Effects of recombinant bovine interleukin-8 (rbIL-8) treatment on health, metabolism, and lactation performance in Holstein cattle II: Postpartum uterine health, ketosis, and milk production

To evaluate the effect of recombinant bovine interleukin-8 (rbIL-8) on uterine health and milk production, 2 separate studies were conducted. For study 1, postpartum Holstein cows (n = 213) were randomly allocated into 1 of 3 intrauterine treatment groups: control (CTR, 250 mL of saline solution), low dose (L-IL8, 11.25 µg of rbIL-8 diluted in 250 mL of saline solution), and high dose (H-IL8, 1,125 µg of rbIL-8 diluted in 250 mL of saline solution). Intrauterine delivery of treatments was performed within 12 h of parturition. Cows were evaluated for retained fetal membranes, puerperal metritis, and clinical endometritis. Blood samples were collected immediately before treatment and 1, 2, and 3 d in milk for assessment of IL-8, haptoglobin, fatty acids, and β-hydroxybutyrate concentrations. Treatment with rbIL-8 reduced the incidence of puerperal metritis in multiparous cows (CTR = 34.3, L-IL8 = 8.11, and H-IL8 = 6.35%). Both the L-IL8 and H-IL8 groups produced significantly more milk, fat-corrected milk, and energy-corrected milk yields when compared with placebo-treated controls. A second study was performed to confirm the effect of rbIL-8 on milk production. In study 2, 164 primiparous cows were randomly allocated into 1 of 4 treatment groups: control (CTR, 250 mL of saline solution), low dose (L-IL8, 0.14 µg of rbIL-8), medium dose (M-IL8, 14 µg of rbIL-8), and high dose (H-IL8, 1,400 µg of rbIL-8). Treatments were prepared and administered as described for study 1. Cows in the L-IL8, M-IL8, and H-IL8 groups produced significantly more milk, fat-corrected milk, and energy-corrected milk yields when compared with control cows. In conclusion, treatment with rbIL-8 decreased the incidence of puerperal metritis in multiparous cows. The administration of rbIL-8 was repeatedly associated with a dramatic and long-lasting improvement of lactation performance.

Dynamics of the microbiota found in the vaginas of dairy cows during the transition period: Associations with uterine diseases and reproductive outcome

We investigated the microbiota found in the vaginas of Holstein dairy cows during the transition period and described the differences in bacterial composition and total bacterial load (TBL) associated with disease and fertility. Vaginal swabs were collected at -7, 0, 3, and 7 d relative to parturition from 111 dairy cows housed on a commercial dairy farm near Ithaca, New York. Microbiota were characterized by next-generation DNA sequencing of the bacterial 16S rRNA gene, and TBL was determined by real-time quantitative PCR. We applied repeated-measures ANOVA to evaluate the associations of uterine disease and related risk factors with the microbiota and TBL. We estimated phylum-specific bacterial load by multiplying the TBL by the relative abundance of each phylum observed in the metagenomics results. We confirmed the validity of this approach for estimating bacterial load by enumerating the number of bacteria in an artificial sample mixed in vitro and in clinical and healthy vaginal samples. Phyla associated with uterine disease and related risk factors were Proteobacteria, Fusobacteria, and Bacteroidetes. Cows with retained placenta and healthy cows had similar TBL at the day of parturition, but at d 7 postpartum, cows with retained placenta showed a significantly higher TBL, mainly driven by higher estimated loads of Fusobacteria and Bacteroidetes. Cows diagnosed with metritis had a significantly higher estimated load of Proteobacteria at d -7 and at calving and higher estimated loads of Fusobacteria in the postpartum samples. Additionally, the estimated load of Bacteroidetes at d 7 postpartum was higher for cows diagnosed with endometritis at 35 days in milk. Higher estimated loads of Fusobacteria and Bacteroidetes were also evident in cows with postpartum fever, in primiparous cows, in cows with assisted parturition, and in cows that gave birth to twins. Our findings demonstrated that microbiota composition and TBL were associated with known periparturient risk factors of uterine diseases and reproductive failure, including parity, assisted parturition, and retained fetal membranes.

157 EFFECTS OF METABOLIC CONDITIONS OF DAIRY COWS DURING TRANSITION PERIOD AND EARLY LACTATION IN WINTER AND SUMMER ON HEALTH AND FERTILITY

The aim of this study was to investigate and determine which metabolic predictors measured during the transition period, have a better association with health and fertility parameters in dairy cows in winter (W) and summer (S).The experiment was conducted with 235 multiparous Holstein dairy cows. The animals were divided, retrospectively into the experimental groups [High Production (AP), ≥45.9 to 65 kg of milk during peak lactation; Medium production (MP), between 30 and 45.8 kg of milk during peak lactation]. Blood samples and evaluations occurred during the transition period and during the timed fixed artificial insemination (TAI). Data were analysed for the main effects of group, day, and their interaction using the PROC MIXED procedure of SAS software (SAS 9.3, SAS Institute, Inc., Cary, NC, USA). Creatine kinase (CK) plasmatic concentrations increased during peak lactation in all groups, but the difference was not significant. Variations in superoxide dismutase (SOD) concentrations were observed in HP cows in both seasons (HPW and HPS). These cows had higher levels of superoxide dismutase (SOD) when compared of MP cows (MPW and MPS), with significant changes since 7 days before calving and remained higher until 104 days of lactation. The differences were observed in lipid profile, particularly in NEFA concentration. For this variable, there were group (P < 0.001) and day (P < 0.001) effects and also double interactions (day v. season, P < 0.001) and triple interactions (group v. day v. season, P = 0.009). The HPS cows had higher values, as well as a variation pattern of urea concentration (P < 0.05), different from the other groups until 100 days in milk (DEL). No differences were observed in diseases incidences between group or periods (P > 0.05). There was a statistical tendency to all groups in the summer season for earlier calving (P = 0.1), less calf weight (P = 0.07), and retained placenta (P = 0.09) and metritis incidence (P = 0.08). These parameters were strongly correlated with metritis disease incidence and the significant parameters: Earlier calving (P = 0.03), dystocia (P = 0.05), and retained placenta (P = 0.009). The NEFA (0.4 mmol L–1) and BHBA concentrations (0.7 mmol L–1) were highly correlated with the occurrence of uterine diseases. We observed high levels of AST (around 128 U/L) pre calving in ketotic and in cows with displacement of abomasum. According to these results, we concluded that milk production was not a risk factor for fertility in the first three services. Also, metabolic changes in the transition period were determinant in milk yield and health diseases. Research was supported by FAPESP, CNPq, CAPES, Fazenda Colorado, and Ourofino animal health.

23 RELATIONSHIP BETWEEN CONCENTRATION OF SUPEROXIDE DISMUTASE WITH TIME AND TIMED ARTIFICIAL INSEMINATION PREGNANCY RATE IN COWS WITH HIGH MILK PRODUCTION

Disorders related to oxidative metabolism, which occur in the production cycle of high-producing dairy cows (HPC) are more frequent during the transition period and early lactation. Blood concentrations of the enzyme superoxide dismutase (SD) are closely related to the activity of stabilizing conditions of oxidative stress (OS). It is very important to know the main mechanisms involved in regulation of metabolic events, to develop new strategies to increase the productive and reproductive performance of HPC. The objective of this study was to evaluate differences in pregnancy rates and pregnancy losses of HPC with different concentrations of SD with fixed-time AI (FTAI). The experiment was conducted on a commercial farm with 140 HPC (multiparous pregnant Holsteins). The evaluations of concentrations of SD were done from 21 days before birth to the day of the first-service FTAI (75 days in milk), with intervals of 14 days. The animals were retrospectively divided into 2 groups (G1 and G2) in accordance with the average output from all cows in peak lactation (4–8 weeks). Data were analyzed using logistic regression to determine the pregnancy rates between groups. There was a time effect and group effect for the concentrations of SD (P < 0.05) only on the first day of FTAI (3054.4a ± 37.4 and 3662.4 ± 42.1b) for G1 and G2, respectively. But this was not reflected in differences in pregnancy rates between the experimental groups (G1 and G2) and 30 (26.7 v. 31.4) and 60 (20 v. 19.6) days. Although the dismutation activity was high, it seems that the plasma concentration of this enzyme alone does not explain the effects of oxidative stress on fertility in HPC.