Measures Of Reproductive Performance Research Articles

Efficacy of using previously used controlled internal drug release (CIDR) insert on the reproductive performance, hormone profiles and economic measures of sheep.

This study was conducted using 120 multiparous Awassi ewes during the breeding season to compare the effects of using previously used controlled internal drug release (CIDR) on the hormone profiles, reproductive performance and economic measures of ewes. Ewes were randomized to receive one of five previously used CIDR (previously used for 6, 12, 18, 24 or 30days) or the new CIDR as a control for 6days (CIDR6, CIDR12, CIDR18, CIDR24, CIDR30, and CIDR0 [control], respectively). Blood samples were collected on four occasions, at the time of CIDR insertion, after 3days of insertion, and at the time of withdrawal and insemination. Serum estradiol (E2) and progesterone (P4) concentrations were measured. Timed insemination was performed 48hr post-CIDR withdrawal. Pregnancy was diagnosed by ultrasonography 23days after insemination and confirmed on day 35. The heat detection rate was significantly (p<0.05) higher in the CIDR0 and CIDR6 groups than in the CIDR18 and CIDR30 groups. The total pregnancy rate and fecundity were significantly (p<0.05) higher in the CIDR6 group than in other groups. P4 level was significantly (p<0.05) higher in the CIDR0 group than in the CIDR30 group at the time of removal. At each time point, the E2 level was significantly (p<0.05) higher in the CIDR6 group than at the other groups. The total variable cost, total cost, return and net profit were higher in the CIDR6 and CIDR0 groups than in the other groups. In conclusion, although previously used CIDRs are efficient at synchronizing oestrus in ewes, the duration of previously usage significantly affected the reproductive parameters and economic profit. CIDRs previously used for 6days and new CIDRs provided the highest fertility and fecundity rates, besides return and net profit. Economically, it is not advisable to use CIDRs that previously used for 12days or more.

Effects on post-fresh period milk production and fertility as a result of prior niacin supplementation of dairy cows during their fresh period

If cows successfully transition the immediate post-partum (i.e., fresh) period, then it is likely they had a limited negative energy balance and avoided metabolic disease. Our objective was to determine if modulating fat metabolism during the fresh period, by feeding ruminally protected niacin (RPNi), had carry-over effects after cessation of its feeding on subsequent milk production and fertility of high producing Holstein cows. Multiparous Holstein cows (701) which had been fed one of four RPNi levels (i.e., 0, 3.5, 7, 14 g/d of nicotinic acid (NA) through 21 ± 3.9 days in milk (DIM), were followed through 150 DIM after they moved from their RPNi treatment fresh pen to common ‘high cow’ pens (i.e., early lactation high producing multiparity cows) where they were not fed RPNi. At their first milk sampling in the high pen (i.e., 48 ± 8.0 DIM), milk and milk fat yields of cows previously fed RPNi 3.5, which had been the highest of all treatment groups while in the fresh pen, slumped to become the lowest yields (P = 0.04 and 0.05, respectively). In contrast, milk and milk fat yields of cows previously fed RPNi 14, which had been lowest of all treatment groups while in the fresh period, increased (P = 0.04, 0.05, respectively) to become the highest yields. Over the next ∼60 DIM, milk and milk component yields of cows from all fresh period treatments converged. Body condition score (BCS) of cows fed 3.5 and 7 g/d NA in the fresh period decreased to the greatest extent (P = 0.01) in early lactation but, by 138 DIM, fresh period RPNi 3.5 cows had gained 0.18 BCS units, while cows previously fed 14 g/d of RPNi had lost 0.23 BCS units. No fresh period RPNi treatment impacted any measure of reproductive performance through 150 DIM, but cessation of RPNi feeding when cows moved to high pens caused immediate changes in performance which differed relative to previous RPNi treatment.

Components of the covariances between reproductive performance traits and milk protein concentration and milk yield in dairy cows

Reproductive performance in dairy cows can be improved through genetic selection and herd management. Milk protein concentration is strongly associated with various measures of reproductive performance, but the relative importance of genetic and environmental components of these associations have not been defined. The primary objective of this study was to estimate the magnitudes of correlations and covariances between 9 reproductive performance traits in dairy cows and each of milk protein concentration and milk yield at 4 levels: genetic, permanent environmental effects of cow, herd-year-season, and residual levels. A retrospective single cohort study was conducted using data collected from seasonally and split calving dairy herds. We used animal models to partition covariances for the relationships between 9 fertility traits and each of milk protein concentration and milk yield at lactation level, with up to 80,203 lactations from 27,244 cows that were 780 herd-year-seasons in 65 herds. For the fertility traits, of the explained covariance with milk protein concentration, between 33 and 79% (median 53%) was genetic and 21 to 67% (median 47%) was nongenetic. We concluded that research should be conducted to identify management strategies that capture the nongenetic components of relationships between milk protein concentration and reproductive performance. Genetic correlations with milk protein concentration were generally similar to genetic correlations with milk yield, but the correlation with milk protein concentration was closer (i.e., the absolute value of the correlation coefficient was nearer to 1) for pregnant by wk 6, a key trait for seasonally and split calving dairy herds (correlation coefficient ± standard error = 0.28 ± 0.05 and -0.17 ± 0.07 for milk protein concentration and milk yield, respectively). As the associations also have substantial genetic components, it is possible that reliabilities of estimated breeding values for fertility may be improved by including milk protein concentration in multitrait genetic evaluation models for fertility traits. From our preliminary analyses, reliabilities were only slightly higher when pregnancy by wk 6 of the breeding period was analyzed with milk protein concentration rather than alone or with milk yield, but further research should be considered to assess this question. Importantly, the benefits of these strong relationships can only be fully harnessed through joint use of both management strategies and genetic strategies.

Effect of Continuous Trio Breeding Compared with Continuous Pair Breeding in ‘Shoebox’ Caging on Measures of Reproductive Performance in Estrogen Receptor Knockout Mice

Some performance standards for continuous trio breeding in 'shoebox' cages for inbred stocks and outbred strains ofmice challenge the minimum floor space recommendations in the 8th edition of the Guide for the Care and Use of LaboratoryAnimals. In our study, we evaluated whether continuous trio breeding could be successfully applied to a breeding colonyof genetically engineered mice housed in shoebox cages with a floor area of 67.6 in2. Mice heterozygous for genetically engineered mutations to estrogen receptors and their wildtype counterparts were continuously bred as trios or pairs. Confounding environmental factors were controlled through standardized husbandry practices and husbandry, and all mice were bred simultaneously to control for temporal factors. Several measures of reproductive performance-including number of littersper female, production index, interlitter interval, litter size at birth, litter size at weaning, weaning rate, and body weight of pups at weaning- were evaluated over approximately 6 mo. Regardless of genotype, interlitter interval, litter size at birth, and litter size at weaning were significantly lower for trio-bred mice than for pair-bred mice. In addition, significant interactions emerged between genotype and breeding strategy for these reproductive measures. Furthermore, significant differencesbetween genotypes occurred for interlitter interval and weaning rate, regardless of breeding strategy. Underlying mechanismsto account for effects of genotype on interlitter interval and the interaction of genotype with breeding strategy were unclearbut may reflect effects of overcrowding and reproductive suppression.

Leg Loss and Fitness in Female Green Lynx SpidersPeucetia viridans(Araneae: Oxyopidae)

The relationship between the extent of leg loss and female fitness was investigated in the green lynx spider Peucetia viridans (Hentz, 1832). Adult females and their egg sacs were collected at nine sites in southern California and three measures of bodily characteristics (carapace width, weight, residual index) and three measures of reproductive performance (egg sac weight, egg number, mean sac weight per young) were determined for each spider. Of the 344 spiders sampled, 17.1% were missing one or more legs, with the frequency of leg loss showing no significant differences with respect to the eight limb positions or the four limb pairs among spiders missing one leg. While female size did not differ among leg-loss groups, females which were intact or which had lost one leg were generally heavier and in better body condition than females which had lost two or three legs. Such eight- and seven-legged females also produced heavier egg sacs and more eggs than six-legged females. These findings do not support Guffey's (1999) prediction that female arachnids which lose two legs experience minimal costs, but they are consistent with Brueseke et al. (2001)'s suggestion that reproductive output might be reduced for female spiders which have lost legs. Why females missing three or more legs did not exhibit a comparable, if not more severe, reduction in egg sac weight and egg number than six-legged females is unknown, though it may be related to the small size of this group (8) and peculiarities of the few spiders in it.

Metritis vaccination in Holstein dairy heifers using a herd-specific multivalent vaccine – Effects on uterine health and fertility in first lactation

In cattle, acute puerperal metritis (APM) compromises animal welfare and has an economic impact to the farmer because of the detrimental effects on reproductive performance, milk production, and survivability. The aim of this randomized clinical study was to investigate the effects of a prepartum immunization using a herd-specific multivalent vaccine on incidence of APM, prevalence of clinical endometritis (CE), and selected measures of reproductive performance in primiparous Holstein cows. Pregnant nulliparous cows (230±4days of gestation) assigned to the vaccinated group (VG; n=142) received subcutaneously 5.0mL of a multivalent herd-specific vaccine containing inactivated whole bacterial cells of Trueperella pyogenes, Escherichia coli, Streptococcus uberis, Bacteroides species, and Peptostreptococcus species obtained from uterine swabs of primiparous cows suffering from APM at the time of enrolment and three weeks later. Heifers allocated to the control group (Co; n=144) remained unvaccinated. Rectal temperature in the first 10days in milk (DIM) did not differ between treatments, and no interaction between treatment and day was observed (interaction treatment*day: p=0.623). Incidence of APM (VG, 46.0%, Co, 48.9%, p=0.588), number of antibiotic doses per cow to treat APM (VG, 0.63±0.81, Co, 0.64±0.75, p=0.496), prevalence of CE at 35 DIM (VG, 24.6%, Co, 19.3%, p=0.350), first service pregnancy per artificial insemination (VG, 40.3%, Co, 45.5%, p=0.541), number of inseminations until 150 DIM (VG, 2.0±1.4, Co, 1.9±1.3, p=0.749), interval from calving to first service (median days, VG, 52, Co, 52, p=0.915), and interval from calving to pregnancy (median days, VG, 90, Co, 83, p=0.419) did not differ between VG and Co. Treatment did not affect activity of aspartate aminotransferase (AST) and creatine kinase (CK) or concentrations of beta-hydroxybutyrate (BHB) and haptoglobin in serum samples collected at 5 DIM. Furthermore, treatment did not influence yields of milk, fat or protein in the first 100 DIM. Moreover, no signs that vaccination provided an attenuation of severity of the APM cases were detected as the course of rectal body temperature and values of AST, CK, BHB, and haptoglobin were not influenced by treatment within the group of cows with diagnosed APM. Use of this herd-specific multivalent vaccine designed to reduce metritis was not efficacious at reducing the risk of uterine disease or influencing production and reproduction in dairy cows.

Research trends in outdoor pig production - A review.

Since the industrialization of swine production in the late 1900s, swine farms in the United States, as well as in Europe, have largely become consolidated. Pig farms became larger in size but fewer in number, with 91% of market pigs being produced by large operations with 5,000 or more pigs on-site in the US, and only 3% of the total utilized agricultural land representing organic farming. Such change in the market made it difficult for small farmers to stay competitive, forcing them to find alternative ways to reduce the cost of production and increase profit using the outdoor production system. In contrast to the indoor confinement system, outdoor production system uses pasture-based units and/or deep-bedded hoop structures that promote animal welfare and environmental sustainability with a lower capital investment. In accord with the growing concern for animal and environmental welfare and food safety by the consumers, small farmers practicing an outdoor production system are seeing increased opportunities for marketing their products in the pork niche market. Unlike the general belief that the reproductive and growth performance measures of the outdoor sows and piglets are poorer in comparison with the animals reared indoors, studies showed that there was no significant difference in the performance measures, and some traits were even better in outdoor animals. Improved reproductive and production traits can increase the sustainability of outdoor farming. Present study reviewed the recent studies comparing the performance measures, meat quality and health of indoor and outdoor animals, as well as the efforts to improve the outdoor production system through changes in management such as hut types and breed of animals.

Evaluating the reliability of species distribution models with an indirect measure of bird reproductive performance

Measures of fitness such as reproductive performance are considered reliable indicators of habitat quality for a species. Such measures are, however, only available in a restricted number of sites, which prevents them from being used to quantify habitat quality across landscapes or regions. Alternatively, species presence records can be used along with environmental variables to build models that predict the distribution of species across larger spatial extents. Model predictions are often used for management purposes as they are assumed to describe the quality of the habitats to support a species. Yet, given that species are often present both in optimal and suboptimal areas, the use of data collected during the breeding season to build these models may potentially result in misleading predictions of habitat quality for the reproduction of the species, with potentially significant conservation consequences. In this study we analysed the relationship between fitness parameters informing on habitat quality for reproduction and predictions of species distribution models at multiple spatial scales using two independent sets of data. For 19 passerine bird species, we compared an indirect measure of reproductive performance (ratio of juveniles‐to‐adults) – obtained from Constant Effort Sites (CES) mist‐netting data in Catalonia – with the predictions of models based on bird presence records collected during the Catalan Breeding Bird Atlas (CBBA). A positive relationship between the predictions derived from species distribution models and the reproductive performance of the species was found for almost half of the species at one or more spatial scales. This result suggests that species distribution models may help to predict habitat quality for some species over some extents. However, caution is needed as this is not consistent for all species at all scales. Further work based on species‐ and scale‐specific approaches is now required to understand in which situations species distribution models provide predictions that are in line with reproductive performance.

Milk protein concentration, estimated breeding value for fertility, and reproductive performance in lactating dairy cows

Milk protein concentration in dairy cows has been positively associated with a range of measures of reproductive performance, and genetic factors affecting both milk protein concentration and reproductive performance may contribute to the observed phenotypic associations. It was of interest to assess whether these beneficial phenotypic associations are accounted for or interact with the effects of estimated breeding values for fertility. The effects of a multitrait estimated breeding value for fertility [the Australian breeding value for daughter fertility (ABV fertility)] on reproductive performance were also of interest. Interactions of milk protein concentration and ABV fertility with the interval from calving date to the start of the herd's seasonally concentrated breeding period were also assessed. A retrospective single cohort study was conducted using data collected from 74 Australian seasonally and split calving dairy herds. Associations between milk protein concentration, ABV fertility, and reproductive performance in Holstein cows were assessed using random effects logistic regression. Between 52,438 and 61,939 lactations were used for analyses of 4 reproductive performance measures. Milk protein concentration was strongly and positively associated with reproductive performance in dairy cows, and this effect was not accounted for by the effects of ABV fertility. Increases in ABV fertility had important additional beneficial effects on the probability of pregnancy by wk 6 and 21 of the herd's breeding period. For cows calved before the start of the breeding period, the effects of increases in both milk protein concentration and ABV fertility were beneficial regardless of their interval from calving to the start of the breeding period. These findings demonstrate the potential for increasing reproductive performance through identifying the causes of the association between milk protein concentration and reproductive performance and then devising management strategies to capitalize on them. Research should be conducted to understand the component of the relationship not captured by ABV fertility.

Antibiotic treatment of metritis in dairy cows—A meta-analysis

The objective of this meta-analysis was to assess the efficacy of the treatment of bovine metritis with common antibiotic and nonantibiotic treatment options. Acute puerperal metritis, a systemic and potentially painful illness with rectal temperature >39.5°C and signs of toxemia due to an infection of the uterus, occurs within 21 d after parturition. Because of the infectious nature, antibiotics are considered beneficial for the treatment of acute puerperal metritis. Each use of an antimicrobial drug, however, is associated with selective pressure for eventual emergence of resistant bacteria. The 23 trials evaluated in the course of a previously conducted systematic review were the basis for meta-analytic investigations. Selected trials were screened regarding their eligibility for the following investigations: (1) comparison of different antibiotic treatments with respect to metritis prevalence at time of re-examination, (2) efficacy of ceftiofur treatment with respect to metritis prevalence at time of re-examination, (3) comparison of efficacy of antibiotic versus nonantibiotic drugs with respect to metritis prevalence at time of re-examination, and (4) equivalence assessment of treatment effects on reproductive performance measures. Where at least 3 trials had investigated the same outcome variable and met the inclusion criteria (inclusion of a control or reference group diagnosed with metritis; reporting means and standard deviation in case of continuous data), meta-analytic investigations were carried out. Due to a shortage of comparable studies, we could not conduct investigations (1) and (3). Ceftiofur treatment of 828 metritic cows was associated with a decrease in the prevalence of metritis following treatment in comparison to 804 untreated cows. In conclusion, meta-analytic investigations uncovered a need for more high-quality studies. Furthermore, a positive effect of the most commonly used antibiotic drug, ceftiofur, for the treatment of bovine metritis could be shown. A comparison with other antibiotic or nonantibiotic treatment options could not be made.

Associations between milk protein concentration at various stages of lactation and reproductive performance in dairy cows

Milk protein concentration has been positively associated with a range of measures of reproductive performance in dairy cows. These beneficial associations are most likely due to factors affecting both milk protein concentration and reproductive performance possibly being mediated, in part, by energy balance during early lactation. However, it is likely that factors other than energy balance are also involved in these relationships. A retrospective single cohort study was conducted using subsets of data collected from 74 dairy herds with seasonal or split calving patterns. Associations between milk protein concentration at various stages of lactation and reproductive performance in Holstein dairy cows were assessed using random effects logistic regression and survival analysis with milk protein concentration during the cow's breeding period fitted as a time-varying covariate. The beneficial associations between milk protein concentration and each of the 4 selected indices for measuring reproductive performance were evident when milk protein concentration was derived for each 30-d period from calving up to 300d in milk. For the first 150d of lactation the adjusted odds ratios were highest from 31 to 60d and only slightly lower for all periods up to 150d of lactation. Estimated associations for 31 to 60d were stronger than for 0 to 30d. In addition, milk protein concentration during a cow's breeding period was positively associated with the subsequent daily hazard of conception, even after adjusting for milk protein concentration in the cow's first or second month of lactation. Milk protein concentrations from 0 to 30d of lactation were less closely correlated with concentrations measured at subsequent 30-d intervals; correlations were closer between other periods in lactation. These results indicate that the association between milk protein concentration and reproductive performance is partly due to factors other than the extent of negative energy balance in early lactation. However, it is possible that energy balance accounts for some of the relationship as the magnitude and direction of energy balance can vary within and between cows throughout lactation. Factors determining milk protein concentration during the first 30d of lactation are not identical to the causes of milk protein concentration later in lactation, and some of the latter causes of milk protein concentration may be more closely related to the underlying mechanisms contributing to the milk protein concentration-reproductive performance relationship. Milk protein concentrations from a single test day from any day of lactation predict subpopulations of cows with differing average reproductive performance; milk protein concentrations measured after 30d of lactation are more useful than concentrations measured in the first 30d for identifying these subpopulations. Further research is required to identify the causes of these associations.

Associations between milk protein concentration, milk yield, and reproductive performance in dairy cows.

Milk protein concentration in dairy cows has been positively associated with a range of measures of reproductive performance. It was possible that these associations were due to confounding by milk volume. A retrospective single cohort study was conducted using data collected from 74 dairy herds with seasonal or split calving patterns. Associations between milk protein concentration and reproductive performance in Holstein dairy cows were assessed using random effects logistic regression. The key finding from this study was that the associations between milk protein concentration in early lactation and reproductive performance were not due to confounding by milk yield. Associations between milk protein concentration and reproductive performance were weaker at higher early lactation milk yields, but positive associations were evident at all milk volumes assessed. The second major finding was that increases in milk yield were associated with improved proportions of cows pregnant by wk 6 and 21 at low to moderate milk protein concentrations but with decreases in these reproductive measures at high milk protein concentrations. Thus, no simple relationship is present between milk yield and reproductive performance; effects of milk yield depend on milk protein concentration. These results indicate that mechanisms causing the associations between milk protein concentration and reproductive performance may be linked to milk yield but these mechanisms operate over a wide range of milk yields (<2,000 to ≥5,000kg in the first 120d of lactation). Further research is required to identify the causes of these associations.

Survey of reproduction management on Canadian dairy farms.

The objectives of this study were to (1) quantify current reproduction management practices, and (2) assess the association between these practices and herd reproductive performance on dairy farms in Canada. A bilingual survey was developed, validated, and administered from March to May 2014 to collect general and reproduction management and performance measures [annual 21-d pregnancy rate (PR), 21-d insemination rate (IR), and conception risk (CR)]. Associations between management practices and reproductive performance measures were tested using linear regression models. A total of 832 questionnaires were completed online and by mail, representing a response rate of 9%. On average, farms had 77 lactating cows (median=50) and 13 dry cows (median=10), and Holstein was the most common breed (92% of herds). Lactating cow housing was tiestall on 61% of the farms, freestall on 37%, and bedded pack on 2%. The average voluntary waiting period was 58 d in milk (DIM). The main reproduction management practice per farm was defined as the means employed for >50% of inseminations. Farms reported their main reproduction management practice for first and subsequent inseminations, respectively, as visual estrus detection (51 and 44% of herds), timed AI (21 and 23% of herds), automated activity monitoring (AAM; 10 and 10% of herds), other management practice (bulls; 2 and 2% of herds), and a combination of management practices (16 and 21% of herds). On farms using visual estrus detection, cows were observed for signs of estrus on average 3.5 times per day, for an average total of 36 min/d. The most common use of reproductive hormones was to synchronize ovulation using Ovsynch (58% of the farms). Average PR, IR, and CR were 17.6, 44.1, and 40.5%, respectively. In linear regression analyses adjusted for confounders, pregnancy rate was significantly associated with geographic region, housing (tiestall: PR=15.4%, freestall: PR=17.6%), herd size (<50 lactating cows: PR=16.2%, 50-100 cows: PR=16.5%, >100 cows: PR=17.8%), voluntary waiting period (≤60 DIM: PR=17.6%, >60 DIM: PR=15.9%), and frequency of insemination per day (once daily: PR=16.6%, twice or more daily: PR=18.1%). The main reproduction management practice at first and subsequent inseminations was divergently associated with IR and CR, but not with PR (visual heat detection: PR=17.4%, timed AI: PR=18.4%, AAM: PR=17.1%, combined practices: PR=18.2%).

Evaluation of 2 sugarcane molasses feeding strategies on measures of growth and reproductive performance of replacement beef heifers

ABSTRACT Our objectives were to compare the effects of 2 sugarcane molasses feeding strategies on growth (Exp. 1 and 2), reproductive performance (Exp. 1), and forage intake (Exp. 2) of replacement beef heifers. In Exp. 1 and 2, treatments consisted of cottonseed meal manually mixed with molasses in a slurry form (SLU), or cottonseed meal and molasses provided in separate bunks (SEP). In Exp. 1, 48 Brangus-crossbred heifers (BW = 236 ± 4 kg; age = 335 ± 5 d) were randomly assigned to 1 of 12 bahiagrass pastures (4 heifers per pasture; 6 pastures per treatment). Each pasture received 31.8 kg of molasses and 6.4 kg of cottonseed meal (as fed) twice weekly from d 0 to 70. In Exp. 2, Braford heifers were randomly assigned into 1 of 16 drylot pens to evaluate the daily hay DMI of heifers offered SEP or SLU supplementation twice weekly from d 0 to 21. Effects of treatment and treatment × day were not detected for BW and ADG of heifers in Exp. 1 and 2 ( P ≥ 0.27). In Exp. 1, overall pregnancy rates were similar ( P = 0.55), but puberty achievement tended to be greater for SLU versus SEP heifers ( P = 0.10). In Exp. 2, G:F and hay DMI did not differ between treatments ( P ≥ 0.21). Therefore, cottonseed meal and sugarcane molasses can be offered separately rather than in a slurry form without affecting growth, forage intake, and reproductive performance of grazing replacement beef heifers during breeding season.

A cross-sectional survey of population demographics, the prevalence of major disease conditions and reason-specific proportional mortality of domestic cattle in the Kingdom of Bhutan

We describe the population demographics, rudimentary measures of reproductive performance, the prevalence of major disease conditions and reason-specific proportional mortality for cattle owned by villagers in 16 dzongkhags (districts) in Bhutan based on the findings of a cross-sectional study carried out between March 2012 and May 2014. The animal health issues that were of concern for livestock owners are also identified. Study households were selected using a stratified, two-stage cluster design. Districts (dzongkhags) formed the strata. Villages within dzongkhags were the first sampling stage and households within villages the second sampling stage. All cattle within each selected household comprised the study population.Questionnaires were collected from 409 households with 1480 standing cattle. A total of 71.0% (95% CI 67.9%–74.1%) of the standing cattle population were female and the median age of cattle was 5 years (Q25 3 years; Q75 7 years). Exotic breeds of cattle (Jerseys, Brown Swiss, and their crosses) comprised 41.4% of the cattle population with local breeds making up the remainder. Although exotic breeds of cattle had a significantly lower age at first calving (median 4 years) compared to local breeds (median 4.8 years) there was no significant difference in the number of calving events per cow for the two breed groups. Diarrhoea was the most prevalent disease condition with 2.8 (95% CI 1.5–4.6) cases per 100 animals followed by bovine enzootic haematuria with 1.9 (95% CI 1.0–3.3) cases per 100 animals. The most frequently cited cause of death was misadventure (proportional mortality 26.2%, 95% CI 15.7%–39.2%) followed by old age (17.8%, 95% CI 9.5%–29.4%). A lack of access to adequate fodder and pasture was the animal health issue that was cited by interviewees most frequently.We provide no evidence that exotic breeds of cattle have superior reproductive performance compared with local breeds. The major cattle health concern cited by interviewees, lack of access to fodder, is likely to contribute to suboptimal productivity and the relatively high incidence of bovine enzootic haematuria in this population. We propose that a prospective cohort study of Bhutanese cattle is warranted to more fully elucidate factors affecting the productivity and longevity of cattle in Bhutan.

Application of transcriptomic analyses to reproductive studies in contemporary commercial sows

Genetic selection in sows has substantially increased the total number of pigs born, but there has been an associated decrease in litter birth weight. Furthermore, irrespective of the total number of pigs born, a repeatable low litter birth weight phenotype has evolved in a subpopulation of mature sows, in which a high ovulation rate drives extremes of intrauterine crowding in early gestation and limits placental development: placental development continues to be compromised in later gestation and is associated with intrauterine growth restriction and a low litter birth weight. Furthermore, although contemporary commercial sows are increasingly resilient to the challenges of lactational catabolism in terms of the traditional measures of reproductive performance, gender-specific effects on early embryonic development of the subsequent litter are apparent and are likely linked to effects of sow catabolism on folliculogenesis and oocyte maturation. Recent transcriptomic studies that have helped elucidate some of the regulatory mechanisms mediating the evolving changes in the reproductive biology of contemporary commercial sows are summarized in the present review. However, the lack of clearly differentiated reproductive phenotypes among commercial sow populations is a problem for ongoing studies. Access to an unselected “wild-type” population with which to make comparisons, or the application of more standardized experimental approaches to mechanistic studies, may help advance the field of sow reproductive biology.

Pappa2 deletion in mice affects male but not female fertility.

BackgroundRecent studies have found associations between the gene encoding pregnancy associated plasma protein-A2 (PAPP-A2), a protease of insulin-like growth factor binding protein -5 (IGFBP-5), and measures of female reproductive performance in cattle. The purpose of the present study was to test the effects of Pappa2 deletion on reproduction in mice.FindingsWe measured the fertility and offspring growth of Pappa2 deletion females, and also performed reciprocal matings (i.e., deletion males mated to control females) to control for the effects of offspring genotype. Ovarian and testicular IGFBP-5 levels were measured by Western blotting. As expected, deletion of Pappa2 increased ovarian IGFBP-5 levels. However, Pappa2 deletion in females had no effect on the interval between pairing and the birth of the first litter, the interval between the births of the first and second litters, or litter size. Offspring weight was lower in the offspring of Pappa2 deletion females, but effects of similar magnitude were observed in the offspring of Pappa2 deletion males, suggesting that the effects were due to heterozygosity for the deletion in the offspring. Pappa2 deletion in males had no effect on litter size or the interval between pairing and the birth of the first litter. However, the interval between the births of the first and second litters was significantly longer in deletion males.ConclusionsPappa2 deletion had no effect on female reproductive performance. In contrast, Pappa2 deletion had subtle effects on male fertility, although the underlying mechanism remains to be elucidated.

Experimental reduction of haematocrit affects reproductive performance in European starlings

Summary Given the function of haemoglobin and observed increases in haematocrit during periods of increased energetic demands, haematocrit and haemoglobin are assumed to be related to aerobic capacity. Reductions in haematocrit and haemoglobin during reproduction are similar in magnitude to increases associated with aerobically demanding activities, and therefore, we sought to investigate whether these reductions in haematology have consequences for reproductive performance. We analysed associations between natural variation in haematology in free‐living European starlings (Sturnus vulgaris) and reproductive performance. To test whether transient reductions in haematology during different stages of reproduction (egg production and late incubation/early chick rearing) affected measures of reproductive performance, we also manipulated haematology using phenylhydrazine (PHZ), which lyses red blood cells. To investigate effects of reductions of haematology during egg‐laying, we treated females with PHZ or saline (control) upon completion of their unmanipulated first clutch and removed eggs to induce the production and rearing of a replacement clutch. To investigate effects of reductions of haematology during chick rearing, we treated females during incubation of the unmanipulated first clutch and then monitored the subsequent hatching and rearing of the clutch. Individuals with higher haematocrit and haemoglobin initiated nesting earlier. Furthermore, higher haemoglobin levels during incubation were associated with a greater number of chicks fledged. PHZ treatment prior to egg production resulted in a significant delay in the laying of replacement clutches, but had no effect on provisioning rate or the size or number of chicks fledged. PHZ treatment during incubation and early chick rearing resulted in decreased hatchling mass in all years and a decrease in the size and number of fledglings in one of 2 years. The year that the effect of PHZ was observed appeared to be a particularly difficult year, as hatchling mass, brood size at hatching and at fledging were low among control females compared to other years. Our results suggest that a reduction in haematology during reproduction can be functionally significant, but that these costs are context‐dependent.

Effects of space allocation and parity on selected physiological and behavioural measures of well-being and reproductive performance in group-housed gestating sows

The aim of this study was to evaluate the effects of parity and space allowance on selected measures indicative of welfare, and on reproductive parameters, in group-housed sows. Selected animals were at first parity or parity three or greater, and were housed with allocated space allowances per pig of 1.4 or 2.8m2. Welfare outcome measures included: injury and lameness scores, plasma cortisol levels, neutrophil:lymphocyte ratios and reproductive performance. These values were recorded at a range of timepoints in the first 24h after mixing, and at 28 days after the mixing event. In general there were few significant effects of space allowance and parity level on the measured outcomes. However, improved reproduction, as evidenced by increased litter size and born alive figures, was seen as a result of increased space allowance in older animals. A contrary response was observed in gilts. Cortisol responses also indicated that there was a rapid habituation to the stress of mixing with levels returning to baseline within 24h. Cortisol levels remained low in older animals but unexpectedly showed a peak at 28 days in gilts. It is postulated that this may have arisen as a result of handling events associated with pregnancy testing.Our results suggest that at least at the chosen stocking densities, parity and space allocation have minimal effect on a number of commonly-used welfare measures.

Roles of phenotypic and genetic characteristics in the social mating pattern of Silver-throated Tits (Aegithalos glaucogularis)

Choice of mating partners may affect fitness. Both phenotypic and genetic traits have been shown to play roles in the mating processes of animals. We investigated the roles of phenotypic and genetic characteristics in the patterns of social mating in the Silver-throated Tit (Aegithalos glaucogularis), a sexually monochromatic species that exhibits sexual size dimorphism, rarely sings, does not occupy territories, and has a relative low level of extrapair paternity. To explore the role of phenotype traits, we tested for assortative mating based on the sizes of seven morphological traits. To explore the role of genetic traits, we tested for assortative mating with respect to genetic heterozygosity (the heterozygous mate hypothesis) and whether birds mated with genetically dissimilar individuals (the compatible mate hypothesis). We found significant correlations between paired individuals for bill length and body length, indicating possible assortative mating based on these two traits. In contrast, genetic heterozygosity was not correlated between paired individuals, and the mean relatedness of the mates was not significantly different from that of randomly mated individuals, which do not support the idea that Silver-throated Tits assortatively mate with heterozygous individuals or choose genetically dissimilar mates. Also, individual heterozygosity was not reflected in the measured morphological traits, as no correlation was detected. Neither the individual heterozygosity nor the relatedness between mates was correlated with reproductive performance measures, including clutch size, brood size, and number of fledglings. However, we found that clutch size increased with female body length, which could explain the benefit to males of mating with larger females. Taken together, while our current data failed to provide evidence for an effect of genetic characteristics on the social mating pattern of Silver-throated Tits, the results suggest that phenotypic traits are likely associated with their mating pattern.