Endometrial expression of key genes related to fertility in repeat breeder and non-repeat breeder cows

The aim of the present study was to compare the endometrial gene expression of epidermal growth factor receptor (EGFR), nodal growth differentiation factor (NODAL), prostaglandin-endoperoxide synthase 2 (PTGS2), oestrogen receptor 1 (ESR1) and progesterone receptor (PGR) in repeat breeder cows (RBC) and non-RBC during diestrus. Endometrial samples were collected by cytobrush technique and stored in RNA stabilizing solution at −20°C until RT-qPCR analysis. Differences in endometrial mRNA expression of selected genes were assessed by ANOVA and simple (r) and the partial correlations (rp) among selected genes were performed. Results demonstrated that mRNA expression of EGFR and NODAL were higher in RBC than in non-RBC (3 and 25-fold change, p < .01 and p < .01, respectively), while the mRNA expression of PTGS2 was lower (1.56-fold change, p < .01). Although there were no differences detected in the mRNA expression of ESR1 and PGR, there was a positive correlation between the expression of ESR1 and EGFR (0.84, p < .05) and a negative correlation between PGR and PTGS2 (−0.49, p < .05). In conclusion, the difference on the endometrial mRNA expression of the genes included in the study between RBC and non-RBC indicates a deregulation of important mechanisms that are vital to establish a successful pregnancy. Thus, the present study provides useful insight as a base for future studies to elucidate the causes of RBC.     

Cytological endometritis diagnosed at artificial insemination in repeat breeder dairy cows

This study aimed to (i) assess the prevalence of cytological endometritis (CYTO) diagnosed at artificial insemination (AI); (ii) evaluate the effect of CYTO on the pregnancy outcome of the same AI sample; and (iii) determine the risk factors associated with CYTO diagnosed at AI in repeat breeder (RB) dairy cows. We analysed the productive and reproductive performances of 146 RB Holstein‐Friesian cows. To obtain a CYTO sample at AI, we used the cytotape technique. Generalized mixed effect models were computed to find the risk factors associated with the pregnancy and CYTO outcome. Based on ≥1% PMN cut‐off point, the CYTO prevalence at AI in RB cows was 25.3%. The overall pregnancy at AI was 44.2%. The conception rate in CYTO‐positive (n = 37) RB cows was 29.7% versus 49.5% for CYTO‐negative (n = 109) cows. A RB cow diagnosed CYTO positive at AI had 0.47 [odds ratio (OR)] odds to become pregnant in comparison with a CYTO‐negative cow. Cows that produced more milk than their counterparts in this study had increased odds (OR = 1.01) to be CYTO positive at AI. A novel risk factor positively associated with CYTO diagnosed at AI in RB cows was the level of daily milk urea (OR = 1.11). To conclude, CYTO at the moment of AI had a significantly negative effect on the pregnancy outcome in RB dairy cows. However, as only one of fourth of RB cows is affected with CYTO at AI, it may not be considered a key element associated with the RB syndrome.     

Incidence and treatment of inadequate postovulatory progesterone concentrations in repeat breeder cows

The incidence of low day 5 milk progesterone in dairy cows has been investigated and the efficacy of treating the problem assessed. The incidence of inadequate milk progesterone (empirically defined as <3ng/mL) in repeat breeder cows was 34% compared with 11.4% in first insemination cows. Treatment with an intravaginal progesterone device for 7 days starting from day 5 or 6 did not improve pregnancy rate. Treatment with 1500 iu human chorionic gonadotrophin (hCG) on day 5 gave an increase in pregnancy rate that was dependent on initial progesterone concentration and significant (P<0.05) in multiparous but not primiparous cows. While the incidence of inadequate day 5 progesterone was high in repeat breeder cows, it was responsive to hCG treatment, although only in multiparous and not primiparous animals.     

产蛋期肉种鸡脂肪肝综合征的诊治

某场饲养的9500套肉种鸡在产蛋上高峰期间,其中一栋鸡舍鸡只发病并死亡,经检测诊断为鸡脂肪肝综合征。现将诊治情况介绍如下：     

Reciprocal embryo transfer between repeat breeder and virgin heifers--an experimental model

The aim of the study was to evaluate the importance of mother-concaptus relationships for the elevated embryonic loss in repeat breeder heifers. Embryos were collected by non-surgical technique, classified and transferred surgically or non-surgically to synchronized, inseminated recipients. The embryos were transferred to the uterinehorn contralateral to the corpus luteum. The embryos were transferred from repeat breeder heifers (RBH) to virgin heifers (VH) or from VH to RBH. After slaughter 4 weeks after transfer there was no difference in emhryonic survival between heifer categories following transfer or insemination. In some animals degenerated foetal membranes were found in the nonpregnant horn. The study indicates embryonic morphology rather than the category of donor or recipient as influencing the embryonic survival rate.Key words: embryo, embryonic death, embryo transfer, repeat breeder     

Nonsystemic causes of the downer cow syndrome

Traditionally, the downer cow has been considered a metabolic problem. This viewpoint cannot account for the pelvic limb predilection of the condition. Whatever the primary cause of recumbency, all recumbent animals are susceptible to pressure damage. The extensive literature on pressure damage in human beings and horses is reviewed. Miscellaneous causes of and contributing factors to bovine recumbency are reviewed. Concepts and details of diagnosis, prevention, management, and therapy are discussed.     

Treatment and control of an outbreak of fat cow syndrome in a large dairy herd

An outbreak of fat cow syndrome occurred in a herd of 300 Friesian and Friesian/Holstein dairy cows calving predominantly between January and May. The herd came in off grass in good condition despite a long and hot summer. The dry cows received a diet of grass silage, brewing waste and minerals until the end of December, but the grass silage was butyric and was partially replaced by maize silage. By January 23, 16 of 70 calving cows (23 per cent) had appeared to suffer milk fever. Subsequent blood tests revealed that the cows may have been ketotic, and clinical and post mortem examination showed that they were probably suffering from fat cow syndrome. The freshly calved sick cows were treated with glucose, and corticosteroids were injected every second day into those which remained ill. The cattle had received a high energy diet, but the cows still to calve were placed on a diet of low metabolisable energy (77 MJ/cow) but adequate levels of undegradable protein. The problem was associated with a possible clostridial infection in two cows and with reduced fertility.     

Factor XI mutation in a Holstein cow with repeat breeding in Japan

Factor XI deficiency is an autosomal recessive coagulopathy in Holstein cattle. Affected cows have a tendency to show repeat breeding. Forty repeat breeding Holstein Friesian cows were selected and tested for the Factor XI mutation. Genomic DNA was isolated from the blood of the cows (n=40). Exon 12 of the Factor XI gene of the cows was amplified by PCR. One repeat breeding cow was heterozygous to the Factor XI mutation as indicated by the presence of two DNA fragments of 320 bp and 244 bp. The insertion of the 76 bp in the heterozygous cow was confirmed by DNA sequencing. The heterozygous cow was in her fourth lactation. She gave birth to male twins at the last calving. She was inseminated artificially four times after the last calving. Factor XI deficiency in cattle has been reported in different countries. However, no case was reported in Japan. This might be the first to report Factor XI mutation in Holstein cattle in Japan.     

Successful,repeated non-surgical collection of blastocysts from virgin and repeat breeder heifers

A total of 55 non-surgical collections, 7 days after spontaneous heat, was made in 19 heifers. Recovery rate was 57% (17/30) from 10 repeat breeder heifers and 72% (18/25) from 9 virgin heifers, this difference was not significant. Fertilization rate in both groups was 94%. The eggs were always recovered in the first 100 ml of flushing medium. Mean lengths of oestrous cycle after non-surgical collection were, respectively, 16.9 and 18.1 days in repeat breeder and virgin heifers. This difference was not significant. However, the cycle in which the first collection was made was significantly shorter (P<.005) than the cycle immediately before the collections. Only 61% of possible eggs were non-surgically collected from 4 superovulated repeat breeder cows and no further eggs were found after slaughter, one to two hours later.