Improvement Of Reproductive Performance Research Articles

Effects of flaxseed-rich diet on reproductive performance in estrous-synchronized Baluchi ewes.

The purpose of this study was to compare the effects of using different levels of flaxseed in diets on the reproductive performance of estrous-synchronized Baluchi ewes (para 3). Diets contained either basal diet (control) or different levels of extruded flaxseed (2%, 5%, 7%, 10%, and 12%) and were fed from lambing to 60 days after lambing. The ewe estrus cycles were synchronized using controlled internal drug release (CIDR) for 14 days starting from day 16 of fat supplementation. The rams were introduced 24 h after CIDR removal. The ewes fed control diets had the highest mean dry matter intake (1,800±35 g) which was declined with the increase of flaxseed levels. The experimental diets exerted no effects of urea concentration in blood plasma. However, plasma glucose concentration was lower (p <0.05) in the ewes fed the control diet and 2% flaxseed, compared to those in other groups. Nonetheless, there was no difference among the ewes fed 5%, 7%, 10%, and 12% flaxseed in terms of plasma glucose concentrations (p <0.05). The ewes fed 2% flaxseed had the highest level of plasma triglyceride concentration among other groups. In addition, the control group had the lowest level of plasma total cholesterol and low-density lipoproteins concentration in comparison to other groups (p <0.05). However, plasma nonesterified fatty acids and β-hydroxybutyrate concentrations were similar among the groups (P>0.05). The mean interval between CIDR removal and the exhibition of estrus ranged from 30 to 40 h with the shortest interval being recorded in the ewes fed 12% flaxseed (p <0.05). The control group had the lowest number of follicles on estrus day among other groups (p <0.05). Furthermore, the ewes fed 10% and 12% flaxseed had the highest ovulation, pregnancy, and lambing rates, compared to other groups (p <0.05). In conclusion, the findings revealed that feeding the ewes with 10% and 12% flaxseed resulted in the improvement of reproductive performance.

Long-Term Effect of Environmental Enrichment on Reproductive Performance of Swiss Webster Mice and Their Female Offspring.

Simple SummaryThe aim of this study was to evaluate the effect of the implementation of an environmental enrichment (EE) plan on reproductive performance in mice, applied during one year period in Swiss Webster breeders and their female offspring used as recipients for embryo transfer. Birth rate, litter size, pups’ weight at weaning, interlitter interval and time to first litter were compared against a control group that did not receive EE. In mice breeders, EE significantly increased pups’ weight compared to control group (p < 0.01), without changing any other reproductive parameters. In the offspring females used as recipients, EE did not modify reproductive parameters. Our results demonstrate that this enrichment plan, which is usually applied in mouse facilities for animal well-being, enhances pup’s weight at weaning, with no negative effects on the reproductive performance of Swiss Webster mice.The aim of this study was to evaluate the effect of an environmental enrichment (EE) plan on the reproductive performance of Swiss Webster mice and their female offspring used as recipients for embryo transfer. A total of 54 breeder mice and 60 F1 females, used as foster mothers, were allocated in two experimental groups to receive or not receive EE for physical well-being. Reproductive outcomes of the Swiss trios such as birth rate and pup number, litter size, pups’ weight at weaning, interlitter interval and time to first litter were analyzed. Environmental enrichment significantly increased pups weight from breeding trios compared to the control group (14.4 ± 0.1 vs. 13.8g ± 0.1, EE vs. control, respectively; p < 0.01). Other parameters did not differ between both groups. Reproductive parameters of female offspring used as recipients for embryo transfer did not differ among groups subjected or not to EE. These data demonstrate that the EE protocol applied in Swiss Webster breeder mice positively enhanced pups weight, and did not interfere with other reproductive outcomes. In conclusion, this study supports the implementation of EE plans usually applied for animal welfare in mouse facilities with slight improvement in reproductive performance.

Polymorphisms in the ASMT and ADAMTS1 gene may increase litter size in goats

Prolificacy of most local goat breeds in China is low. Jining Grey goat is one of the most prolific goat breeds in China, it is an important goat breed for the rural economy. ASMT (acetylserotonin O‐methyltransferase) and ADAMTS1 (ADAM metallopeptidase with thrombospondin type 1 motif) are essential for animal reproduction. Single nucleotide polymorphisms (SNPs) of ASMT and ADAMTS1 genes in the highly prolific breed (Jining Grey goats), medium prolific breed (Boer goats and Guizhou White goats) and low prolific breeds (Angora goats, Liaoning Cashmere goats and Inner Mongolia Cashmere goats) were detected by polymerase chain reaction‐restriction fragment length polymorphism and sequencing. Two SNPs (g.158122T>C, g.158700G>A) of ASMT gene and two SNPs (g.7979798A>G, g.7979477C>T) of ADAMTS1 gene were identified. For g.158122T>C of ASMT gene, further analysis revealed that genotype TC or CC had 0.66 (p < 0.05) or 0.75 (p < 0.05) kids more than those with genotype TT in Jining Grey goats. No significant difference (p > 0.05) was found in litter size between TC and CC genotypes. The SNP (g.158122T>C) caused a p.Tyr298His change and this SNP mutation resulted in changes in protein binding sites and macromolecule‐binding sites. The improvement in reproductive performance may be due to changes in the structure of ASMT protein. For g.7979477C>T of ADAMTS1 gene, Jining Grey does with genotype CT or TT had 0.82 (p < 0.05) or 0.86 (p < 0.05) more kids than those with genotype CC. No significant difference (p > 0.05) was found in litter size between CT or TT genotypes. These results preliminarily indicated that C allele (g.158122T>C) of ASMT gene and T allele (g.7979477C>T) of ADAMTS1 gene are potential molecular markers which could improve litter size of Jining Grey goats and be used in goat breeding.

The impact of swine influenza and how to control it on farm

Swine influenza (SIV) can reduce productivity on farm and therefore can have a large economic impact also. The virus has four common lineages in swine, H1avN1av, H1huN2, H3N2 and H1pdmN1pdm (the pandemic strain). The virus invades the respiratory tract and therefore the majority of clinical signs are of respiratory nature, including sneezing, coughing and nasal discharge, which can also be accompanied by fever and lethargy. Diagnosis of the disease is important to determine the strain on the farm and therefore implement a control plan which may include biosecurity and hygiene measures in combination with vaccination. Vaccination has been shown to be effective in reducing the clinical signs, lung lesions and the viral shedding. Vaccination of the breeding herd can result in an improvement in reproductive performance, such as a reduction in the return to oestrus rate and an increase in the number of piglets born alive. Control of SIV should be a combined approach to achieve the best results on farm.

Reproductive performance of pandemic influenza A virus infected sow herds before and after implementation of a vaccine against the influenza A (H1N1)pdm09 virus

BackgroundReproductive failure in sow herds due to infection with influenza A viruses has been described in the literature, but only a few studies have focused on the pathogenesis and the clinical signs of the infection. Case reports indicate an association between infections with influenza A viruses and reduced reproductive performance, although it has been difficult to experimentally reproduce the clinical outcome of poor reproductive performance. The aim of the present longitudinal field study was to compare the reproductive performance parameters before and after the implementation of vaccination against the influenza A (H1N1)pdm09 virus in sow herds infected with pandemic influenza A virus. Therefore, farm-specific data of 137 sow herds in Germany, including 60,153 sows, as well as the clinical presentation of the infection were surveyed via questionnaire. Furthermore, average performance parameters (return to oestrus rate, abortion rate, stillbirth rate, number of piglets born alive per litter, preweaning mortality rate and number of piglets weaned per sow per year) were recorded for 6 months before vaccination and 6 months after completion of primary vaccination.ResultsIn 79.8% of the farms, the clinical presentation of the infection was characterised by a reduced reproductive performance. These findings were confirmed by analysis of the performance parameters, which revealed a significant decline in the return to oestrus rate (p < 0.001), abortion rate (p < 0.001) and preweaning mortality rate (p = 0.023) and a significant increase of the number in piglets born alive (p = 0.001) and piglets weaned per sow per year (p < 0.001) after immunisation. The stillbirth rate did not change significantly.ConclusionThe present study represents the first attempt to demonstrate the association of influenza A virus infection, vaccination and the alteration in reproductive performance parameters, investigating a large number of cases. The results show that by vaccinating against the influenza A (H1N1)pdm09 virus, an improvement in reproductive performance can be achieved in sow herds infected with pandemic influenza A virus. Additionally, the large number of herds that were affected by poor reproductive performance after infection with the aforementioned virus confirms the assumption of an association between pandemic influenza A virus and reproductive losses.

Effects of oestrous synchronization with altrenogest in gilts on endometrial and embryonic characteristics

The use of altrenogest (ALT) supplementation for oestrous synchronization improves subsequent reproductive performance of gilts and sows. However, the causes of this improvement in reproductive performance after ALT treatment are not fully/clearly understood. The objective of this study was to evaluate the effects of ALT supplementation for oestrous synchronization in gilts on the endometrial glands and embryonic development characteristics at 28 days of pregnancy. Pregnant gilts were divided into two experimental treatments: Control (did not receive ALT; n = 9 gilts) and ALT (ALT feeding at 20 mg/day for 18 days; n = 9 gilts). At 28 days of pregnancy, six gilts from each treatment were slaughtered, and reproductive tracts were immediately evaluated. There was no statistical difference (P > 0.05) between treatments regarding ovulation rate, number of embryos, number of vital embryos and number of non-vital embryos. Embryo weight, length and embryonic vesicle weight were lower in ALT treatment compared with Control (P < 0.01), and it was lower in the cervical uterine region compared with apex uterine region, respectively (P < 0.05). Higher values of gland duct area, gland duct perimeter, percentage of the glandular area and total endometrial area were observed in ALT treatment compared with Control (P < 0.05). The use of ALT during 18 days for oestrous synchronization in gilts increased the gland duct area, perimeter and total endometrial area but did not increase the embryo number and embryo size at day 28 of pregnancy.

Genetic parameters of reproductive traits from artificial insemination records of Japanese Black cows

Decline in reproductive performance directly affects the cost of calf production in the beef industry. The objective of this study was to estimate heritability, repeatability and genetic correlation among female reproductive traits, and to determine the most appropriate trait for improving reproductive performance in Japanese Black cows. The traits studied were; non-return rate (NRR), number of inseminations (IN), days from first to successful insemination (FS), gestation length (GL), days from calving to first insemination (CF), days open (DO), pregnancy rate (PR), calving interval (CI) and age at calving (AC). Data across multiple parities were analyzed by using a multiple-trait model under which the performance of a trait in different parities was treated as a different trait, and by using a repeatability model for treating records of multiple parities as repeated measurements. AC comprises age at first calving (AFC), age at second calving (ASC) and age at third calving (ATC) under the multiple-trait model. Genetic parameters were estimated by restricted maximum likelihood (REML). The estimated heritability of traits showed little variation among parities. Heritability of AC was higher than of the other traits, although it was lower in later parities; 0.158, 0.107 and 0.088 for AFC, ASC and ATC, respectively. The highest repeatability was observed for CF (0.142) and the lowest for FS (0.036). The genetic correlations between the same traits across parities were generally high, ranging from 0.72 to 0.99. The lowest genetic correlation in absolute values was observed between CF and IN (-0.075) and the highest between DO and CI (0.957). AFC was concluded to be the most promising trait for genetic evaluation of female reproductive traits because it demonstrated higher heritability and moderate to high genetic correlations with NRR, GL, CF, DO, PR, CI, IN and FS. Selection of AFC will provide higher genetic improvement in reproductive performance of Japanese Black cows.

The impact of melatonin administration on the fertility performance and several relating parameters during the breeding season in the Arabi ewes

A total of twenty-four healthy ewes aged between 2-3 years old and weighed about 35.09 kg of body weight were divided randomly into four groups (6 animals for each group). The first group included the non-treated control group, while the other three groups were subjected to various oral doses of melatonin 9 mg, 12 mg and 15 mg/head, respectively. All treatments were applied at 6 o'clock in the morning, to investigate the effect of treatment with melatonin during breeding season on reproductive performance and levels of some biochemical parameters in Arabi ewes from 1 May to 1 October 2017. Blood samples 7ml were collected after one hour of treatment and then monthly during the pregnancy months to determine the concentrations of biochemical parameters. After Postpartum, lambed ewes/lambs number, birth weight, placenta empty weight and cotyledon number were recorded. The results showed significant (P<0.05) improvement in reproductive performance (fertility percentage, twinning rate and the number of offspring) when ewes administrated melatonin at two doses (12 and 15 mg/ head). Also, melatonin administration caused significant (P<0.05) decrease in the concentrations of thyroxin, cortisol, and cholesterol. Conversely, there was a significant increase (P<0.05) in glucose concentration after 1 hour of treatment. The concentrations of thyroxin, cortisol, cholesterol, and vitamin C increased significantly (P<0.01) in early-gestation compared with mid and late-gestation, while the concentrations progesterone and glucose increased significantly (P<0.05) in mid-gestation compared with early and late-gestation. In conclusion, melatonin administration at doses 12 and 15 mg/ head improves ewe reproductive performance (fertility percentage, twinning rate and the number of born lambs). Additionally, the gestation stage has a negative effect on the concentrations of thyroxin, cholesterol and vitamin C.

Enhancing reproductive performance in domestic dairy water buffalo (Bubalus bubalis)

The purpose of the review is to describe the factors that affect fertility in domestic water buffalo (Bubalus bubalis) and the techniques that enable an improvement in reproductive performance. On Italian and Latin American farms where natural mating is practiced and bulls are always present in the herd, the inter-calving interval is approximately 400 days and the culling rate is lower than 15%. The buffalo has a tendency for seasonal reproductive activity. Reproduction is favoured when there is a decrease in day length. Ovarian activity stops if conception does not occur within 3 to 5 ovarian cycles. It is important, therefore, that appropriate management of the transition period is practiced, particularly with respect to the hygienic conditions of the uterus. In tropical countries located north of the equator, feed deficiencies and heat stress are considered the main factors that lead to poor fertility in the summer. In Pakistan, for example, the increase in body condition score during the autumn was associated with the commencement of the breeding season in buffaloes. Anoestrus is observed also in Italy, however, where the average daily temperature during the same period is 13.5 to 23.5 degrees C and feeding is constant throughout the year. The only common element between the two areas is the progressive increase in daylight hours between April and June and the day length greater than 12 hours up to September. In Italian herds that apply an out-of-season breeding strategy, an improvement in fertility (measured as the percentage of corpora lutea corresponding to subsequent pregnancy) is observed when water pools are present on the farm. This demonstrates that an improvement in environmental conditions reduces the incidence of embryonic mortality and/or abnormal cycles. To summarize, in the absence of serious nutritional problems, an improvement in environmental conditions increases fertility in buffalo.

Age-related improvements in fecundity are driven by the male in a bird with partially reversed sex roles in parental care.

Age-related improvement in reproductive performance is widespread in vertebrates and constraints at young ages are a common cause. The sex that invests energetically more in reproduction, typically the female, is predicted to show stronger age-related performance but the effect of the male's age on reproduction has often been ignored. I studied age-related reproduction of both sexes in northern flickers, in which males invest more parental care than females, predicting that the effect of age would be stronger in males than in females. Longitudinal data on individuals collected during an 18-year field study confirmed this prediction. Laying dates for females improved only between the first 2years of her life and no other reproductive parameter changed over her lifetime when the male's age was statistically controlled. In contrast, males improved up to age five for laying date, clutch size, hatching success and fledging success. Partner familiarity (fidelity) was further associated with earlier laying, larger clutches, improved fledging success and more fledglings. There was significant assortative pairing by age but there is apparently little benefit for males to choose older females, but a benefit to females with older males. Females appear to strategically lay larger clutches when paired to old males which invest more in paternal care than younger males. This is the first example of clutch size being influenced by only male age and not female age in any bird and suggests that sex roles in parental care are important determinants of aging patterns in vertebrates with diverse life histories.

Effect of vaccination with a porcine reproductive and respiratory syndrome subunit vaccine on sow reproductive performance in endemic farms

The objective of this field study was to evaluate the reproductive performance of sows after vaccination with a porcine reproductive and respiratory syndrome (PRRS) subunit vaccine (PRRSFREE PRRS subunit vaccine,...

A modified-live porcine reproductive and respiratory syndrome virus (PRRSV)-1 vaccine protects late-term pregnancy gilts against heterologous PRRSV-1 but not PRRSV-2 challenge.

The objective of this study was to determine the efficacy of a commercially available porcine reproductive and respiratory syndrome virus (PRRSV)-1 modified-live virus (MLV) vaccine against PRRSV-1 and PRRSV-2 challenge in late-term pregnancy gilts. Gilts were vaccinated with the PRRSV-1 MLV vaccine at 4weeks prior to breeding and then challenged intranasally with PRRSV-1 or PRRSV-2 at 93days of gestation. After PRRSV-1 challenge, vaccinated pregnant gilts had a significantly longer gestation period, significantly higher numbers of live-born and weaned piglets and a significantly lower number of stillborn piglets at birth compared to unvaccinated pregnant gilts. No significant improvement in reproductive performance was observed between vaccinated and unvaccinated pregnant gilts following PRRSV-2 challenge. Vaccinated pregnant gilts also exhibited a significantly improved reproductive performance after challenge with PRRSV-1 compared to vaccinated pregnant gilts following PRRSV-2 challenge. The PRRSV-1 MLV vaccine was able to reduce PRRSV-1 but not PRRSV-2 viremia in pregnant gilts. Vaccinated gilts also showed a significantly higher number of PRRSV-1-specific IFN-γ-secreting cells (IFN-γ-SC) compared to PRRSV-2-specific IFN-γ-SC. The data presented here suggest that the vaccination of pregnant gilts with a PRRSV-1 MLV vaccine provides good protection against PRRSV-1 but only limited protection against PRRSV-2 challenge in late-term pregnancy gilts based on improvement of reproductive performance, reduction in viremia and induction of IFN-γ-SC.

Genome-wide association study of Stayability and Heifer Pregnancy in Red Angus cattle.

Reproductive performance is the most important component of cattle production from the standpoint of economic sustainability of commercial beef enterprises. Heifer Pregnancy (HPG) and Stayability (STAY) genetic predictions are 2 selection tools published by the Red Angus Association of America (RAAA) to assist with improvements in reproductive performance. Given the importance of HPG and STAY to the profitability of commercial beef enterprises, the objective of this study was to identify QTL associated with both HPG and STAY in Red Angus cattle. A genome-wide association study (GWAS) was performed using deregressed HPG and STAY EBV, calculated using a single-trait animal model and a 3-generation pedigree with data from the Spring 2015 RAAA National Cattle Evaluation. Each individual animal possessed 74,659 SNP genotypes. Individual animals with a deregressed EBV reliability > 0.05 were merged with the genotype file and marker quality control was performed. Criteria for sifting genotypes consisted of removing those markers where any of the following were found: average call rate less than 0.85, minor allele frequency < 0.01, lack of Hardy-Weinberg equilibrium (P < 0.0001), or extreme linkage disequilibrium (r2 > 0.99). These criteria resulted in 2,664 animals with 62,807 SNP available for GWAS. Association studies were performed using a Bayes Cπ model in the BOLT software package. Marker significance was calculated as the posterior probability of inclusion (PPI), or the number of instances a specific marker was sampled divided by the total number of samples retained from the Markov chain Monte Carlo chains. Nine markers, with a PPI ≥ 3% were identified as QTL associated with HPG on BTA 1, 11, 13, 23, and 29. Twelve markers, with a PPI ≥ 75% were identified as QTL associated with STAY on BTA 6, 8, 9, 12, 15, 18, 22, and 23.

Applications of ultrasonography in ruminants (II): Female reproductive system - A review

Ultrasonography is a non-invasive imaging method used for assessing pathological and physiological situations, successfully applied in the imaging of the reproductive tract of ruminants. The contribution of this diagnostic method has been essential in understanding the function of the reproductive system and especially that of the ovarian cycle. For the examination of the reproductive system of female ruminants the most frequently applied equipment is that of type B-mode real time, with linear probe and frequencies of 3.0? 5.0 and 7.5 MHz. In cattle, the examination is conducted primarily through the rectal, while in small ruminants it can also be performed transabdominal.In non-pregnant animals the ultrasound scanning aims at the examination of the cervix, the uterus and the ovaries allowing the determination of the stage of the estrus cycle, or the diagnosis of certain abnormalities of the reproductive system (ovarian cyst, anoestrus, etc). During gestation, ultrasonography finds numerous applications in ruminants, such as early pregnancy diagnosis* determination of the number and the sex of the fetuses, assessment of the stage of gestation, control of fetal vitality, etc. Ultrasonography has also been used for the selection of animals for reproduction contributing in the improvement of reproductive performance. Biotechnology is another area where ultrasound scanning is extensively used (ovum pick-up, embryo transfer, etc). Today the use of ultrasonography is widely spread in ruminants aiming at real time and dynamic assessment of the reproductive system. The cost of equipment has been reduced over the past years, enabling the veterinarians to benefit of its potentials.

15 Effects of Timed Artificial Insemination Protocol Using Prostglandin F2α and Estradiol Benzoate on Conception Rate in High-Producing Dairy Cows

For several years, milk production per Holstein cow has been increasing while reproductive performance has declined worldwide. Timed AI (TAI) protocols with synchronization of oestrus and ovulation are tools for the improvement of reproductive performance in high producing dairy herds. In protocols for synchronization of oestrus and ovulation, oestradiol benzoate (EB) has been used to increase the number of animals that show oestrous behaviour, synchronize ovulation, and improve conception rate (CR). The objective of this study was to compare a simple oestrus synchronization and TAI protocol using prostaglandin F2α (PG) and EB with a more complicated TAI protocol or oestrus detection and AI on CR in high-producing Holstein cows. The study was conducted from 2014 to 2016, using 1,036 Holstein cows from 3 commercial dairy herds in central Hokkaido, Japan. The average parity number was 2.6 ± 1.5, and days open averaged 152.2 ± 82.0 days. The average milk yield (305 days) was 11,348 ± 1,619 kg. Oestrus synchronization of cows was achieved using PG followed by EB and TAI (PG was given to cows with a cutoff for CL diameter of &gt;20 mm by ultrasonography; EB (1 mg) was administered 24 h later and AI was carried out 24 to 48 h after EB injection), or by Heatsynch + CIDR [gonadotropin-releasing hormone (GnRH) injection and CIDR insertion at random stages of the oestrous cycle, CIDR removal, and PG injection 7 days later, EB injected 24 h after CIDR removal, and TAI 24 to 32 h after EB injection]. Cows observed in natural oestrus were used as controls. All cows were inseminated after the onset of standing heat or removal of the tail chalk (Paintstik®, LA-CO Industries, Elk Grove Village, IL, USA). Pregnancy diagnoses were performed using ultrasonography between 30 and 45 days after AI. The CR were compared using chi-square test. The CR (no. of pregnant cows/no. of total cows in the treatment group) of the natural oestrus group, PG + EB, and Heatsynch + CIDR cows were 39.2% (302/771), 38.7% (48/124), and 31.2% (44/141), respectively. Overall CR for the 3 groups was 38.0%. There were no significant differences in CR among the 2 groups (P &gt; 0.07). These results show that a simple oestrus synchronization protocol with injection of PG followed by EB can be used effectively for high-producing dairy herds, yielding a satisfactory CR similar to that obtained with the Heatsynch + CIDR protocol or natural oestrus.

Influences of dietary selenium, zinc and their combination on semen characteristics and testosterone concentration in mature rams during breeding season

ABSTRACTThis study was conducted to determine the effect of dietary supplementation of organic zinc (Availa®Zn100) and selenium (Availa®Se1000) on semen characteristics, testes measures and serum testosterone concentration. Twenty Sanjabi rams (50.01 ± 5.6 kg) were randomly divided into four equal groups, given the basal diet as control (C) or supplemented with 0.3 mg/kg Se (SE) or 40 mg/kg Zn (ZN) or 40 mg/kg Zn plus 0.3 mg/kg Se (ZS) for 120 days experiment (from July to November). The semen samples and blood samples were collected every 3 weeks and scrotal circumference was measured every 15 days. The results indicated that scrotal circumference and testosterone concentrations did not differ due to treatment (P > .05). In contrast, semen characteristics were affected by ZS supplementation. The sperm density and total sperm number increased (P < .05) in ZS group. In addition, the progressive sperm motility was higher in ZS (P < .05) than those of SE and C groups. It is concluded that ZS treatment can improve semen characteristics, which may result in overall improvement in reproductive performance of treated Sanjabi rams during the breeding season.

Effect of short term diet restriction on gene expression in the bovine hypothalamus using next generation RNA sequencing technology

BackgroundNegative energy balance (NEB) is an imbalance between energy intake and energy requirements for lactation and body maintenance affecting high-yielding dairy cows and is of considerable economic importance due to its negative impact on fertility and health in dairy herds. It is anticipated that the cow hypothalamus experiences extensive biochemical changes during the early post partum period in an effort to re-establish metabolic homeostasis. However, there is variation in the tolerance to NEB between individual cows. In order to understand the genomic regulation of ovulation in hypothalamic tissue during NEB, mRNA transcriptional patterns between tolerant and sensitive animals were examined. A short term dietary restriction heifer model was developed which induced abrupt onset of anoestrus in some animals (Restricted Anovulatory; RA) while others maintained oestrous cyclicity (Restricted Ovulatory; RO). A third control group (C) received a higher level of normal feeding.ResultsA total of 15,295 genes were expressed in hypothalamic tissue. Between RA and C groups 137 genes were differentially expressed, whereas between RO and C, 32 genes were differentially expressed. Differentially expressed genes were involved in the immune response and cellular motility in RA and RO groups, respectively, compared to C group. The largest difference between groups was observed in the comparison between RA and RO heifers, with 1094 genes shown to be significantly differentially expressed (SDE). Pathway analysis showed that these SDE genes were associated with 6 canonical pathways (P < 0.01), of which neuroactive ligand-receptor interaction was the most significant. Within the comparisons the main over-represented pathway functions were immune response including neuroprotection (CXCL10, Q1KLR3, IFIH1, IL1 and IL8; RA v C and RA v RO); energy homeostasis (AgRP and NPY; RA v RO); cell motility (CADH1, DSP and TSP4; RO v C) and prevention of GnRH release (NTSR1 IL1α, IL1β, NPY and PACA; RA v RO).ConclusionsThis information will assist in understanding the genomic factors regulating the influence of diet restriction on fertility and may assist in optimising nutritional and management systems for the improvement in reproductive performance.

Evaluation of the effect of a porcine reproductive and respiratory syndrome (PRRS) modified-live virus vaccine on sow reproductive performance in endemic PRRS farms

The efficacy of a porcine reproductive and respiratory syndrome (PRRS) modified-live virus vaccine in reproductive performance was evaluated under field conditions. Three PRRS endemic farms were selected based on their history of PRRS-associated reproductive failures. On each farm, a total of 40 sows were randomly allocated to either vaccinated (n=20) or unvaccinated (n=20) groups. Sows were vaccinated six weeks prior to breeding. Clinical data showed a significant improvement in reproductive performance in vaccinated sows. Sows in the vaccinated groups had a significantly (P<0.05) reduced number of stillborn piglets in all 3 farms. Sows in the vaccinated groups also had a significantly (P<0.05) higher number of live-born piglets in one of the farms. Sows in the vaccinated groups had a significantly (P<0.05) higher number of weaned piglets in two of the farms. Premature farrowing, one of the late gestation symptoms of PRRS, was also reduced due to vaccination as suggested by the increase in gestation length and the reduction in the number of stillborn piglets. No adverse systemic or local side effects relative to vaccination were observed during the entire gestation. No vaccine strain was detected in the vaccinated sows from all three farms at 70 and 114days post vaccination and in live-born piglets at the time of farrowing. Vaccination of sows with this PRRS vaccine was effective in improving reproductive performance in endemic PRRS farms.

Use of haplotypes to identify regions harbouring lethal recessive variants in pigs

BackgroundLethal recessive genetic variants are maintained at relatively low frequencies in a population in the heterozygous state, but by definition are fatal and therefore unobserved in the homozygous state. Since haplotypes allow the tagging of rare and untyped genetic variants, they have potential for studying lethal recessive variants. In this study, we used a large commercial population to identify putative lethal recessive haplotypes that impact either the total number born (TNB) or the number born alive (NBA) as a proportion of the total number born (NBA/TNB). We also compared the use of haplotypes with a single nucleotide polymorphism (SNP)-by-SNP approach and examined the benefits of using additional haplotypes imputed from low-density genotype data for the detection of lethal recessive variants. Candidate haplotypes were identified using population-wide haplotype frequencies and within-family analyses. These candidate haplotypes were subsequently assessed for putative lethal recessive effects on TNB and NBA/TNB by comparing carrier-to-carrier matings with carrier-to-non-carrier matings.ResultsUsing both medium-density and imputed low-density genotype data six regions were identified as containing putative lethal recessive haplotypes that had an effect on TNB. It is likely that these regions were related to at least four putative lethal recessive variants, each located on a different chromosome. Evidence for putative lethal recessive effects on TNB was found on chromosomes 1, 6, 10 and 14 using haplotypes. Using haplotypes from individuals genotyped only at medium-density or a SNP-by-SNP approach did not detect any lethal recessive effects. No lethal recessive haplotypes or SNPs were detected that had an effect on NBA/TNB.ConclusionsWe show that the use of haplotypes from combining medium-density and imputed low-density genotype data is superior for the identification of lethal recessive variants compared to both a SNP-by-SNP approach and to the use of only medium-density data. We developed a formal statistical framework that provided sufficient power to detect lethal recessive variants in species, which produce large full-sib families, while reducing false positive or type I errors. Applying this framework results in improvements in reproductive performance by purging lethal recessive alleles from a population in a timely and cost-effective manner.

Genetic analysis of fertility traits in Jersey crossbred cows

The present study was carried out to evaluate the genetic and non-genetic factors affecting fertility traits viz., number of service per conception (NSPC), service period (SP) and calving interval (CI) and genetic and phenotypic parameters of these traits in Jersey crossbred cattle, maintained at Eastern Regional Station of ICAR-National Dairy Research Institute, Kalyani, West Bengal over a period of 39 years (1976-2014). The least squares means for the NSPC, SP and CI were 1.73±0.08 inseminations, 156.37±7.47 days and 458.32±9.56 days respectively. The study revealed that all the traits were decreasing significantly with parity number. Season was important in determining service period, whereas period of calving influenced calving interval in this study. NSPC, SP and CI did not differ significantly among different genetic groups; but, half-breds of Jersey and Tharparkar (½ Jersey-½ Tharparkar) showed comparatively lower NSPC, SP and CI than half-breds of Jersey and Red Sindhi and other crosses in this study. The random effect of sire was highly significant on all the fertility traits considered in this study. Heritability estimates for NSPC, SP and CI were 0.08±0.06, 0.18±0.08 and 0.16±0.08 respectively. All the three analyzed traits had close genetic relationships. Low to moderate heritability of reproductive traits indicates slow genetic progress through selection and further improvement in reproductive performance can be made either by better management practices or including large number of polymorphic markers associated with fertility in the population to assist animal selection