10, allowing changes of up to 2%/year from simple mass selection. Mutations in several genes associated with the transforming growth factor beta superfamily (BMPRIB, GDF9 and sex-linked BMP15) can increase ovulation rates by 0.7-1.5 ova in heterozygous ewes. However, ewes that are homozygous for BMP15 or GDF9 mutations are sterile, so use of these mutations requires carefully structured breeding programmes. Improvements in fertility may be critical for autumn lambing or programmes that aspire to lamb throughout the year. Selection to improve fertility in spring matings has been successful; selected adult ewes have lambing rates of 80-85% in October and early November. The selected ewes have a dramatically reduced seasonal anestrus, and many ewes continue to cycle during spring and summer. Major genes affecting seasonal breeding have not been identified in sheep. Polymorphisms in the melatonin receptor 1a gene appear to be associated with seasonal breeding in some, but not all breeds. However, functional genomic studies of genes associated with circadian and circannual rhythms have potential to reveal additional candidate genes involved in seasonal breeding.

Effect of soluble and insoluble dietary fiber on embryo survival and sow performance1

Two experiments were conducted to evaluate the effects of soluble (SF) and insoluble (ISF) dietary fiber during gestation on embryo survival and sow performance. In Exp. 1, 43 gilts were assigned randomly to 1 of 4 experimental diets: a corn-soybean meal control (C; 1.16% SF, 9.98% ISF); a 30% oat bran high in SF (HS; 3.02% SF, 10.06% ISF); a 12% wheat straw diet high in ISF (HIS; 1.08% SF, 18.09% ISF); and a 21% soybean hull diet (HS + HIS; 2.46% SF, 24.55% ISF). Gilts were fed the experimental diets based on their initial BW to meet their daily nutrient requirements. At estrus, gilts were inseminated artificially 3 times using pooled semen. Reproductive tracts were harvested 32 d postmating (range = 28 to 35 d). Statistical analysis of data included the effects of diet with days of gestation as a covariate. There were no differences in ovulation rate among gilts fed the experimental diets (avg. = 14.1). Number of live embryos was less for HIS and HS + HIS gilts compared with C and HS (9.9 and 9.1 vs. 11.9 and 10.6, respectively; P < 0.05). Total embryo survival rate (P < 0.05) was less for gilts fed HS + HIS compared with those fed the C and HS diets. These results suggest that high dietary ISF might decrease the total embryo survival rate without affecting ovulation rate. In Exp. 2, 716 sows were used in 3 concurrent trials. In trial 1, diets included a corn-soybean meal control (C; 0.43% SF, 10.50% ISF; n = 122) or a 31% oat bran diet (HS; 1.93% SF, 8.87% ISF; n = 124). In trial 2, diets included a C (n = 97) or a 13% wheat straw diet (HIS; 1.10% SF, 17.67% ISF; n = 119), and in trial 3 sows were fed a C (n = 123) or a 21% soybean hull diet (HS + HIS; 1.50% SF, 17.77% ISF; n = 131). All diets were offered to sows beginning 2 d postmating. All sows had ad libitum access to a standard lactation diet. Statistical analysis included the effects of diet, parity group, genetic line, and season as well as their interactions. The inclusion of SF and ISF in gestation diets did not affect litter size. Sows fed the HS + HIS diet had a greater ADFI and lost less BW during lactation (P < 0.01) than sows fed C. Under the conditions of this study, feeding gestating sows increased levels of SF and ISF from d 2 after breeding to d 109 of gestation did not increase litter size.