The high-fertility cycle: How timely pregnancies in one lactation may lead to less body condition loss, fewer health issues, greater fertility, and reduced early pregnancy losses in the next lactation.

Body condition loss during early lactation varies among cows in the herd and is associated with future health and reproductive outcomes. The objective of this study was to gain a greater understanding of the relationship between previous calving interval and body condition change during the first 30 d in milk (DIM) and their relationship to subsequent fertility and health variables and sex ratio at birth. Dry cows and heifers (n = 851) from a single farm entered the study approximately 25 d before the due date. They were evaluated and given a body condition score on a 1-to-5 scale with 0.1-point increments weekly until parturition. Body condition score was assessed within 1 wk of parturition and then again 27 to 33 DIM. Previous calving interval, gestation length, periparturient health events (giving birth to twins, dystocia, retained placentas, ketosis, metritis, and displaced abomasum), sire net merit ($), and milk data were used for each cow as recorded in PCDART (Dairy Records Management Systems, Raleigh, NC) by the herd managers. Longer previous calving intervals were related to greater body condition at parturition and body condition loss during the first 30 DIM. A 75% greater proportion of cows with a calving-to-pregnancy interval shorter than 130 d maintained or gained body condition during the first 30 DIM compared with cows with calving-to-pregnancy intervals longer than 130 d. Multiparous cows that maintained or gained body condition (n = 144) had greater pregnancies per AI following first service compared with cows that lost body condition (n = 577) during the first 30 DIM when health events were considered or removed. When cows with health events were considered, multiparous cows that maintained or gained body condition had a greater percentage pregnant by 130 DIM compared with cows that lost body condition (67 vs. 55%; n = 522). Cows that lost body condition during the first 30 DIM regardless of health events experienced greater pregnancy loss (n = 224) between 35 and 60 d after first AI (0.0 vs. 6.7%) compared with cows that maintained or gained body condition (n = 69) during that period. Based on data in this study from a single herd, maintaining a cycle of pregnancy before 130 DIM may reduce the amount of body condition lost after the next parturition, enhance subsequent pregnancies per AI, and reduce the possibility of early pregnancy loss. We refer to this phenomenon as the high-fertility cycle.

Evaluation of shortened timed-AI protocols for resynchronization of ovulation in multiparous Holstein dairy cows.

The objective was to compare three shortened protocols for timed-AI (TAI) on ovarian responses, pregnancy per AI (P/AI) and pregnancy loss after resynchronization of ovulation in multiparous Holstein cows. Cows (n = 370), at one location, were randomly assigned at non-pregnancy diagnosis (approximately 32 d after AI) to one of three ovulation resynchronization protocols. Cows in the OS group received a 5-d Ovsynch [100 µg GnRH on Day 1, 500 µg cloprostenol (PGF) on Days 6 and 7, GnRH on Day 8.5 and TAI on Day 9 (16 h after second GnRH)]. Cows in the OS + P4 (progesterone) group received a 5-d Ovsynch as described for OS group plus an intravaginal device (Cue-Mate), containing 1.56 g of progesterone (P4), between Days 1 and 6. Cows in the J-synch group received a Cue-Mate and 2.5 mg of estradiol benzoate (EB) on Day 0, PGF and Cue-Mate removal on Day 6, another PGF on Day 7, and 100 µg of GnRH on Day 8.5, with TAI on Day 9. Ovarian response and pregnancy status at 32 and 60 d after the resynchronization TAI were determined by transrectal ultrasonography. Blood samples were collected at first PGF treatment and at TAI from a subset of 40 cows per group to determine P4 concentrations. Percentage of cows with CL at initiation of the protocol did not differ (P > 0.05) among resynchronization groups. Plasma P4 concentrations at first PGF treatment were greater (P < 0.01) in cows that received a Cue-Mate (OS + P4 and J-synch) compared to OS cows. Luteal regression was greater (P < 0.01) for J-synch (88.6%) compared with OS (76.9%) and OS + P4 (78.8%). More (P < 0.01) cows in the OS + P4 and J-synch groups had their estrous cycle synchronized and were pregnant at 32 d after TAI (48.7 and 34.7%, 67.8 and 48.0%, and 72.4 and 50.0% for OS, OS + P4 and J-synch, respectively). However, more cows subjected to J-synch remained pregnant at 60 d after TAI and, hence, had fewer (P < 0.05) pregnancy losses (19.2, 18.8 and 5.0% for OS, OS + P4 and J-synch, respectively). In summary, cows resynchronized with either OS + P4 or J-synch had greater P4 concentrations at first PGF treatment and a greater response to treatments compared to cows subjected to OS. Although OS + P4 and J-synch resynchronization protocols resulted in increased P/AI at 32 d, pregnancy losses were significantly reduced in cows subjected to the J-synch protocol.

Syndromic surveillance of abortions in beef cattle based on the prospective analysis of spatio-temporal variations of calvings.

Our objective was to study the ability of a syndromic surveillance system to identify spatio-temporal clusters of drops in the number of calvings among beef cows during the Bluetongue epizootic of 2007 and 2008, based on calving seasons. France was partitioned into 300 iso-populated units, i.e. units with quite the same number of beef cattle. Only 1% of clusters were unlikely to be related to Bluetongue. Clusters were detected during the calving season of primary infection by Bluetongue in 28% (n = 23) of the units first infected in 2007, and in 87% (n = 184) of the units first infected in 2008. In units in which a first cluster was detected over their calving season of primary infection, Bluetongue was detected more rapidly after the start of the calving season and its prevalence was higher than in other units. We believe that this type of syndromic surveillance system could improve the surveillance of abortive events in French cattle. Besides, our approach should be used to develop syndromic surveillance systems for other diseases and purposes, and in other settings, to avoid "false" alarms due to isolated events and homogenize the ability to detect abnormal variations of indicator amongst iso-populated units.

Changes in leukocyte subsets of pregnant gilts experimentally infected with porcine reproductive and respiratory syndrome virus and relationships with viral load and fetal outcome.

In spite of more than two decades of extensive research, the understanding of porcine reproductive and respiratory syndrome virus (PRRSv) immunity is still incomplete. A PRRSv infection of the late term pregnant female can result in abortions, early farrowings, fetal death, and the birth of weak, congenitally infected piglets. The objectives of the present study were to investigate changes in peripheral blood mononuclear cell populations in third trimester pregnant females infected with type 2 PRRSv (NVSL 97-7895) and to analyze potential relationships with viral load and fetal mortality rate. PRRSv infection caused a massive, acute drop in total leukocyte counts affecting all PBMC populations by two days post infection. Except for B cells, cell counts started to rebound by day six post infection. Our data also show a greater decrease of naïve B cells, T-helper cells and cytolytic T cells than their respective effector or memory counterparts. Absolute numbers of T cells and γδ T cells were negatively associated with PRRSv RNA concentration in gilt serum over time. Additionally, absolute numbers of T helper cells may be predictive of fetal mortality rate. The preceding three leukocyte populations may therefore be predictive of PRRSv-related pathological outcomes in pregnant gilts. Although many questions regarding the immune responses remain unanswered, these findings provide insight and clues that may help reduce the impact of PRRSv in pregnant gilts.

Neospora caninum infection as a cause of reproductive failure in a sheep flock.

Neospora caninum has been detected only sporadically in cases of ovine abortion, and it has therefore traditionally been considered as an unimportant parasite in small ruminants. This study was carried out with the aim of identifying the pathogen causing serious reproductive problems on a commercial sheep farm. Sera from all rams and ewes tested negative for antibodies against Border disease virus, Schmallenberg virus and Coxiella burnetii, and infections by these agents were therefore ruled out. Nevertheless, seropositivity to N. caninum and/or Toxoplasma gondii was detected, although the seroprevalence was higher in the case of N. caninum. The percentage of lambings and the number of lambs per dam were significantly lower in ewes that were seropositive to N. caninum while no effect on these parameters was detected in ewes that were seropositive to T. gondii. There was also no evidence of infection by T. gondii in the foetal/lamb tissues analyzed by PCR and/or immunohistopathological techniques. On the contrary, the DNA of N. caninum was detected in 13 out of 14 foetuses/lambs descendant from dams seropositive to this parasite. Characteristic lesions caused by N. caninum and/or its antigen were also detected. Genotyping of the N. caninum DNA revealed only two closely related microsatellite multilocus genotypes. The results clearly demonstrate that infection by N. caninum was the cause of the low reproductive performance of this sheep flock.

Neospora caninum infection during early pregnancy in cattle: how the isolate influences infection dynamics, clinical outcome and peripheral and local immune responses.

This work studies the influence of Neospora caninum intra-species diversity on abortion outcome, infection dynamics in terms of parasite dissemination and peripheral-local immune responses in pregnant cattle. Animals were intravenously inoculated at day 70 of pregnancy with 107 tachyzoites of two isolates showing marked differences in virulence in vitro and in pregnant mouse models: Nc-Spain7, a high virulence isolate, and Nc-Spain8, a low-to-moderate virulence isolate. After inoculation, pregnancy was monitored, and dams were culled when foetal death was detected. Foetal mortality occurred in all infected heifers between days 24 and 49 post-infection (pi), however, it was detected sooner in Nc-Spain7-infected animals (median day = 34) than those inoculated with Nc-Spain8 (median day = 41) with a trend towards significance (P < 0.11). Similar histological lesions were observed in placentomes and in most of the foetuses from the two infected groups. However, parasites were more frequently detected in the placenta and foetuses by PCR and in the foetal brain by immunohistochemistry in Nc-Spain7-infected animals. Specific antibodies were detected starting at day 13 post-infection in all infected cattle, with higher IgG levels in Nc-Spain7-infected group. IFN-γ and IL-4 profiles also varied between infected groups in PBMC stimulation assays. Infected animals showed significant increases in their cytokine mRNA levels (IFN-γ, IL-4, IL-10, IL-12p40 and TNF-α) in the caruncle at time of foetal death. Differences between the infected groups were also observed for cytokine profiles. These results demonstrate the influence of the N. caninum isolate on foetal death outcome, infection dynamics and immune responses in cattle.

The role of leptospirosis in reproductive disorders in horses.

Leptospirosis is a zoonotic disease of global importance and has a worldwide distribution. This infection displays clear seasonal nature in some regions of the tropics, where the rainy season is marked by high temperatures. Household and wild animals carry leptospires and contribute to their dissemination in nature. Transmission mainly occurs by contact with water contaminated with the urine of infected animals, and consequently, it is quite widespread especially in times of rain, since many areas are subject to flooding and have poor sanitation. Serological tests demonstrate that Leptospira sp. infection in horses occurs worldwide and that the predominant serovar may vary depending on the region or infection sources. Besides systemic and ocular manifestations, leptospirosis in horses has been recognized as an important disease of the reproductive system, since it leads to the birth of weak foals, stillbirths or neonatal mortality, and mainly to abortion, usually after the sixth month of pregnancy. In this context, this review aims to gather and discuss information about the role of leptospirosis in reproductive disorders in horses.

Abortos por Neosporacaninum em bovinos do sul de Minas Gerais / Neosporacaninum abortions in cattle in southern Minas Gerais, Brazil

Este estudo avaliou a participação de Neospora caninum em casos de abortos em bovinos provenientes de propriedades rurais da região sul de Minas Gerais por meio de análises histopatológicas, imuno-histoquímicas (IHQ) e pela reação em Cadeia de Polimerase (PCR). O material utilizado foi obtido de um estudo retrospectivo de casos de aborto recebidos pelo Setor de Patologia Veterinária da Universidade Federal de Lavras e de fetos necropsiados durante os anos de 2011 a 2013. De 60 fetos estudados, 30 (50%) tinham lesões microscópicas. Destes, 19 (63%) apresentaram lesões compatíveis com aborto por N. caninum, caracterizadas principalmente por encefalite não supurativa multifocal, necrose e gliose multifocal, assim como, miocardite e miosite não supurativa. Em 14 fetos chegou-se ao diagnóstico definitivo. Destes, cinco tiveram sua confirmação somente pela marcação IHQ e cinco foram positivos somente na PCR. Quatro fetos foram positivos tanto na IHQ quanto na PCR. Cinco fetos, provenientes do estudo retrospectivo apresentaram lesões compatíveis com N. caninum, mas a presença do protozoário não foi confirmada pela marcação IHQ. Os achados demonstram que o N. caninum é um importante agente associado ao aborto em bovinos na região sul de Minas Gerais. Para tanto, além das lesões microscópicas a associação entre a IHQ e a técnica de PCR foi essencial para a confirmação do diagnóstico.

The present study evaluates the participation of Neospora caninum in bovine abortions from farms in the southern region of Minas Gerais state, Brazil, through histopathological, immunohistochemical (IHQ) analysis and DNA detection by polymerase chain reaction (PCR). The material used in this study was obtained through retrospective study of bovine abortion cases received by the Setor de Patologia Veterinária da Universidade Federal de Lavras and by necropsies performed in fetuses from 2011 to 2013. From 60 fetuses studied, 30 (50%) had microscopic lesions; 19 (63%) of them had histologic lesions compatible with N. caninum abortion, characterized by multifocal non-suppurative encephalitis, necrosis and gliosis in the central nervous system and multifocal nonsuppurative myocarditis and myositis. From the 19 fetuses with protozoa lesions in 14 the final diagnosis was performed; five were confirmated only by IHQ staining and five were positive only by PCR. Four fetuses were positive in IHC and in PCR. In five fetuses from the retrospective study lesions compatible with N. caninum were seen, but the presence of the protozoan was not confirmed by IHQ labeling. The findings demonstrate that N. caninum is an important agent associated with abortion in cattle from Minas Gerais. Therefore, beyond the microscopic lesions association between IHC and PCR was essential to confirm the diagnosis.

Desempenho reprodutivo entre receptoras bovinas não contaminadas e naturalmente infectadas por Neospora caninum, após a transferência de embriões / Reproductive performance in bovine receipts non infected and naturally infected with Neospora caninum after embryo transfer

O uso do conhecimento de biotécnicas para a melhoria da produção de bens e serviços tem avançado significativamente. O controle de doenças infecciosas continua a representar o maior obstáculo para a saúde dos animais. A perda embrionária pode ser responsável pelo aumento de prejuízos econômicos isolados para os produtores de bovinos. A infecção por Neospora caninum tem emergido como uma importante doença reprodutiva e, em vários países, tem sido diagnosticada como principal causa de aborto. O objetivo desse trabalho foi comparar o desempenho reprodutivo em receptoras bovinas não contaminadas e naturalmente infectadas por Neospora caninum após a transferência de embriões (TE). A escolha dos animais (n=395) para o experimento foi realizada através de avaliação ginecológica, via palpação transretal. As vacinações seguiram protocolo sanitário recomendado para a TE. O manejo nutricional foi baseado no National Research Council (NRC, 1999). A TE de embriões descongelados foi feita após a sincronização do ciclo estral das receptoras. Para a avaliação do desempenho reprodutivo se utilizou de ultrassonografia transretal. A identificação das receptoras positivas para Neospora caninum realizou-se através do teste de ELISA e, para as amostras reagentes, confirmação através de imunofluorescência indireta (IFI). Os dados foram analisados utilizando Past® e foram considerados estatisticamente significantes (P<0,01). Os resultados mostram uma taxa de prenhes (n=191) de 48,35%, seguida de uma taxa de abortos aos 60 dias de gestação (n=14) de 3,5% e abortos ao sexto mês de gestação (n=12) de 3,04%. Esses resultados tornam-se relevantes quando se leva em consideração que, receptoras infectadas pelo protozoário não apresentaram uma taxa elevada de perdas gestacionais. A insignificância estatística dos dados obtidos nesse estudo confere a segurança em sugerir que não há necessidade em implantar o diagnóstico ou controle prévios para Neosporose em rebanhos aptos a TE.

The use of knowledge in biotechnologies for improving the production of goods and services has advanced significantly. The control of infectious diseases continues to represent the most obstacle to the health of animals. The embryonic loss may be responsible for the increase in economic losses for producers isolated from cattle. Infection with Neospora caninum has emerged as an important reproductive disease and, in several countries, has been diagnosed as the main cause of abortion. The aim of this study was to evaluate the reproductive performance in not contaminated and naturally infected with Neospora caninum bovine receipt after embryos transfer (ET). The choice of animals (n=395) for the experiment was performed by gynecological evaluation, via transrectal palpation. Vaccinations recommended for health protocol followed the ET. Nutritional management was based on the National Research Council (NRC, 1999). The ET of thawed embryos was made after the synchronization of the estrous cycle of the receipts. To evaluate the reproductive performance of transrectal ultrasonography was used. The identification of the positive receipts for Neospora caninum was performed by ELISA and reagents for samples, confirmation by indirect immunofluorescence (IIF). Data were analyzed using Past® and were considered statistically significant (P<0.01). The results show a rate of pregnant (n=191) of 48.35%, followed by an abortion rate at 60 days of gestation (n=14) and 3.5% of abortions in the sixth month of gestation (n=12) of 3.04%. These results become relevant when taking into consideration that infected receipts by the protozoan not showed a high rate of pregnancy loss. The statistical insignificance of the data obtained in this study provides the security suggesting that there is no need to deploy the diagnosis or prior control to neosporosis in receipts able to ET.

Increased fertility in lactating dairy cows resynchronized with Double-Ovsynch compared with Ovsynch initiated 32 d after timed artificial insemination.

The objective was to determine if using a Double-Ovsynch protocol [DO; Pre-Resynch: GnRH-7 d-PGF(2α)-3 d-GnRH, 7 d later Breeding-Resynch: GnRH-7 d-PGF(2α)-56 h-GnRH-16 h-timed artificial insemination (TAI)] to resynchronize ovulation after a previous TAI would increase synchrony and pregnancies per AI (P/AI) compared with an Ovsynch protocol initiated 32 d after TAI (D32; GnRH-7 d-PGF(2α)-56 h-GnRH-16 h-TAI). Lactating Holstein cows at various days in milk and prior AI services were blocked by parity and randomly assigned to resynchronization treatments. All DO cows received the first GnRH injection of Pre-Resynch 22 d after TAI, and cows (n=981) diagnosed not pregnant using transrectal ultrasonography 29 d after TAI continued the protocol. Pregnancy status for all D32 cows was evaluated 29 d after TAI so fertility and pregnancy loss could be compared with that of DO cows. All D32 cows received the first GnRH injection of Ovsynch 32 d after TAI, and cows (n=956) diagnosed not pregnant using transrectal palpation 39 d after TAI continued the protocol. In a subgroup of cows from each treatment, ultrasonography (n=751) and serum progesterone (P4) concentrations (n=743) were used to determine the presence of a functional corpus luteum (CL) and ovulation to the first GnRH injection of D32 and Breeding-Resynch of DO (GnRH1), luteal regression after PGF before TAI, and ovulation to the GnRH injection before TAI (GnRH2). Overall, P/AI 29 d after TAI was not affected by parity and was greater for DO compared with D32 cows (39 vs. 30%). Pregnancy loss from 29 to 74 d after TAI was not affected by parity or treatment. The percentage of cows with a functional CL (P4 ≥1.0 ng/mL) at GnRH1 was greater for DO than D32 cows (81 vs. 58%), with most DO cows having medium P4 (60%; 1.0 to 3.49 ng/ml), whereas most D32 cows had either low (42%; <1.0 ng/mL) or high (36%; ≥3.5 ng/mL) P4 at GnRH1. Ovulation to GnRH1 was similar between treatments but was affected by serum P4 at GnRH. Cows with low P4 (<1.0 ng/mL) had the greatest ovulatory response (59%), followed by cows with medium (≥1.0 to 3.49 ng/mL; 38%) and then high (≥3.50 ng/mL; 16%) P4 at GnRH1. A greater percentage of DO cows were synchronized compared with D32 cows (72 vs. 51%) primarily due to a greater percentage of D32 than DO cows without a functional CL at the PGF injection before TAI (35 vs. 17%) or without complete CL regression before GnRH2 (17 vs. 7%). We conclude that DO increased fertility of lactating dairy cows during a resynchronization program primarily by increasing synchronization of cows during the Ovsynch protocol before TAI.

Changes in serum pregnancy-associated glycoprotein, pregnancy-specific protein B, and progesterone concentrations before and after induction of pregnancy loss in lactating dairy cows.

Lactating crossbred dairy cows were synchronized to receive a timed artificial insemination (TAI), and blood samples were collected from all cows from TAI until pregnancy diagnosis 39 d after TAI (period 1), and from pregnant cows from onset of treatment until the end of the experiment (period 2). Cows diagnosed pregnant 39 d after TAI were randomly assigned to 1 of 3 treatments to receive (1) an i.m. injection of saline (CON, n=10); (2) an i.m. injection of PGF(2α) (PGF, n=10); or (3) an intrauterine infusion of 120 mL of hypertonic saline (INF, n=9). During period 1, serum pregnancy-associated glycoprotein (PAG) concentrations began to increase in pregnant cows by 25 d after TAI and differed from those in nonpregnant cows by 27 d after TAI, whereas serum pregnancy-specific protein B (PSPB) concentrations in pregnant cows differed from those in nonpregnant cows by 22 d after TAI. During period 2, time from treatment to cessation of the embryonic heartbeat was greater for PGF than for INF cows (36.0±5.7 vs. 0.2±0.1 h, respectively), and time from treatment to conceptus disappearance was greater for INF than for PGF cows (7.1±3.3 vs. 1.9±0.3 d, respectively). Overall, progesterone concentration was greater for CON and INF than for PGF cows (8.7±2.8, 8.2±3.1, and 1.0±2.3 ng/mL, respectively) due to luteal regression for PGF cows and corpus luteum maintenance for CON and INF cows. Serum PAG and PSPB concentrations differed among CON cows and PGF and INF cows beginning 1 and 2.5 d after treatment for PAG and PSPB, respectively. By 9.5 d after treatment, PAG and PSPB concentrations were similar to those of nonpregnant cows. We conclude that although timing of conceptus expulsion occurred 5.2 d later for INF than for PGF cows, serum PAG and PSPB concentrations decreased at a similar rate from the onset of treatment for both models of pregnancy loss evaluated.

Spontaneous abortion and preterm labor and delivery in nonhuman primates: evidence from a captive colony of chimpanzees (Pan troglodytes).

BACKGROUND: Preterm birth is a leading cause of perinatal mortality, yet the evolutionary history of this obstetrical syndrome is largely unknown in nonhuman primate species. METHODOLOGY/PRINCIPAL FINDINGS: We examined the length of gestation during pregnancies that occurred in a captive chimpanzee colony by inspecting veterinary and behavioral records spanning a total of thirty years. Upon examination of these records we were able to confidently estimate gestation length for 93 of the 97 (96%) pregnancies recorded at the colony. In total, 78 singleton gestations resulted in live birth, and from these pregnancies we estimated the mean gestation length of normal chimpanzee pregnancies to be 228 days, a finding consistent with other published reports. We also calculated that the range of gestation in normal chimpanzee pregnancies is approximately forty days. Of the remaining fifteen pregnancies, only one of the offspring survived, suggesting viability for chimpanzees requires a gestation of approximately 200 days. These fifteen pregnancies constitute spontaneous abortions and preterm deliveries, for which the upper gestational age limit was defined as 2 SD from the mean length of gestation (208 days). CONCLUSIONS/SIGNIFICANCE: The present study documents that preterm birth occurred within our study population of captive chimpanzees. As in humans, pregnancy loss is not uncommon in chimpanzees, In addition, our findings indicate that both humans and chimpanzees show a similar range of normal variation in gestation length, suggesting this was the case at the time of their last common ancestor (LCA). Nevertheless, our data suggest that whereas chimpanzees' normal gestation length is ∼20-30 days after reaching viability, humans' normal gestation length is approximately 50 days beyond the estimated date of viability without medical intervention. Future research using a comparative evolutionary framework should help to clarify the extent to which mechanisms at work in normal and preterm parturition are shared in these species.

Evaluation of the potential effects of abortion on the productive performance of Iranian Holstein dairy cows.

Calving records from the Animal Breeding Center of Iran collected from January 1983 to December 2007 and comprising 1,163,594 Holstein calving events from 2552 herds were used to evaluate the potential effect of abortion occurrence on 305-day milk yield, milk fat yield, fat percentage of milk and milk protein yield in Iranian Holsteins. Statistical analyses of production traits were performed using a linear mixed model procedure. Normal-calved cows had greater 305-day milk production, fat yield and protein yield of milk than abortive-calved cows (P < 0.05). However, abortive-calved cows had the greater milk fat percentage than normal calved cows (P < 0.05). The linear and quadratic effects of age of dam were significant on all of the studied traits (P < 0.05). The results of regression analysis showed that increase in the quadratic effect of age can cause an increase in the fat percentage of milk for all calvings including normal and abortive calvings. Because abortion is one of the most important conditions that limit a cow's ability to produce, maintaining the general health of cattle is important in minimizing the risk of abortion problems.

Luteal blood flow increases during the first three weeks of pregnancy in lactating dairy cows.

The objectives of this experiment were to characterize luteal blood flow in pregnant and non-pregnant cows and to determine its value for early pregnancy diagnosis. Lactating dairy cows (n = 54), 5.2 ± 0.2 y old (mean ± SEM), average parity 2.4 ± 0.2, and ≥ 6 wk postpartum at the start of the study, were used. The corpus luteum (CL) was examined with transrectal color Doppler ultrasonography (10.0-MHz linear-array transducer) on Days 3, 6, 9, 11, 13, 15, 18, and 21 of the estrus cycle (estrus = Day 0). Artificially inseminated cows (n = 40) were retrospectively classified as pregnant (embryonic heartbeat on Day 25; n = 18), nonpregnant (interestrus interval 15 to 21 d, n = 18), or having an apparent early embryonic loss (interestrus interval >25 d, n = 4). There was a group by time interaction (P < 0.001) for luteal blood flow from Days 3 to 18; it was approximately 1.10 ± 0.08 cm(2) (mean ± SEM) on Day 3, and increased to approximately 2.00 ± 0.08 cm(2) on Day 13 (similar among groups). Thereafter, luteal blood flow was numerically (albeit not significantly) greater in pregnant cows, remained constant in those with apparent embryonic loss, and declined (not significantly) between Days 15 and 18 in nonpregnant cows. Luteal blood flow was greater in pregnant than in nonpregnant (P < 0.05) and nonbred cows (P < 0.05, n = 14) on Day 15 (2.50 ± 0.16, 2.01 ± 0.16, and 2.00 ± 0.18 cm(2), respectively) and on Day 18 (2.40 ± 0.19, 1.45 ± 0.19, and 0.95 ± 0.21 cm(2)). In cows with apparent early embryonic loss, luteal blood flow was 2.00 ± 0.34 and 2.05 ± 0.39 cm(2) on Days 15 and 18, which was less (not significantly) than in pregnant cows, but greater (P < 0.05) than in nonbred cows on Day 18. Although mean luteal blood flow was significantly greater in pregnant than nonpregnant (and nonbred) cows on Days 15 and 18, due to substantial variation among cows, it was not an appropriate diagnostic tool for pregnancy status.

Resynchronization strategies to improve fertility in lactating dairy cows utilizing a presynchronization injection of GnRH or supplemental progesterone: I. Pregnancy rates and ovarian responses.

Objectives were to evaluate 3 resynchronization protocols for lactating dairy cows. At 32+/-3 d after pre-enrollment artificial insemination (AI; study d -7), 1 wk before pregnancy diagnosis, cows from 2 farms were enrolled and randomly assigned to 1 of 3 resynchronization protocols after balancing for parity, days in milk, and number of previous AI. All cows were examined for pregnancy at 39+/-3 d after pre-enrollment AI (study d 0). Cows enrolled as controls (n=386) diagnosed not pregnant were submitted to a resynchronization protocol (d 0-GnRH, d 7-PGF2alpha, and d 10-GnRH and AI) on the same day. Cows enrolled in the GGPG (GnRH-GnRH-PGF2alpha-GnRH) treatment (n=357) received a GnRH injection at enrollment (d -7) and if diagnosed not pregnant were submitted to the resynchronization protocol for control cows on d 0. Cows enrolled in CIDR treatment (n=316) diagnosed not pregnant received the resynchronization protocol described for control cows with addition of a controlled internal drug release (CIDR) insert containing progesterone (P4) from d 0 to 7. In a subgroup of cows, ovaries were scanned and blood was sampled for P4 concentration on d 0 and 7. After resynchronized AI, cows were diagnosed for pregnancy at 39+/-3 and 67+/-3 d (California herds) or 120+/-3 d (Arizona herds). Cows in the GGPG treatment had more corpora lutea than CIDR and control cows on d 0 (1.30+/-0.11, 1.05+/-0.11, and 1.05+/-0.11, respectively) and d 7 (1.41+/-0.14, 0.97+/-0.13, and 1.03+/-0.14, respectively). A greater percentage of GGPG cows ovulated to GnRH given on d 0 compared with CIDR and control cows (48.4, 29.6, and 36.6%, respectively), but CIDR and control did not differ. At 39+/-3 d after resynchronized AI, pregnancy per AI (P/AI) was increased in GGPG (33.6%) and CIDR (31.3%) cows compared with control (24.6%) cows. At 67 or 120+/-3 d after resynchronized AI, P/AI of GGPG and CIDR cows was increased compared with control cows (31.2, 29.5, and 22.1%, respectively). Presynchronizing the estrous cycle of lactating dairy cows with a GnRH 7 d before the start of the resynchronization protocol or use of a CIDR insert within the resynchronization protocol resulted in greater P/AI after resynchronized AI compared with control cows.

Endocrine alterations around the time of abortion in mares impregnated with donkey or horse semen.

The objective of this study was to monitor and compare the concentrations of equine chorionic gonadotropin (eCG), progesterone and estrone sulphate during normal and failed pregnancies of mares impregnated with donkey or horse semen, relating their individual endocrine profiles to the time of pregnancy loss, and to the histopathologic findings in the aborted fetuses and placenta. Mares (n=54) were used, 32 of them impregnated with donkey semen and 22 impregnated with horse semen. Blood samples were taken twice a week from Day 35 to 120 of pregnancy. Ultrasonographic observations of the fetus were carried out twice a week. The incidence of abortion in mares impregnated with donkey semen (30%) was greater (P<0.05) than the 5% observed in mares impregnated with horse semen. From Week 8 to the end of the sampling period, the mean progesterone concentrations of mares with normal mule pregnancies were less (P<0.05) than those of mares with normal pregnancies with equine fetuses. The concentrations of eCG were less (P<0.05) in mule pregnancies from Week 6. Estrone sulphate concentrations were only different (P<0.05) between types of pregnancy on Weeks 13 and 14, being in this case greater with the mule pregnancies. Most of the abortions of mule fetuses were associated with lesser progesterone concentrations than the average for mares with successful mule pregnancies. Four of the abortions of mule fetuses and the only abortion of horse fetus occurred in mares with lesser progesterone and very low eCG concentrations, and were classified as caused by luteal impairment secondary to eCG deficiency; estrone sulphate concentrations were less than normal or absent before these abortions. Two mares aborted after several weeks of low progesterone concentrations in the presence of eCG concentrations that were normal for mule pregnancies, suggesting primary luteal deficiency. In three mares carrying a mule fetus, the concentrations of progesterone and estrone sulphate decreased abruptly immediately before fetal death, suggesting luteolysis due to active prostaglandin F2 alpha (PGF2alpha) secretion. It is concluded that the greater incidence of abortion in mares impregnated by donkeys is associated with different kinds of luteal malfunction. Deficiency of eCG may be a primary cause of many of these cases, either by failing to stimulate enough luteal progesterone secretion and/or by failing to protect the corpora lutea (CL) of pregnancy from endogenous PGF2alpha secretion.

Reproductive performance of swine females re-serviced after return to estrus or abortion.

The objective of this study was to analyze reproductive performance in swine females re-serviced after return to estrus or abortion in comparison with females in first service (gilts or weaned females). Records used were obtained from four commercial sow herds in Brazil including 24,194 mating records from PigCHAMP research database. Three mating categories (first service in gilts or weaned sows, re-serviced after return to estrus and re-serviced after abortion) were considered for the analysis. The farrowing rate (FR) was less and return to estrus (RER), abortion rate (ABR) and total born (TB) were greater in the category re-serviced after return to estrus compared to first service category (P<0.05). The category re-serviced after abortion only differed from the first service category by a greater ABR (P<0.05). In gilts and PO2-5 females re-serviced after a return to estrus, the FR was less (72.0% and 83.2%) and RER was greater (22.3% and 12.5%) compared to first service PO2-5 sows (92.7% and 5.3%; P<0.05). A re-service after a return to estrus did not affect TB in PO > or =2 females (P>0.05) but resulted in less TB in gilts and greater TB in primiparous sows (P<0.05). In females re-serviced after a return to estrus the performance was similar (P>0.05) between the two intervals considered as regular return to estrus (18-24 days and 36-48 days). Among the intervals considered as irregular return to estrus, greater FR was observed in intermediate (25-35 days) than in early (11-17 days) or late (>48 days) intervals. The re-service after a return to estrus results in an impaired farrowing rate, with a greater impact on gilts than at older parities. Females re-serviced after abortion are more predisposed to the recurrence of this reproductive failure.

Immunopathology of Chlamydophila abortus infection in sheep and mice.

Chlamydophila abortus targets the placenta, causing tissue damage, inflammation and abortion (enzootic abortion of ewes). It is one of the main infectious causes of abortion in ewes, resulting in major economic losses to agricultural industries worldwide. Although ruminants and pigs are the principal hosts, humans are also susceptible to infection. Control of disease requires a host inflammatory response, which is likely to contribute to pathology and abortion. Mouse models have been widely used to provide insight into the role of specific immune cells in controlling infection and disease. The use of such model systems for investigating the mechanisms of abortion, latency, persistence, and immunity to reinfection will result in the identification of novel vaccine control strategies for sheep.

Effects of diet and body condition on fecal progestagen excretion in elk.

Recent research demonstrated the utility of fecal progestagens (P4) for detecting pregnancy in elk (Cervus elaphus) during mid- to late gestation. Several factors, however, may influence fecal P4 excretion and limit its use in free-ranging animals. We investigated the effects of nutrition and body condition (percent ingesta-free body fat) on fecal P4 concentrations and incidence of abortion. During mid-gestation (late December 1997 through early March 1998), 40 gravid cow elk varying in body condition were placed on three diets (high, medium, and low) in which the amount of food offered varied. Feces were collected periodically and analyzed for P4 via radioimmunoassay. We found no significant effect of dietary treatment on P4 concentrations, but as body condition declined, P4 concentrations declined significantly. This decline did not impede the ability to detect pregnancy based on previously reported criteria, even for elk in such poor condition that they aborted. However, fecal P4 concentrations in 10% (4/39) of samples collected from 13 non-pregnant animals maintained on a high plane of nutrition were false-positive for pregnancy. We suggest alternate criteria for determining pregnancy in elk using fecal P4 values: > 1.25 micrograms/g feces as pregnant, < 1.0 microgram/g feces as non-pregnant, and 1.0-1.25 micrograms/g feces as inconclusive. Finally, two cows that aborted did not abort until weeks after being classified as emaciated and near death, suggesting that nutrition-associated abortion in elk may not occur during mid-gestation except under extremely harsh conditions.

The effects of uncomplicated miscarriages and stillbirths on the ability of baboons to return to cyclicity and subsequently conceive.

Pregnant baboons are used regularly in medical research studies. Occasionally these studies have resulted in stillbirths and/or miscarriages. In addition, pregnant animals can spontaneously undergo stillbirths or miscarriages unrelated to any medical or research procedure. In the absence of identifiable inflammatory, infectious, or pathologic processes, it generally was assumed that these events had no bearing on the baboon's future ability to return to cyclicity and conceive. However, these assumptions were based on observational and anecdotal evidence. To test the validity of these assumptions, we established two data groups: baboons that had uncomplicated stillbirths (Gp-1; n = 11) and those that had uncomplicated miscarriages (Gp-2; n = 12). The mean number of days from first detectable postpartum estrus (i.e., perineal swelling/turgescence) to conception was 49 days for Gp-1 and 53 days for Gp-2. In addition, for Gp-1 animals we determined that the mean number of days to the first indication of estrus was 29 days; these data were unavailable for Gp-2 because of the lack of parturition as a reference point. Control baboons (lactating mothers) required approximately 59 days from first detectable estrus to conception, and our findings for Gp-1 and Gp-2 were consistent with this value. Therefore, within the limits of our study parameters, we suggest that uncomplicated stillbirth and miscarriage had no profound effects on a baboon's future ability to return to cyclicity and conceive.