Cytological, Bacteriological and Antibiogram Studies for the Management of Uterine Infection in Repeat Breeder Bovines

Background: Repeat breeding syndrome (RBS) associated with sub-clinical uterine infection (UI) remains to be a major reproductive problem faced by Indian farmers. Present study documents its diagnosis, prevalent etiological agents, antibiogram pattern and efficacy of the treatment at field level. Methods: Seventy-eight RBS affected bovines were selected. The cervical mucous (CM) was collected for study of its characteristics, white-side test, endometrial cytology, microbial examination and antibiogram. The treatment protocol was developed and the animals’ response to the treatment was assessed. Result: The overall incidence of RBS was found to be 12.9% and the cases associated with uterine infection (RBS/UI+ve) and without uterine infection (RBS/UI-ve) were 44.87% and 55.13%, respectively. The mean scores of CM character, odour, pH and number of polymorphonuclear cells in RBS/UI +ve were 2.09±1.39, 1.14±0.12, 8.49±0.08 and 12.46±0.96, respectively, and differed significantly (P less than 0.05) from RBS/UI-ve cases. The microbial examination revealed the presence of gram negative bacilli, Trueperella spp., Pseudomonas spp., Staphylococcus spp., Escherichia coli and yeast infection. Antibiogram studies recorded the response of Tetracyclin as best (48.57%) followed by Cephalexin (22.86%), Chloramphenicol (20.0%) and Streptomycin (8.57%). The RBS/UI+ve cases were treated individually, on one-to-one basis, obeying antibiogram. The infection appeared to be considerably controlled and overall success rate was observed in the form of confirmed pregnancy in 71.43% cases. Thus, it was concluded that prompt diagnosis using endometrial cytology and antibiogram guided therapeutic approach may aid for effective management of RBS/UI +ve cases, under field conditions.

Increased Number of Corpora Lutea by Creating Additional Corpus Luteum Leads to Enhanced Progesterone Concentrations and Improved Fertility in Bovine Repeat-breeder Females Undergoing the Short-term Fixed-time Artificial Insemination Protocol

Background: Lower concentrations of endogenous progesterone (P) after fertilization, due to corpus luteum (CL) dysfunction, leads to an increased embryonic loss and reduced pregnancy outcomes not only in female cattle but also in women. Therefore, an increase in the number of corpora lutea (CLs) may improve fertility in infertile bovine females. The aim of the current study was to investigate the influence of increased number of CLs by creating accessory CL on plasma P concentration and fertility in bovine repeat-breeder females undergoing the short-term fixed-time artificial insemination (FTAI) protocol.Methods: In experiment 1, 32 female cattle had induced ovulation with the short-term (5-day) P-based protocol. To induce additional CL, cows were treated with gonadotropin releasing hormone (GnRH) on day 5 post-induction. On day 14, only female cattle with at least one CL on their ovaries were classified into two groups: 1CL (original CL; n = 14) and 2CLs groups (original CL + accessory CL; n = 8). In experiment 2, 213 bovine repeat-breeder females were bred using the short-term FTAI protocol. On day 5 post-FTAI, cows were divided into two groups: treatment with (GnRH5-treated group; n = 113) or without (GnRH5-untreated group; n = 100) GnRH. On day 14 post-FTAI, cows were sub-divided into two groups: 1CL (n = 115) and 2CLs (n = 39) groups.Results: In experiment 1, the ovarian luteal diameter, area, and volume per total CLs were greater in 2CLs group compared with 1CL group (P < 0.001). On days 12 and 14 post-induction, female cattle bearing two CLs had greater P concentrations than female cattle bearing only one CL on their ovaries (P < 0.05). In experiment 2, CL number and pregnancy rates were greater in GnRH5-treated group compared with GnRH5-untreated group (P < 0.01). Pregnancy rates were greater in 2CLs cows compared with 1CL cows (P < 0.01). Moreover, female cattle bearing two CLs had a greater likelihood of pregnancy (odds ratio = 20.86) than female cattle bearing only one CL on their ovaries (P = 0.001). Conclusions: In bovine model, our findings confirmed a beneficial effect of an additional CL on ovarian hormone and fertility in infertile female cattle. The results highlighted that increased number of CLs by creating additional CL leads to enhanced peripheral P concentrations and improved pregnancy outcomes in bovine repeat-breeder females undergoing the short-term FTAI protocol.

Endometrial Inflammation at the Time of Insemination and Its Effect on Subsequent Fertility of Dairy Cows

Our objective was to investigate the level of endometrial immune response at artificial insemination (AI) and to relate it to subsequent fertility. From 71 healthy cows, endometrial cytobrush samples were taken at the first AI for cytological and mRNA analyses. Total RNA isolated from the cytobrushes was used for reverse transcription qPCR for selected transcripts. Animals were grouped into pregnant (PREG; n = 32) and non-pregnant (non-PREG; n = 39) cows following their first AI. The mRNA abundance of the neutrophil-related factor CEACAM1 and the chemokine CXCL5 was 1.2- (p = 0.03) and 2.0-fold (p = 0.04) greater in PREG than in non-PREG cows, respectively. Animals were further subdivided according to the number of inseminations until pregnancy (PREG1, n = 32; PREG2-3, n = 19) and in repeat breeder cows (RBC, n = 13). CEACAM1 and CXCL8 mRNA expression was 1.7- (p = 0.01) and 2.3-fold (p = 0.03) greater in PREG1 than in RBC, respectively. Cox regression showed that cows with PMN ≥ 1% had a 1.8-fold increased chance of pregnancy within 150 days postpartum compared with cows with fewer PMNs. We conclude that a certain level of inflammation before the stimulus of AI might be beneficial for subsequent fertility.

Embryo transfer as an option to improve fertility in repeat breeder dairy cows

Repeat breeding is a serious reproductive disorder in dairy cattle. The causes of repeat breeding are multifactorial and there are two main mechanisms: failure of fertilisation or early embryo death, mainly due to poor quality of oocytes and an inadequate uterine environment. Many methods have been used to increase the pregnancy rate for repeat breeder cows, such as intrauterine infusion of antibacterial agents or antibiotics, hormonal treatments for oestrus synchronisation and induction of ovulation, and progesterone supplementation or induction of accessory corpus luteum; however, the results were inconsistent between studies. Embryo transfer (ET) has the capability to minimalise the effects of poor oocyte quality and unfavourable uterine environments on early embryo development during the first seven days after ovulation in repeat breeder cows, and several studies showed that ET significantly improved the pregnancy rate in this group of animals. Thus, ET can be considered an option to increase the conception rate in repeat breeder dairy cows.

Effects of Pre-ovulatory Follicular Fluid of Repeat Breeder Dairy Cows on Bovine Fertility Transcriptomic Markers and Oocytes Maturation and Fertilization Capacity

The current study aimed to determine the effects of the preovulatory follicular fluid (FF) of normal heifer (NH) and repeat breeder cows with subclinical endometritis (SCE) or without (nSCE) on oocyte maturation (Experiment 1) and fertilization rates (Experiment 2). Moreover, the pattern of gene expression of cumulus oocyte-complexes was evaluated in Experiment 1. In Experiment 1, nuclear maturation in the nSCE group was higher, compared to that in the SCE group (P = 0.05). In addition, the oocyte nuclear maturation in the normal heifer was significantly higher, in comparison to that of SCE groups (P &lt; 0.05). Furthermore, the mean percentage of normal oocyte fertilization was higher in the nSCE group, compared to that in the SCE group (P &lt; 0.05). The expressions of growth differentiation factor, GDF9; steroidogenic acute regulatory, StAR and follicle-stimulating hormone receptor, FSHr in the NH group were significantly higher, compared to those in SCE and nSCE groups (P &lt; 0.05). Moreover, the expressions of all genes in the nSCE group were not significant, in comparison to those in the SCE group (P &gt; 0.05). The supplementation of oocyte maturation medium with FF from pre-ovulatory follicles of repeat breeder cows resulted in less oocyte maturation and cumulus cell expansion. In conclusion, the lower fertility in RB cows could be ascribed to the lower oocyte maturation rate and less expression of GDF9, StAR, and FSHr in the cumulus-oocyte complexes.