Incidence and timing of pregnancy loss following timed artificial insemination or timed embryo transfer with a fresh or frozen in vitro-produced embryo.

The aim of this study was to characterize the incidence and timing of pregnancy loss from service event (timed artificial insemination or timed embryo transfer) to parturition. Lactating Holstein-Friesian cows were randomly assigned to receive either artificial insemination (AI, n = 243) or embryo transfer (ET, n = 863) with a fresh or frozen in vitro-produced blastocyst derived from oocytes collected from the ovaries of elite dairy donors (n = 14 Holstein Friesian and n = 8 Jersey) and elite beef donors (n = 21 Angus) using transvaginal ovum pick-up. In addition, oocytes were collected from the ovaries of beef heifers of known pedigree following slaughter at a commercial abattoir (n = 119). Blood samples were collected on d 7 from all cows to determine progesterone concentration and from subsets of cows on d 18 (n = 524) and d 25 (n = 378) to determine mRNA abundance of interferon-stimulated gene-15 and pregnancy-specific protein B concentration, respectively, to provide an early pregnancy diagnosis. Transrectal ultrasonography was conducted to determine pregnancy status on d 32, d 62 and d 125 after synchronized ovulation. Parturition date was recorded for all cows that reached a term delivery. The predicted probability of pregnancy (%) varied at each time point (d7, 18, 25, 32, 62, 125, parturition) depending on treatment (AI: 77.0, 60.2, 52.3, 48.8, 47.0, 44.6, 44.0; fresh ET: 100.0, 69.5, 60.3, 56.1, 48.4, 46.8, 45.5; frozen ET: 100.0, 61.7, 52.2, 41.6, 32.9, 31.8, 30.2). Irrespective of treatment, the largest proportion of pregnancy loss occurred in the period from service event (AI on d 0 or ET on d 7) to d 18, with minimal loss occurring between d 62 and parturition (AI: 1.8%, fresh ET: 1.9%, frozen ET: 3.5%). Treatment differences in the predicted probability of pregnancy per service event were detected between fresh ET vs frozen ET on d 32 and both AI and fresh ET vs frozen ET on d 62, 125 and at parturition. There was greater probability of pregnancy loss between d 32 and 62 following ET (Fresh: 11.3%, Frozen: 18.0%) than AI (4.0%). The percentage of cows that calved following transfer of a fresh embryo (45.5%) was similar to AI (44.0%), but less when a frozen embryo was transferred (30.2%). In conclusion, AI and fresh ET led to a greater probability of a cow becoming pregnant and maintaining the pregnancy to term than frozen ET. Cows that were still pregnant on d 62 had a very strong likelihood of maintaining the pregnancy to full-term parturition, irrespective of treatment. Further work is required to improve the likelihood of pregnancy establishment and reduce embryonic and fetal mortality following transfer of a cryopreserved in vitro-produced embryo.

Impact of different mating ratios of broiler breeder on reproductive performance during post moult phase.

Studies comparing mating ratio after forced molting are important for improving the efficiency of broiler breeder flocks. This study examined the effect of mating ratios on Egg production, chick weight, fertility, hatchability and embryonic mortality rate in Arbor Acres Plus broiler breeders post-moult phase. A total of 195 birds (62 weeks old), consisting of 15 cocks and 180 hens were randomly allocated with uniform body weight in a Completely Randomized Design into three groups based on the mating ratio (cock to hen). The groups included ratios of 1:10, 1:12, and 1:14, with each group replicated 5 times. Eggs were collected twice a day, and stored for 7 days at room temperature before placing them in the incubator. Results showed that mating ratios 1:10 and 1:12 had a positive effect on fertility rate and total hatchability compared to the 1:14 ratio. However, mating ratios did not affect laying rate, egg weight, egg mass, chick weight, hatchability of fertile eggs, and embryonic mortality rate. In conclusion, to reduce the cost of raising and caring cocks, a mating ratio of one cock to every twelve hens can be used for broiler breeders after forced molting to obtain the best fertility and hatching results.

Biological Traits and Comprehensive Genomic Analysis of Novel Enterococcus faecalis Bacteriophage EFP6.

Enterococcus faecalis is a prevalent opportunistic pathogen associated with chicken embryonic and neonatal chick mortality, posing a significant challenge in poultry farming. In the current study, E. faecalis strain EF6, isolated from a recent hatchery outbreak, served as the host bacterium for the isolation of a novel phage EFP6, capable of lysing E. faecalis. Transmission electron microscopy revealed a hexagonal head and a short tail, classifying EFP6 as a member of the Autographiviridae family. EFP6 showed sensitivity to ultraviolet radiation and resistance to chloroform. The lytic cycle duration of EFP6 was determined to be 50 min, highlighting its efficacy in host eradication. With an optimal multiplicity of infection of 0.001, EFP6 exhibited a narrow lysis spectrum and strong specificity towards host strains. Additionally, EFP6 demonstrated optimal growth conditions at 40 °C and pH 8.0. Whole genome sequencing unveiled a genome length of 18,147 bp, characterized by a GC concentration of 33.21% and comprising 25 open reading frames. Comparative genomic assessment underscored its collinearity with related phages, notably devoid of lysogenic genes, thus ensuring genetic stability. This in-depth characterization forms the basis for understanding the biological attributes of EFP6 and its potential utilization in phage therapy, offering promising prospects for mitigating E. faecalis-associated poultry infections.

Early prognostic markers to predict unsuccessful pregnancy in dairy cattle.

This study aimed to investigate maternal serum levels of some angiogenic factors and certain proteins in dairy cattle for (1) early prediction of unsuccessful fertilization and (2) early detection of possible pregnancy failures (early EM) after positive insemination Serum samples were collected from the same cattle at three distinct time points: 30 days before artificial insemination (B-AI), on the day of artificial insemination (AI), and 30 days after artificial insemination (A-AI). As a result of the pregnancy examination, the cows were divided into two main groups according to whether they were pregnant. The results showed that leucyl/cystinyl aminopeptidase (LNPEP) concentration was significantly decreased B-AI and Secreted frizzled-related proteins (SFRP-3), Vascular Endothelial Growth Factor (VEGF) and LNPEP levels were significantly decreased on day of AI, while PRL level was increased, and these data have prognostic significance as early indicator of the risk of potentially failed pregnancy. Additionally, a significant decrease in LNPEP, SFRP3, and VEGF levels, along with an increase in PRL levels was also observed in A-AI. These results suggest that these biomarkers can be used as a screening test to monitor the course of pregnancy. There were no significant differences in serum levels of Insulin-Like Growth Factor 2 (IGF-2), Tissue inhibitors of metalloproteinases (TIMP-1), angiopoietin (ANG), Endoglin (ENG), Fibroblast growth factor (FGF), Inhibine-A (INH-A) and Transforming growth factors-ß1 (TGF-ß1) between the evaluated periods neither unsuccessful nor the successful pregnancy groups. This is the first study reporting that the maternal serum levels of LNPEP, SFRP3, VEGF, and PRL have important roles in pregnancy success and may indicate whether insemination outcome will be successful B-AI and predict the risk of unsuccessful pregnancy after AI in dairy cattle. The increase in such studies will allow the development of more specific, practical, and applicable markers.

Hatchery Losses in Flocks of Layer and Broiler Breeders Due to Feed Contamination with Nicarbazin and Narasin: A Case Report.

In the current study, we investigated decreased hatchability and increased embryonic mortality in two farms of layer breeders (flocks A1 and B1) and a farm of broiler breeders (flocks C1 and C2) from Austria, which also presented discoloration of eggshells in 2% of the eggs. After conducting clinical evaluations and the approval that the feed operator was common for flocks A1 and B1, and C1 and C2, it was decided to investigate the feed. Our findings revealed that the feed contained levels of nicarbazin and narasin up to five and 14 times, respectively, above the maximum limits allowed by the European Union for nontarget species. On the other hand, there were no significant abnormalities in vitamin levels, which were also described as the etiology of the noticed abnormalities. Switching to a noncontaminated feed resulted in the clinical signs and production parameters returning to expected ranges. This report emphasizes the significance of considering feed contamination by nicarbazin and narasin as a potential cause of hatchery losses in nontarget species, even in the absence of other clinical signs.

Reporte de caso- Pérdidas en la eclosión de parvadas de reproductoras ponedoras y pollos de engorde debido a la contaminación del alimento con nicarbazina y narasina: Reporte de un caso. En el presente estudio, se investigó la disminución de la incubabilidad y el aumento de la mortalidad embrionaria en dos granjas de reproductoras ponedoras (parvadas A1 y B1) y una granja de reproductoras de pollos de engorde (parvadas C1 y C2) de Austria, que también presentaron decoloración del cascarón en el 2% de los huevos. Luego de realizar evaluaciones clínicas y la aprobación de que el operador de alimento era común para las parvadas A1 y B1, y C1 y C2, se decidió investigar el alimento. Nuestros hallazgos revelaron que el alimento contenía niveles de nicarbazina y narasina de hasta cinco y 14 veces, respectivamente, por encima de los límites máximos permitidos por la Unión Europea para especies no objetivo. Por otro lado, no se observaron anomalías significativas en los niveles de vitaminas, lo que también se describió como la etiología de las anomalías observadas. El cambio a un alimento no contaminado provocó que los signos clínicos y los parámetros de producción regresaran a los rangos esperados. Este informe enfatiza la importancia de considerar la contaminación del alimento por nicarbazina y narasina como una causa potencial de pérdidas en la eclosión de especies no objetivo, incluso en ausencia de otros signos clínicos.

Impact of the Sire on Pregnancy Loss.

For over a century, scientists have attempted to develop techniques to accurately predict the fertility potential of a male's semen sample. In most livestock species, the sire is responsible for multiple pregnancies per year and up to hundreds of thousands of pregnancies if used for artificial insemination. Use of subfertile or infertile sires can have devastating impacts in regard to the reproductive efficiency of a cow herd. Despite the rapid expansion of fertility studies through advancements in molecular, genomic, and computer techniques, our understanding of male fertility is still far from complete. This article will provide an overview of the impact of the sire in pregnancy loss.

Impacts of Diet on Reproductive Performance of Captive American Alligators (Alligator mississippiensis).

Historically, there has been little success with the captive breeding of American alligators (Alligator mississippiensis) for both commercial and conservative purposes. This study, conducted at Golden Ranch in Gheens, LA, between 2016 and 2022, utilized a newly formulated commercial feed and practical dietary supplementation (crawfish waste products) to enhance egg production, fertility, and hatch rates. The primary focus of this study was to compare the outcome of this captive breeding program at Golden Ranch with a program conducted at Rockefeller Refuge (RR) between 1979 and 1984. Notable success was achieved in terms of reproductive performance in comparison to the captive breeding program conducted at Rockefeller Refuge. In this study, 16.1 hatchlings were produced per nest on Golden Ranch from captive breeders. Additionally, when wild nests from Golden Ranch were incubated in the same controlled environmental chambers, they produced an average of 16.3 hatchlings per nest. This comparison emphasizes the similarity in egg production between captive-bred A. mississippiensis and their wild counterparts. The findings of this study suggest that a closed farming system for A. mississippiensis can be established by employing captive breeders derived from artificially incubated wild eggs. Furthermore, American alligators raised in controlled environmental chambers during their initial three years of life demonstrated adaptability to captive conditions and tolerated stocking rates associated with farming conditions and served as breeding stock.

Research Note: Effects of feeding corn naturally contaminated with aflatoxin B1, deoxynivalenol, and zearalenone on reproductive performance of broiler breeders and growth performance of their progeny chicks.

To evaluate the toxic effects of mycotoxin-contaminated corn (MC) on the breeders and their progeny chicks, a total of 480 fifty-wk-old Cobb broiler breeder hens were fed the following dies: 1) a corn-soybean meal diet (Control; containing 70.35% corn), 2) MC substituting for 50% of corn in Control (LM), 3) LM diet plus 2 g/kg 1 mycotoxin sequestrant, Toxy-Nil Plus (TNP) (LMT2.0), 4) MC substituting for 100% of corn in Control (HM), 5) HM diet plus 2 g/kg TN (HMT2.0), and 6) HM diet plus 2.5 g/kg TNP (HMT2.5). The MC contained 69.25 µg aflatoxin B1 (AFB1)/kg, 4,875 µg deoxynivalenol (DON)/kg, and 2,262 µg zearalenone (ZEN)/kg. At wk 4 after MC inclusion, all eggs laid were used for hatch, and all progeny chicks were fed the same mycotoxin-untreated diet for 14 d. Dietary MC inclusion decreased the hatchability of set eggs and increased embryo mortality during d 18 to 21.5. The TNP addition increased these aforementioned indices in MC-included diets. Maternal HM treatment decreased the BW of progeny chicks at age of 14 d and BWG of progeny chicks during d 1 to 14, whereas maternal LM treatment did not affect these indices. In parallel, maternal HM treatment decreased the concentrations of serum IgA, IgG, and lysozyme in the progeny chicks on d 14, but maternal LM treatment did not affect these indices. Overall, maternal dietary TNP treatments increased the growth of progeny chicks and had a trend to increase the concentrations of serum IgA and IgG on d 14 compared to maternal MC treatments. It was concluded that the feeding of relative high ratio of corn contaminated with low level of AFB1, DON, and ZEN negatively affected the reproductive performance of breeders and the growth performance of their progeny chicks, and TNP addition alleviated these toxic effects.

Administration of GnRH at day 20 of AI and embryonic losses in synchronized crossbred buffalo.

Introduction: Following the application of different artificial insemination and synchronization protocols, the synchronized buffaloes had a higher incidence of early embryonic or fetal death, thus impairing reproductive performance. Therefore, there is a need to devise a synchronizing program that can improve conception, allow early pregnancy diagnosis, reduce early embryonic losses, and provide an early clue for pregnancy diagnosis and establishment. The present study aimed (1) to determine the effect of administration of different GnRH doses at day 20 of artificial insemination (AI) on the reproductive performance of buffaloes and (2) to observe the influence of synchronization protocol, parity, age, milk production, and body condition score (BCS) on early embryonic loss and progesterone (P4) levels in crossbred buffaloes. Methods: Crossbred buffaloes (n = 101) were synchronized using the GPGMH protocol. At day 20 of AI, the synchronized buffaloes were randomly divided into four groups and administrated GnRH doses (0, 100, 150, and 200 µg). The buffaloes were monitored for ovarian dynamics, P4 level, non-return rate, embryonic/fetal losses, and pregnancy rates. The previously synchronized buffaloes were also classified for synchronization protocol (with or without GnRH), parity (nulli- or multiparous), milk production (high or low), BCS (low, medium, or good) or age (>3 or < 3 years) groups for observing the embryonic loss and P4 level variations. Results: The results indicated no difference (P > 0.05) in CL size, P4 level, pregnancy rate and embryo/fetal losses across the treatment groups at different observation periods. There was a high (P < 0.05) incidence of early embryonic mortality in aged, multiparous, low BCS and low milk-producing buffaloes treated without GnRH. Conclusion: The data suggest that GnRH 200 µg at day 20 of AI improves embryo survival and pregnancy maintenance in crossbred buffaloes.

Use of GnRH Treatment Based on Pregnancy-Associated Glyco-Proteins (PAGs) Levels as a Strategy for the Maintenance of Pregnancy in Buffalo Cows: A Field Study.

The aim of the study was to evaluate the effects of GnRH administrated at day 35 after artificial insemination (AI) on the reproductive performance of buffalo cows. In ten buffalo farms in the period January−February, 481 buffalo cows were subjected to estrus synchronization protocol and fixed-time artificial insemination (Ovsynch−TAI program). Radioimmunoassays (RIA) for pregnancy-associated glycoproteins (PAGs) were used to detect pregnancy at day 28 after AI (cut-off value: ≥1 ng/mL). Among pregnant subjects, those with PAG values between 1 and 2.5 ng/mL were considered at risk of embryonic mortality (EM) and were assigned into two groups: treated (T; n = 57) control (C; n = 57). Treated buffaloes received 0.01 mg of buserelin acetate intramuscularly on day 35 after AI, whereas control buffaloes received no treatment. The pregnancy diagnosis was confirmed at day 60 through PAGs level and rectal palpation. The treatment with GnRH had a significant effect (p < 0.001) in reducing EM. Between days 28 and 60 after AI, the animals that experienced EM were only 2/57 in the T group, while were 13/57 in the C group. Moreover, GnRH treatment produced a significant increase (p < 0.001) in the PAG concentration between day 28 and day 60. Administration of GnRH at day 35 after AI in animals considered at risk of low embryo survival based on PAG levels allowed a reduction in pregnancy losses and improved the pregnancy rate during low-breeding season in buffalo.

Efecto de la reubicación de nidos en el éxito reproductivo de la tortuga marina Lepidochelys olivacea (Testudinata: Cheloniidae) / Effect of nest relocation on the reproductive success of the marine turtle Lepidochelys olivacea (Testudinata: Cheloniidae)

Resumen Introducción: Para incrementar el número de crías de tortugas marinas, es necesario mejorar estrategias de conservación, como incubación de nidos, en condiciones de vivero que contrarresten los efectos de las condiciones climáticas extremas. Objetivo: Comparar cinco parámetros de éxito reproductivo (éxito de eclosión, huevos sin desarrollo aparente, crías muertas, mortalidad embrionaria y período de incubación) de la tortuga marina Lepidochelys olivacea. Métodos: Se evaluó la incubación de nidos bajo dos períodos de reubicación de nidos (P1 ~28.8 °C agosto-septiembre y P2 ~27.1 °C octubre-noviembre, temperatura ambiental promedio, bajo condiciones de vivero, en el 2018 en Guerrero, México. Resultados: Se encontraron diferencias significativas en el éxito de eclosión y la mortalidad embrionaria entre los períodos de reubicación de nidos (P < 0.001). En P1, se observaron valores más bajos de éxito de eclosión (77.0 % P1 vs 88.6 % P2) y valores más altos de mortalidad embrionaria (13.7 % P1 vs 3.3 % P2) comparados con los de P2. Es importante señalar que, en el presente estudio la mortalidad embrionaria se presentó en una etapa tardía de desarrollo, es decir, en embriones casi completamente desarrollados. No se encontraron diferencias entre periodos respecto a los parámetros de huevos sin desarrollo aparente, crías muertas y período de incubación. Conclusiones: Las diferencias entre las condiciones ambientales durante el primer período de reubicación de nidos en comparación con el segundo período parecen afectar el éxito de eclosión y mortalidad embrionaria de L. olivacea. Por lo tanto, es importante tomar medidas al respecto durante esta etapa de incubación para tratar de mejorar la incubación de nidos bajo condiciones de vivero.

Abstract Introduction: In order to increase the number of sea turtle hatchlings, it is necessary to improve conservation strategies, such as nest incubation in hatchery conditions that counteract the effects of extreme climatic conditions. Objective: To compare five reproductive success parameters (hatching success, eggs with no apparent embryonic development, dead hatchlings, embryonic mortality, and incubation period) of the sea turtle Lepidochelys olivacea. Methods: The incubation of nests was evaluated under two periods of nest relocation, P1 ~28.8 °C (August and September) and P2 ~27.1 °C (October and November), average ambient temperature, under hatchery condition, in 2018 in Guerrero, Mexico. Results: Significant differences were found in hatching success and embryonic mortality between nest relocation periods (P < 0.001). In P1, lower values of hatching success (77.0 % P1 vs 88.6 % P2) and higher values of embryonic mortality (13.7 % P1 vs 3.3 % P2) were observed compared to those of P2. It's important pointing that, in the present study, embryonic mortality occurred at a late stage of development, that is, in almost fully developed embryos. No differences were found between periods regarding the parameters eggs with no apparent embryonic development, dead hatchlings and incubation period. Conclusions: The differences between the environmental conditions during the first period of nest relocation compared to the second period, respectively, seem to affect the hatching success and embryonic mortality of L. olivacea. Therefore, it is important to take action on this issue during this incubation stage to try to improve the incubation of nests under hatchery conditions.

Recent Possibilities for the Diagnosis of Early Pregnancy and Embryonic Mortality in Dairy Cows.

One of the most recent techniques for the on-farm diagnosis of early pregnancy (EP) in cattle is B-mode ultrasonography. Under field conditions, acceptable results may be achieved with ultrasonography from Days 25 to 30 post-AI. The reliability of the test greatly depends on the frequency of the transducer used, the skill of the examiner, the criterion used for a positive pregnancy diagnosis (PD), and the position of the uterus in the pelvic inlet. Non-pregnant animals can be selected accurately by evaluating blood flow in the corpus luteum around Day 20 after AI, meaning we can substantially improve the reproductive efficiency of our herd. Pregnancy protein assays (PSPB, PAG-1, and PSP60 RIA, commercial ELISA or rapid visual ELISA tests) may provide an alternative method to ultrasonography for determining early pregnancy or late embryonic/early fetal mortality (LEM/EFM) in dairy cows. Although the early pregnancy factor is the earliest specific indicator of fertilization, at present, its detection is entirely dependent on the use of the rosette inhibition test; therefore, its use in the field needs further developments. Recently found biomarkers like interferon-tau stimulated genes or microRNAs may help us diagnose early pregnancy in dairy cows; however, these tests need further developments before their general use in the farms becomes possible.

Research Note: Effects of preincubation and higher initiating incubation temperature of long-term stored hatching eggs on hatchability and day-old chick and yolk sac weight.

We studied the effect of increased initial incubation temperature and repeated preincubation of 35-d stored eggs from 46-week-old Ross 308 parental stock on the hatchability and day-old chick and yolk sac weight. Two different temperatures were applied during the first 36 h and they were combined with 4 preincubation treatments during storage. One half of the hatching eggs (2,400) were incubated for the first 36 h at an incubation temperature of 38.3°C, and the second half were incubated at a higher temperature of 39.2°C. Four different preincubations were applied; none, once at the 7th d of hatching egg storage, twice at the 7th and 12th d of storage and 3 times at the 7th, 12th and 19th d of storage. Both preincubation and increased temperature had negative effects on hatchability (P < 0.001). The interaction between these 2 factors was also significant (P < 0.05). These 2 factors also negatively affected early and late embryonic mortality (P < 0.001). However, middle embryonic mortality was not influenced. Live weight, weight of residual yolk sac, and yolk sac proportion were not affected by repeated preincubation nor by increased temperature over the first 36 h of incubation (P > 0.05). A higher initial temperature decreased chick yolk free body mass (P < 0.05). Although neither increased initial temperature in the setter nor repeated preincubation affected one-day-old chick weights, these treatments were not suitable for long-term stored eggs because of decreased hatchability and impairment of one day chick yolk free body mass.

Coping with large litters: the management of neonatal piglets and sow reproduction.

As a result of intensive breeding, litter size has considerably increased in pig production over the last three decades. This has resulted in an increase in farrowing complications. Prolonged farrowing will shorten the window for suckling colostrum and reduce the chances for high-quality colostrum intake. Studies also agree that increasing litter sizes concomitantly resulted in decreased piglet birth weight and increased within-litter birth weight variations. Birth weight, however, is one of the critical factors affecting the prognosis of colostrum intake, and piglet growth, welfare, and survival. Litters of uneven birth weight distribution will suffer and lead to increased piglet mortality before weaning. The proper management is key to handle the situation. Feeding strategies before farrowing, management routines during parturition (e.g., drying and moving piglets to the udder and cross-fostering) and feeding an energy source to piglets after birth may be beneficial management tools with large litters. Insulin-like growth factor 1 (IGF-1)-driven recovery from energy losses during lactation appears critical for supporting follicle development, the viability of oocytes and embryos, and, eventually, litter uniformity. This paper explores certain management routines for neonatal piglets that can lead to the optimization of their colostrum intake and thereby their survival in large litters. In addition, this paper reviews the evidence concerning nutritional factors, particularly lactation feeding that may reduce the loss of sow body reserves, affecting the growth of the next oocyte generation. In conclusion, decreasing birth weight and compromised immunity are subjects warranting investigation in the search for novel management tools. Furthermore, to increase litter uniformity, more focus should be placed on nutritional factors that affect IGF-1-driven follicle development before ovulation.

The effect of double-dose GnRH injections on reproductive performance parameters following short-term progestagen administration in lactated Awassi ewes during the non-breeding season.

The present study was aimed to investigate the effects of double-dose gonadotropin-releasing hormone (GnRH) injection on the induction of oestrus and some reproductive performance parameters in Awassi ewes during the non-breeding season. In the study, 100 ewes were treated with a vaginal sponge containing 60 mg medroxyprogesterone acetate for 7 days in the anoestrus (day 0). PMSG 500 IU and 250 µg cloprostenol sodium were injected on the day of removal of the sponge (day 7). Ewes in Group 1 (n = 31) were not subjected to any hormonal treatment. Ewes in Group 2 (n = 31) were given 50 µg GnRH 48th hour after removal of the sponge. Ewes in Group 3 (n = 33) were given 50 µg GnRH 48th hour after the removal of the sponge and 50 µg GnRH 12th day after post-mating. The results obtained in the study showed that there were no statistical differences between the Groups 1, 2 and 3 in terms of oestrus rates (82.8%, 68.9%, 72.7%), conception rates (66.7%, 55.0%, 54.2%), multiple pregnancy rates (28.5%, 50.0%, 30.7%) and litter sizes (1.28, 1.50, 1.31). No significant increases in P4 concentration were observed in Group 3 treated with GnRH at the 12th day after post-mating; however, a numerically lower (p > 0.05) late embryonic-early fetal mortality rate was observed in Group 3 (0%), when compared with the values obtained in Group 1 (12.5%) and Group 2 (9.1%). In conclusion, after short-term progestagen administration during the non-breeding season, double-dose GnRH injections did not increase P4 concentration and had no significant differences on reproductive performance parameters among groups.

Approaches to Identify Pregnancy Failure in Buffalo Cows.

The aim of this work was to find the best strategy to diagnose pregnancy failures in buffalo. A total of 109 animals belonging to a buffalo herd subjected to a synchronization and artificial insemination (AI) program were enrolled in this study. Blood samples were collected at days 0, 14, 25, 28 and 40 after AI for the determination of progesterone (P4) and pregnancy-associated glycoproteins (PAGs) by the radioimmunoassay (RIA) method. Transrectal ultrasonography was performed on day 25, 28 and 40 after AI to monitor pregnancy. The animals included in the data analysis were assigned ex post in pregnant (n = 50) and mortality (n = 12) groups. By ultrasonography, the predictive sign of mortality was the heartbeat. At day 25, the PAGs concentration was significant in predicting embryonic mortality with respect to ultrasonography and P4, at the cut-off of 1.1 ng/mL. At day 28, either PAGs, at a cut-off of 2.2 ng/mL, or ultrasonography, with no detection of heartbeat, were highly predictive of embryonic mortality. PAGs were the best marker (p < 0.05) for predicting embryonic mortality between 25 and 40 days of gestation in buffalo. Its utilization as a diagnostic tool can influence management decisions in order to improve farm reproductive management.

Congenital Malformations in Sea Turtles: Puzzling Interplay between Genes and Environment.

The completion of embryonic development depends, in part, on the interplay between genetic factors and environmental conditions, and any alteration during development may affect embryonic genetic and epigenetic regulatory pathways leading to congenital malformations, which are mostly incompatible with life. Oviparous reptiles, such as sea turtles, that produce numerous eggs in a clutch that is buried on the beach provide an opportunity to study embryonic mortality associated with malformations that occur at different times during development, or that prevent the hatchling from emerging from the nest. In sea turtles, the presence of congenital malformations frequently leads to mortality. A few years ago, a detailed study was performed on external congenital malformations in three species of sea turtles from the Mexican Pacific and Caribbean coasts, the hawksbill turtle, Eretmochelys imbricata (n = 23,559 eggs), the green turtle, Chelonia mydas (n = 17,690 eggs), and the olive ridley, Lepidochelys olivacea (n = 20,257 eggs), finding 63 types of congenital malformations, of which 38 were new reports. Of the three species, the olive ridley showed a higher incidence of severe anomalies in the craniofacial region (49%), indicating alterations of early developmental pathways; however, several malformations were also observed in the body, including defects in the carapace (45%) and limbs (33%), as well as pigmentation disorders (20%), indicating that deviations occurred during the middle and later stages of development. Although intrinsic factors (i.e., genetic mutations or epigenetic modifications) are difficult to monitor in the field, some environmental factors (such as the incubation temperature, humidity, and probably the status of feeding areas) are, to some extent, less difficult to monitor and/or control. In this review, we describe the aetiology of different malformations observed in sea turtle embryos, and provide some actions that can reduce embryonic mortality.

Effects of flock age, storage temperature, and short period of incubation during egg storage, on the albumen quality, embryonic development and hatchability of long stored eggs.

1. The effect of breeder flock age, storage temperature and a short period of incubation during egg storage (SPIDES) on albumen quality, development of blastoderm, and hatchability of long-stored eggs was evaluated.2. Hatching eggs were collected from 28-week-old (young) and 40-week-old (prime) Ross female line grandparent flocks and were stored for 14 d at 12, 15 or 18°C. During storage, the eggs were either kept continuously in the storage room (control) or were subjected to SPIDES treatment.3. Embryonic development was more advanced in eggs from the prime flock, exposed to SPIDES and warmer (18°C) storage temperature (P ≤ 0.05). There was a difference in the albumen pH for flock ages (P < 0.05), but the SPIDES treatment did not affect albumen height and pH (P > 0.05). On d 14 of storage, albumen pH was positively (P < 0.05) correlated with storage temperature. Hatchability was higher in the prime flock (P < 0.05).4. At both flock ages, hatchability increased (P < 0.05) by storing the eggs at 15°C, compared to 18°C, with 12°C intermediate. The hatchability improvement was due to reduced early embryonic mortality.5. The SPIDES treatment decreased late embryonic mortality and the percentage of second-grade chicks (P < 0.05), which increased the hatchability of fertile eggs (P < 0.05). SPIDES only reduced (P < 0.05) early embryonic mortality in eggs stored at 18°C.6. The highest hatchability was observed in the eggs stored at 15°C and exposed to one SPIDES treatment during 14 d storage.

Effect of egg storage duration and egg turning during storage on egg quality and hatching of broiler hatching eggs.

In commercial hatcheries, it is common to store eggs before incubation. One practice to improve hatchability consists in egg turning during this storage. This work aims to highlight the effects of turning on the physicochemical aspects of eggs and, consequently, how this turning can influence the hatching of chicks. An experiment was conducted to evaluate the effects of storage duration and egg turning during storage on egg quality, hatchability, and residual analysis. A total of 7 500 hatching eggs were collected from a 55-week-old commercial Cobb500 breeder flock and storage according to the treatments. The experiment was completely randomized in a 3×2 factorial design with three storage periods (4, 8, and 12 days) and egg turning (180° turn of eggs once a day) or no turning during storage, totaling six treatments. Regardless of turning, eggs stored for 4 days weighed more than turned eggs stored for 8 and 12 days, which were similar (P < 0.05). Non-turned eggs experienced an increase in relative shell weight with increased storage duration, and non-turned eggs stored for 4 and 8 days differed from non-turned eggs stored for 12 days (P < 0.05). Albumen pH of turned eggs stored for 4 and 8 days was lower than that of non-turned eggs stored for the same durations (P < 0.05). Albumen pH of turned eggs increased as storage duration increased (P < 0.05). Egg turning increased hatching by 2.02% over that of non-turning (P < 0.05). Eggs stored for 12 days, irrespective of turning, had higher late embryonic mortality (P < 0.05) compared to the other treatments. It was concluded that turning eggs during pre-incubation storage was adequate to improve hatchability of fertile eggs. Storing fertile eggs for 12 days is harmful to egg quality and increases embryo mortality even if eggs were turned.

Research Note: Storage period and prewarming temperature effects on synchronous egg hatching from broiler breeder flocks during the early laying period.

The effects of the storage period and prewarming temperature on embryonic mortality, hatchability, and synchronous hatching of broiler eggs were investigated. Eggs were obtained from commercial flocks of Ross 308 broiler breeders at 27 and 28 wk of age for trials 1 and 2, respectively. In both trials, 2,400 eggs were stored for 4 d (short) or 11 d (long) at 18°C (64.4°F) and 75% RH and were randomly assigned to 2 groups at either a prewarming temperature of 26.1°C (79°F, low) or 29.4°C (85°F, high) for 8 h before setting. The eggs were transferred from setters to hatching baskets at 444 h (18.5 d) of incubation. The hatched chicks were counted at 6-h intervals between 468 h and 516 h of incubation and categorized as early, middle, or late hatching. The eggs stored for 4 d hatched earlier than the eggs stored for 11 d (P < 0.05). An increased prewarming temperature (29.4°C) resulted in a 1.0-h shorter incubation duration, but this difference was not significant (P = 0.064). An interaction between the storage period and prewarming temperature was observed for middle- and late-hatched chicks (P < 0.05). No interactions between the storage period and prewarming temperature were observed for hatchability of fertile eggs or embryonic mortality; however, a significant interaction was found between the storage period and prewarming temperature on the second-quality chick percentage (P < 0.05). The eggs stored for 11 d had a significantly reduced hatchability of fertile eggs owing to increased embryonic mortality than short-stored eggs (P < 0.05). The interaction effect indicated that eggs held for 8 h with prewarming at 29.4°C after 11 d of storage had more middle- and fewer late-hatched chicks and improved chick quality than those that received the 26.1°C prewarming treatment (P < 0.05), but no significant difference was found among the prewarming treatments for eggs stored for 4 d. This study demonstrated that prolonged egg storage resulted in reduced hatchability, increased incubation duration, and an asynchronous hatching time. Moreover, increasing the prewarming temperature could be used to promote uniformity among embryos through synchronous hatching, thus improving broiler flock uniformity and performance of the prolonged stored eggs.