Predisposing factors,diagnostic and therapeutic aspects of persistent endometritis in postpartum cows

A certain level of endometrial bacterial infection and inflammation is involved in bovine uterine involution during the puerperal period. Factors that hamper normal uterine involution expose the uterine environment to pathological conditions, causing different endometritis levels. The lack of proper diagnostic tools extends the time to conception. Efforts have been made to elucidate the postpartum uterine environment, including bacterial flora, changes in transient endometrial inflammation, and the pathophysiology of endometritis, to improve bovine reproductive performance. E. coli and Trueperella pyogenes in the uterus are likely to cause persistent infection, and Mycoplasma bovigenitalium infection is associated with dystocia and cytological endometritis in postpartum dairy cows. Due to the widespread use of cytobrush as a diagnostic tool for bovine subclinical endometritis (SE) that enables quantification of the degree of inflammation, we found that endometritis at week 5 postpartum was associated with delayed first ovulation. Approximately 30% of open cows have SE during the postpartum period, and cows with low blood glucose during prepartum have a high risk of developing SE. Additionally, cows with purulent vaginal discharge do not always have endometritis but only vaginitis and/or cervicitis. Intrauterine infusion of polyvinylpyrrolidone-iodine (PVP-I) improves fertility and promotes endometrial epithelial cell regeneration after inducing transient uterine inflammation, suggesting that PVP-I could be a good alternative to antibiotics. In conclusion, prepartum management to prevent glucose deficiency, prompt diagnosis to identify causative agents and intrauterine inflammation levels, and appropriate treatment to minimize antimicrobial resistance is beneficial for tackling endometritis and improving reproductive performance in bovine herds.     

Influence of Puerperal Uterine Infection on Uterine Involution and Postpartum Ovarian Activity in Dairy Cows

This article presents the results of a clinical trial designed to study the effect of puerperal uterine infection on uterine involution and on ovarian activity in dairy cows, monitored twice weekly from parturition until the sixth week postpartum (wpp). Infection significantly retarded uterine involution assessed by the uterine body diameter and a score of intrauterine fluid volume (IUFV). By the sixth wpp, cows with normal puerperium (controls) and cows that showed mild puerperal endometritis had similar uterine body diameter and IUFV, indicating spontaneous recovery within the postpartum voluntary waiting period. However, in cows with severe puerperal endometritis, although uterine body diameter had regressed to pregravid size, IUFV remained significantly higher than in control and mild endometritis cows, indicating that chronic endometritis was established. The IUFV score was positively and significantly correlated with uterine swab bacterial growth density and allowed diagnosis of endometritis after the third wpp. Cows with mild or severe endometritis had a significantly higher prevalence and persistence of pathogenic bacteria ( Escherichia coli , Actinomyces pyogenes , Gram-negative anaerobes – GNA) than controls. Actinomyces pyogenes was associated to GNA in 74% of isolations. Ovarian activity measured by ultrasound scanning of the ovaries and plasma progesterone (P4) concentrations was more abnormal (prolonged anoestrus, prolonged luteal phases and ovarian cysts) in cows with severe endometritis than in controls.     

Combined GnRH and PGF2α Application in Cows with Endometritis Puerperalis Treated with Antibiotics

The investigations were carried out on a total of 70 cows with puerperal endometritis. In addition to intrauterine antibiotic treatment, 30 experimental animals were administered 20 μg GnRH analogue, buserelin, between days 10 and 12 post‐partum followed by 500 μg PGF_2α analogue, cloprostenol, 10 days later. Forty control cows were treated only with intrauterine antibiotics. Blood samples for progesterone determination were collected from the tail vein twice weekly until day 70 post‐partum. The first rise in progesterone level above 3.18 nmol/l occurred significantly earlier in the experimental than in control cows (21.6 ± 9.2 versus 27.8 ± 12.3 days; p ≤ 0.05). The duration of the first cycle post‐partum was 15.0 ± 4.3 days in experimental and 19.7 ± 7.3 days in control animals (p ≤ 0.05). However, no significant differences were observed in the occurrence of first oestrus post‐partum. The involution of the uterus was improved after hormone treatment. At day 42 post‐partum, completion of uterine involution was found in 93.3% of hormone‐treated cows and in 82.5% of those treated with antibiotic only (p ≤ 0.05). Clinical recovery was 96.6% in the experimental and 82.5% in the control group (p ≤ 0.05). First service pregnancy rate was significantly better in hormone‐treated than control cows (51.7 versus 36.4%; p ≤ 0.05). Total pregnancy rate and insemination index values were not significantly improved following GnRH and PGF_2α treatment. The average service period was 89.8 ± 21.2 days in cows after hormone treatment, and 112.6 ± 24.5 days in control cows. The difference was statistically significant (p ≤ 0.05). These results indicate, that the sequential GnRH and PGF_2α application in cows with puerperal endometritis positively affected ovarian function and uterine involution, resulting in improved fertility performance.     

Significance of nitric oxide concentration in plasma and uterine secretes with puerperal endometritis in dairy cows

Endometritis is an inflammation of the endometrial lining of the uterus without systemic signs, which is associated with chronic postpartum infection of the uterus with pathogenic bacteria. Nitric oxide (NO) is an inflammatory mediator that among other effects causes smooth muscle relaxation and mediated cytoimmunity and inflammation toxicity. To see if the nitric oxide concentration in plasma and uterine secrets is related with postpartum endometritis, NO concentrations in plasma and uterine secrets were measured in dairy cows with puerperal endometritis (clinical endometritis (n = 60) and subclinical endometritis (n = 58)). Cows with clinical or subclinical endometritis showed higher concentrations of NO in both plasma and uterine secrets when compared with normal cows and the highest concentrations of NO in plasma and uterine secrets were found in dairy cows with clinical endometritis. Expression level of NOS2 mRNA in endometrial biopsies from cows with puerperal endometritis was also higher and the highest expression of NOS2 mRNA was found in cows with clinical endometritis. The results showed that concentrations of NO in plasma and uterine fluid are related with the degree of endometritis which may be useful to diagnose the endometritis in dairy cows.     

Incidence of subclinical endometritis and its effects on reproductive performance of crossbred dairy cows

In dairy cattle, uterine infections are not life threatening and often unavoidable; however, they reduce fertility and increase the production costs of properties. The aim of this study was to evaluate the incidence of subclinical endometritis from 32 to 70 days in milk (DIM) and its effects on the reproductive performance of crossbred dairy cows. Lactating cows (Holstein/Gir; n?=?172), with no history of retained placenta, without clinical signs of uterine infection were used. The body condition score (BCS) was evaluated on a scale from 1 to 5. Ultrasound examination was performed to evaluate uterine lining and ovarian activity, while vaginal mucus was analyzed by gloved hand. The diagnosis of subclinical endometritis was performed by endometrial cytobrush technique. The samples were collected, stained, and examined microscopically; positive cases for subclinical endometritis were considered with the presence of ≥5 % of neutrophils. Later, the cows were submitted to conventional artificial insemination or timed artificial insemination. The incidence of subclinical endometritis in the herd was 26 %, and this was not affected by the season of calving, presence of corpus luteum, DIM, and parity. Cows with a BCS ≤2.50 had a higher incidence of subclinical endometritis. The conception rate to first insemination and pregnancy rate at 150 days postpartum were not influenced by the presence of subclinical endometritis in crossbred dairy cows.     

奶牛子宫内膜炎诊疗学研究进展

子宫内膜炎是奶牛产后普遍发生的一种生殖疾病,可导致奶牛产犊间期延长、产奶量降低、淘汰率增加、治疗期间奶源废弃、管理及治疗成本增加,也是导致奶牛不孕症的重要原因之一。目前国内外防治奶牛子宫内膜炎的诊断技术和治疗方法众多,主要有阴道镜检查、Metricheck装置评估、子宫细胞学检查、抗生素疗法、中药疗法、中西医结合疗法、激素疗法、臭氧新型疗法等诊疗技术。阴道镜检查是一种可视化检查方法,利用内窥镜直观评估奶牛阴道内分泌物性状确定子宫内膜炎严重程度;Metricheck装置是根据阴道内分泌物含量和性状,设置不同评分值评估产后奶牛子宫内膜炎和繁殖性能;子宫细胞学检查通过子宫细胞刷、灌洗或活检技术确定子宫内膜细胞和中性粒细胞（PMN）的比例,设定奶牛产后不同时期PMN最佳阈值诊断子宫内膜炎;抗生素疗法通过宫内灌注、皮下注射、静脉注射抗生素等途径治疗奶牛子宫内膜炎,治疗成本低,见效快,是目前治疗奶牛临床子宫内膜炎最常用的疗法;中药疗法筛选不同组分的中药复方制剂,通过调节奶牛机体免疫系统,改善子宫内血液循环,抑制致病菌繁殖,促进子宫恢复正常生理机能;中西医结合疗法兼具中药辩证治疗的优点和西药见效快的特点,临床治疗奶牛子宫内膜炎具有广泛应用价值;激素疗法中前列腺素通过诱导黄体溶解,消除黄体酮产生和免疫抑制,刺激子宫复旧,降低产后奶牛长期子宫感染和炎症的风险;臭氧新型疗法是将臭氧制作成泡沫制剂、油制剂等产品通过宫内灌注杀灭病原菌。这些诊疗技术在治疗奶牛子宫内膜炎的过程中均取得了不同程度的效果,对评估产后奶牛繁殖性能和生产性能具有良好的指导作用。文章通过介绍这些诊疗技术在奶牛子宫内膜炎中应用的研究进展,以期为该病的防治提供参考。     

Effect of beta-carotin serum concentration on the reproductive performance in dairy cows

The aim of the following investigation was to study the effect of beta-carotin serum concentrations on reproductive performance in dairy cows. Blood samples were collected from 201 cows 3 to 4 weeks antepartum, 1 to 2 weeks postpartum and at the time of insemination. Concentrations of beta-carotin in blood serum were determined via HPLC. The incidence of retained placental fetal membranes, endometritis, ovarian cysts as well as the beginning of the oestrous cycle and various measures of fertility such as first service conception rate, pregnancy index, interval from calving to first insemination, interval from calving to conception, interval from first insemination to conception and expected calving interval were recorded and analysed. The beta-carotin serum concentrations were not related to the incidence of retained placental fetal membranes, endometritis, ovarian cysts or the onset of cyclicity post partum. Cows with lower beta-carotin concentrations partially seemed to have a reduced reproductive performance than cows with higher beta-carotin concentrations. Overall, our results suggest only a minor relationship between the beta-carotin serum concentration and fertility in dairy cows.     

Hormonal treatments for fertility disorders in cattle

In dairy cows, hormonal treatments are commonly implemented for acyclicity, silent heat and endometritis. Before treatment, causes of infertility need to be detected and severe failures in housing, feeding or other diseases must be eliminated. Without sustainable improvement of herd management, the use of intensive hormonal treatments will not improve reproductive performance. The most common cause of anoestrous is silent heat. In cows with a palpable corpus luteum, injection of prostaglandin F2α (PGF) reliably induces oestrous. A satisfactory treatment for acyclicity (ovarian dystrophy, ovarian cysts) does not exist. Combinations of different hormones have greater treatment success than a single use of gonadotrophin releasing hormone (GnRH) or human chorionic gonadotrophin (hCG). Strategic use of PGF during the early postpartum period cannot be recommended because positive effects on uterus involution and resumption of the oestrous cycle after calving have not been verified. In contrast, application of GnRH combined with PGF in the puerperal phase appeared to have positive effects on fertility of cows with endometritis. The same applies to PGF for cows with chronic endometritis. Cases of endometritis with fetid odour of vaginal mucus or isolation of Trueperella pyogenes should be treated with antibiotics. Treatment before the 27th day post partum is not advisable. In conclusion, hormonal treatments can be used to treat fertility disorders. Nevertheless, in order to enhance the reproductive performance at the herd level, a sustainable improvement of the general conditions (housing, feeding, animal health, management) is a prerequisite.     

Development of a Multiplex PCR for the Identification of Major Pathogenic Bacteria of Post‐Partum Endometritis in Dairy Cows

Post‐partum period has an important role in cows' breeding due to its effects on reproductive efficiency and subsequent pregnancy. Escherichia coli, Trueperella pyogenes (Arcanobacterium pyogenes), Fusobacterium necrophorum and Prevotella melaninogenicus are recognized as major pathogens associated with uterine endometrial lesions. The objective of this study was to identify these pathogens using the polymerase chain reaction (PCR) as a culture‐independent sensitive method. A total of 172 cows were examined 25–35 days post‐partum, and 128 cows were examined at 2 weeks later (39–49 days post‐partum). Uterine discharges were collected by covered plastic infusion pipettes. The prevalence of endometritis was greater in the first examination than the second (35.5% vs. 16%). E. coli was detected in eight of the samples, T. pyogenes was detected in 13 of the samples and F. necrophorum was detected in 11 of the samples. There was no positive sample of P. melaninogenicus. Uterine contamination by T. pyogenes and F. necrophorum in the first examination was higher than the second examination. T. pyogenes affected as a tendency the prevalence of clinical endometritis in first examination. Primiparous cows showed 4.02 times higher odds of clinical endometritis compared with second‐parity cows in first examination. A multiplex PCR protocol as a simple, less expensive, fast assay was introduced to identify E. coli, T. pyogenes and F. necrophorum.     

Estimating prevalence of endometritis in smallholder zero-grazed dairy cows in Rwanda

Endometritis is a postpartum uterine disease of cows that interrupts reproductive cycles resulting in suboptimal fertility, reduced performance and profitability of the dairy herd. The objective of the study was to estimate the perceived and observed prevalence of endometritis among zero-grazed dairy cows in smallholder farms in Rwanda. A snowball sampling method was applied in cross-sectional survey to obtain data from 370 farms on 466 cows within their 21–60 days postpartum (dpp). The survey, conducted from September 2018 to March 2019, simultaneously examined cows using the Metricheck Device (MED) to determine the presence and type of vaginal mucus (VMC) based on a score scale of 0 to 3. Cows scoring VMC ≥ 1 were recorded as clinical endometritis (CLE)–positive. Cytotape (CYT) was used to determine the percentages of polymorphonuclear cells (PMN) in endometrial cytology sample. Cows with ≥ 5% PMN were recorded subclinical endometritis (SCLE)–positive, whereas cows with VMC-0 and < 5% PMN were considered healthy cows. At cow-level, endometritis prevalence was 70.2% with 67.2% CLE and 31.8% SCLE while at the herd-level, prevalence was 71.1% with 68.1% CLE and 34.4% SCLE. The differences between the diagnostic performance of the MED and CYT were significant (p < 0.001). Perceived prevalence by farmers was much lower (3.2%) and without agreement with the observed prevalence (kappa = − 0.02, p > 0.05). The highly observed prevalence and farmer underestimation of endometritis prevalence indicate knowledge gaps about endometritis. The extension service therefore needs to increase awareness and education among smallholder farmers about detection and management of endometritis.

     

Clinical and Bacteriological Aspects on the Use of Oxytetracycline and Flunixin in Primiparous Cows with Induced Retained Placenta and Post-partal Endometritis

Retention of the fetal membranes and post‐partal endometritis (RFM) are common problems in dairy cows. Treatment often includes manual removal of the placenta in combination with antibiotic treatment. Earlier studies have shown that cows with endometritis post‐partum have a strong tendency to recover spontaneously. The present study focused on treatments of post‐partal endometritis with the prostaglandin synthesis inhibitor, flunixin (F) either alone or combined with oxytetracycline (T). The study was conducted in two experiments, using 12 primiparous cows in each. As a model for RFM, premature parturition was induced in late pregnant heifers by injecting PGF_2α (25 mg i.m.) twice with a 24 h interval. In each experiment the cows were set into four groups and treated with either T (10 mg/kg BW i.m. once daily), F (2.2 mg/kg BW p.o. twice daily), a combination of T and F (dosage, as above) or conservatively (group 0, no drugs). The treatment periods lasted from days 11–14 post‐partum in experiment 1 (groups T1, F1, TF1 and 0) and from days 3–6 post‐partum in experiment 2 (groups T2, F2, TF2 and 0). Jugular vein blood samples were collected for analyses of flunixin and total white blood cells. Uterine biopsies were collected twice weekly for investigation of endometrial microbiology. Rectal palpation and ultrasonographic examinations were performed three times weekly for investigations of uterine involution and ovarian activity. No attempts were made to remove the placentas manually. The experiment lasted until day 56 post‐partum. The induction of parturition was successful in all heifers and 22 of 24 animals had RFM. All RFM cows had bacterial endometritis. The predominant bacteria were Escherichia coliα‐haemolytic streptococci, Fusobacterium necrophorum, Arcanobacterium (Actinomyces) pyogenes, Bacteroides spp., Pasteurella spp. and Proteus spp. Fusobacterium necrophorum and A. pyogenes could be isolated for 3–5 weeks post‐partum and E. coli, Pasteurella and Proteus could be isolated for 2–3 weeks post‐partum. Animals treated with tetracycline after placental shedding (T1 and TF1) had a more rapid recovery from infections with A. pyogenes and F. necrophorum than animals that were not treated with tetracycline. No other genera were affected. Antibiotic treatment before placental shedding (T2 and TF2) did not shorten the uterine infection but altered the bacterial flora, seen as an overgrowth of Proteus spp. (p < 0.05) and increased frequency of Pasteurella (p < 0.05). The α‐haemolytic streptococci were less common in T2 and TF2 than in other groups (NS). Antibiotic treatment of cows before placental shedding (T2 or TF2, n=6) postponed detachment of placenta compared to cows were no antibiotics were administered before placental shedding (T1, TF1, F1, F2 and 0, n=16, 9.8 days pp (median) versus 11.8, p=0.004). Neither treatment shortened uterine involution. Flunixin treatments did not seem to influence recovery from infection or uterine involution. It was concluded that early oxytetracycline treatment of retained fetal membranes in the cow did not shorten the uterine involution or uterine infection but it did slow down the detachment process of the retained placenta. Oxytetracycline treatment after placental shedding might shorten the uterine infection but otherwise did not affect the clinical results. Flunixin treatment had no influence on the clinical outcome of the disease.     

奶牛产后子宫感染与子宫免疫

非特异性子宫感染会降低奶牛的生产性能和奶牛场的潜在效益。发生子宫感染时常并发感染化脓性放线杆菌或混合感染其他细菌。当从产后21 d的奶牛子宫液中分离到化脓性放线杆菌时,说明奶牛发生了严重的子宫内膜炎,并且将导致产后第一个发情期不孕。然而引起子宫感染的确切原因尚不清楚,但可以肯定与多种因素有关。发生难产、胎衣不下、怀有双胎或死胎以及患有各种代谢紊乱疾病的奶牛比其他奶牛更容易发生子宫感染。分娩前后异常的免疫功能更容易导致发生严重的子宫感染。子宫感染一般不会引起奶牛死亡,但是发生子宫感染的奶牛其生产性能会受到很大影响。另外,子宫发生感染还会降低产奶量,并且对子宫感染的一些治疗措施还会对牛奶产生污染。因为感染的非特异性,所以子宫感染很难预防;注意加强卫生设施以及围产期的卫生,特别是在助产过程中的卫生,才可能是最好的预防方法。异常免疫功能导致奶牛发生子宫感染的现象,说明通过对免疫功能的调节来预防和治疗围产期奶牛子宫感染是有潜力的。     

Mechanisms of Infertility Associated with Clinical and Subclinical Endometritis in High Producing Dairy Cattle

Clinical and subclinical endometritis are common causes of infertility and subfertility in high producing dairy cattle, delaying the onset of ovarian cyclic activity after parturition, extending luteal phases and reducing conception rates. Escherichia coli and Arcanobacterium pyogenes cause endometrial damage and inflammation. Components of microbes, such as lipopolysaccharide (LPS), are detected by Toll-like receptors on endometrial cells, leading to secretion of cytokines, chemokines and antimicrobial peptides. Long luteal phases associated with endometritis are probably caused by a switch in endometrial prostaglandin production from prostaglandin F_2a (PGF) to prostaglandin E₂. In addition, LPS impairs the function of the hypothalamus and pituitary, and directly perturbs ovarian granulosa cells steroidogenesis, providing mechanisms to explain the association between uterine disease and anovulatory anoestrus. Cows with uterine disease that ovulate have lower peripheral plasma progesterone concentrations that may further reduce the chance of conception associated with endometritis.     

Relationship between milk somatic cell count and postpartum ovarian cyclicity and fertility in dairy cows

The main objective of the study was to describe the relationship of high somatic cell count (SCC) with the incidence of abnormal postpartum resumption of ovarian cyclicity and reproductive performance in dairy cows. The factors influencing SCC were also investigated. Four hundred and forty-seven cows from six dairy herds in Japan were monitored for SCC and postpartum resumption of ovarian cyclicity. Cows with high SCC (200,000 to 500,000) had a higher incidence of prolonged luteal phase (P < 0.01) than cows with an SCC of 50,000 to 100,000. The high SCC cows (> 500,000) also showed a higher incidence of delayed first ovulation post partum than cows with an SCC ≤500,000 (P < 0.05) during the first month post partum. Cows with an SCC of 200,000 to 500,000 showed lower conception and pregnancy rates, and more days from calving to conception than cows with an SCC of less than 200,000 (P < 0.05). Cows in parity 5 or more had a higher incidence of high SCC than cows in the first and second parities (P < 0.05). It is concluded that cows with a high SCC have a higher incidence of abnormal postpartum resumption of ovarian cyclicity, leading to reduced reproductive performance.     

Evaluation of the diagnosis of subclinical endometritis in dairy cattle using ultrasound

The aim of this study was to determine signs of subclinical endometritis found by ultrasound that are associated with reduced fertility in dairy cows.The maximum diameter of the uterine lumen was determined by ultrasound in 324 cows without clinical signs of endometritis after evaluation of the genital tract 21 to 27 days postpartum. Cows were classified into healthy or with subclinical endometritis by three threshold values for the maximum uterine lumen diameter of 0.2 cm, 0.5 cm or 0.8 cm. Examinations by rectal palpation and ultrasound as well as classifications were repeated 14 days later. In addition, ovaries were scanned by ultrasound to determine the stage of the estrous cycle. In a subgroup of 103 cows the echotexture of the uterus and its contents was evaluated. In these cows the diagnosis of subclinical endometritis was performed by a scoring system. The diameter of the uterine lumen was significantly affected by stage of the estrous cycle at the time of examination. However, no effects were found for the stage of the cycle at the time of examination on subsequent reproductive performance. A uterine lumen with a maximum diameter of more than 0.2 cm showed a significant negative association with conception rate and proportion of cows pregnant. Classification based on higher threshold values did not reveal an association with reproductive performance. Echogenic content in the uterus also decreased reproductive performance. A classification based on the echotexture of the uterus and its contents revealed significant differences between healthy cows and cows with subclinical endometritis regarding the proportion of cows inseminated and pregnant.The results of this study showed that the diagnostic of bovine endometritis should be broadend by ultrasonography. The definition of subclinical endometritis diagnosed by means of ultrasonography has to be evaluated in further studies.     

Reproductive efficiency of cows with endometritis after treatment with intrauterine infusions or prostaglandin injections, or no treatment

Data from 3276 cows with 6598 lactations in 85 herds participating in a herd health monitoring programme were selected for an observational study. Cases of endometritis were diagnosed based on a clinical examination after 21 days postpartum. The cases were grouped by the severity of endometritis (mild, severe) and by the treatment performed (intrauterine infusion, prostaglandin injection, no treatment). The conception rates and the calving-to-conception intervals of these groups were compared statistically. Conception rate was lower in cows with severe endometritis compared to cows with mild endometritis while it did not differ between treatment groups. In cows with mild endometritis a significantly longer calving-to-conception interval was observed if intrauterine infusions were performed compared to the other two treatment options. The occurrence of other fertility problems during the same service period had a significant effect on conception rate and calving-to-conception intervals. In cows with severe endometritis intrauterine or prostaglandin treatments appeared to be beneficial, whereas intrauterine infusions in cows with slight endometritis had a negative effect on reproductive efficiency.     

Relationships between body weight and milk yield during the early postpartum period and bull and technician and the reproductive performance of high producing dairy cows

The aim of this study was to evaluate the effect of body weight (BW) change during the early postpartum period and BW on day 50 post partum on the subsequent expression of estrus and fertility at first insemination before day 90 post partum. The data were derived from 1036 postpartum cows reaching 90 days in milk. The following data were recorded for each animal: lactation number, daily milk production at day 50 post partum, calving date, days in milk at estrus and at AI, insemination date, insemination number, inseminating bull, AI technician and body weight at calving, at day 50 post partum and at AI. Of the 1036 cows registered, 817 (78.9%) showed first estrus before day 90 post partum and were inseminated. Using logistic regression procedures and based on the odds ratio a one unit (kg) increase in the daily milk production at day 50 post partum and a one unit (kg) decrease in the BW between calving and day 50 post partum were related to a 1.03-fold increase and a 0.97-fold decrease in the estrus expression rate before day 90 post partum, respectively. Of the 817 cows inseminated before day 90 post partum, 437 became pregnant (53.5%). A one unit increase in the BW at day 50 post partum produced a 1.003-fold increase in the early fertility rate. Pregnancy rate before day 90 was also influenced by the season at calving, bull providing semen and technician. In conclusion, the register of BW during the postpartum period may be a useful tool for evaluating the nutritional status and its relationship with the subsequent reproductive efficiency in dairy cows.     

重组溶葡萄球菌酶对奶牛子宫内膜炎的疗效研究

为研究重组溶葡萄球菌酶对奶牛子宫内膜炎的疗效,以青霉素钠、土霉素为对照药物,子宫内灌注给药,分别在河北、内蒙古、广州、上海奶牛场试验,共治疗急、慢性子宫内膜炎病例359头,抽检249头奶牛子宫分泌物进行细菌学分离鉴定与统计分析。结果表明,大肠杆菌、金黄色葡萄球菌、链球菌、化脓棒状杆菌是4种检出率较高的病原菌。重组溶葡萄球菌酶治疗组与土霉素、青霉素钠比较,按400、800、1200U／次的三个浓度剂量治疗,隔日投药1次,连续用药3次,800、1200U／次的浓度剂量显效率超过80％,显著优于青霉素钠的疗效（P〈0．01）,与土霉素注射液组相当。追加用药次数可进一步提高奶牛子宫内膜炎的痊愈率。重组溶葡萄球菌酶能有效治疗由金黄色葡菌球菌、链球菌、化脓棒状杆菌等革兰氏阳性菌感染的子宫内膜炎,治愈后受孕率在70％左右。尤其是对抗生素治疗无效的慢性子宫内膜炎同样具有很好的疗效。因此,用重组溶葡萄球菌酶治疗奶牛子宫内膜炎安全、高效。     

Subclinical endometritis in dairy cattle and its effect on fertility--a review of recent publications

Reduced reproductive performance in dairy cattle is often caused by uterine disorders. Beside acute metritis and chronic endometritis recent reports on a negative impact of subclinical endometritis on reproductive performance have been published. Diagnosis of subclinical endometritis can be performed by ultrasonography or cytological examination of the uterus. The cytological examination is based on uterine lavage or the cytobrush-method. Prevalence of subclinical endometritis in different studies ranges from 16 to 90 percent and depends on the diagnostic method and the time postpartum when the examination is performed. Affected cows showed significantly decreased conception rates, prolonged days to first service and days open as well as a reduced number of cows pregnant. Studies on the treatment of subclinical endometritis with prostaglandin F2alpha or analogues, intrauterine antibiotics or proteolytic enzymes showed heterogeneous results and do not allows valid recommendations for veterinary practice.     

Targeted transcript analysis revealed association of suboptimal expression of certain endometrial immunity-related genes with disparate uterine diseases in zebu cows

The onset of uterine infection during postpartum period compromises uterine health, fertility, and productivity of dairy cattle. Endometrial innate immunity plays a key role in eliminating uterine infection and keeping the uterus healthy. Hence, the present study has been designed with the hypothesis that altered endometrial immune response around calving may compromise uterine health during postpartum period. Expression of interleukins (IL-1β, IL-6, IL-8, IL-10, and TNF-α), prostaglandin synthase (PGFS, PGES), and antimicrobial peptides (beta-defensins (BDEF-4, BDEF-5), lingual antimicrobial peptide (LAP), and calcium-binding proteins (S100A8, S100A9, and S100A12) in endometrial tissues on the day of calving was studied using qRT-PCR, and circulating concentrations of prostaglandin E and F metabolites (PGEM and PGFM) during peripartum period (on days ??7, ??4, ??1 (before calving), 0 (on the day of calving), +?1, +?4, and +?7 (post calving)) of normal (healthy) cows (n?=?11) that did not develop postpartum uterine infection and cows that developed puerperal metritis (n?=?7) and clinical endometritis (n?=?6) were studied. Endometrial expression of IL-1β, TNF-α, BDEF-4, BDEF-5, S100A8, S100A12, and PGFS was higher (P?<?0.05), and expression of IL-6, IL-8, IL-10, and PGES was lower (P?<?0.05) in normal (healthy) cows than puerperal metritic and clinical endometritic cows. The PGFM concentration in serum was high (P?<?0.05) on days 0, +?1, and +?4 of calving in puerperal metritic cows followed by normal and clinical endometritic cows. However, PGEM concentration in serum was high (P?<?0.05) during peripartum period in uterine-infected (puerperal metritic and clinical endometritic) cows compared with normal cows. From the above findings, it is concluded that higher constitutive expression of IL-1β, TNF-α, PGFS, BDEF-4, BDEF-5, S100A8, and S100A12 genes in the endometrium and lower concentration of PGEM during the period immediate to calving might be beneficial for uterine health of cows.