Fertility to timed AI (TAI) is profoundly affected by progesterone (P4) levels during hormonal synchronization protocols. Holstein-Friesian dairy cows managed in a seasonal-calving, pasture-based production system were randomly assigned to 2 treatments to manipulate P4 before TAI during growth of the preovulatory follicle. Cows in the first treatment (High P4; n=30) were submitted to a Double-Ovsynch protocol {Pre-Ovsynch [GnRH; 7 d, PGF2α; 3 d, GnRH] followed 7 d later by Breeding-Ovsynch [GnRH (G1); 7 d PGF2α; 24 h, PGF2α; 32 h, GnRH (G2); 16 h, TAI]}. Cows in the second treatment (n=30; Low P4) received the same Double-Ovsynch protocol but with an additional PGF2α treatment 24 h after G1. Overall, synchronization rate did not differ between treatments and was 92% (55/60). Unexpectedly, 37% of Low P4 cows were detected in estrus ~24 h before scheduled TAI and were inseminated ~16 h before scheduled TAI. Overall, P4 did not differ between treatments at G1, whereas High P4 cows had greater P4 concentrations at PGF2α and G2 than Low P4 cows. High P4 cows had the smallest mean follicle diameter at G2, whereas Low P4 cows with no estrus before TAI had intermediate mean follicle diameter at G2, and Low P4 cows with estrus before TAI had the largest mean follicle diameter. Low P4 cows with estrus before TAI had larger corpora lutea 15 d after TAI than Low P4 cows without estrus before TAI or High P4 cows. In accordance with corpus luteum size on d 15, High P4 cows and Low P4 cows without estrus before TAI had lower P4 from 4 to 46 d after TAI than Low P4 cows with estrus before TAI. Relative mRNA levels of the interferon-stimulated genes ISG15, MX1, MX2, and OAS1 were greater for Low P4 than for High P4 cows, whereas relative mRNA levels of RTP4 were greater for High P4 than for Low P4 cows 18 d after TAI. Treatment did not affect plasma pregnancy-associated glycoprotein concentrations after TAI; however, pregnancy-associated glycoprotein concentrations were affected by pregnancy status and parity. Treatment did not affect pregnancy per artificial insemination at 29, 39, or 60 d after TAI, and no pregnancy losses were observed from 39 to 60 d after TAI. We concluded that (1) Low P4 cows were more likely to express estrus than High P4 cows; (2) the subpopulation of Low P4 cows that expressed estrus had larger preovulatory follicles and greater P4 concentrations after TAI; and (3) regardless of estrus before TAI, all Low P4 cows had greater mRNA expression for 5 of 6 interferon-stimulated genes than High P4 cows 18 d after TAI.

The objective of this study was to examine the effect of intravenous infusion of glucose on early embryonic development in lactating dairy cows. Nonpregnant, lactating dairy cows (n = 12) were enrolled in the study (276 ± 17 d in milk). On d 7 after a synchronized estrus, cows were randomly assigned to receive an intravenous infusion of either 750 g/d of exogenous glucose (GLUC; 78 mL/h of 40% glucose wt/vol) or saline (CTRL; 78 mL/h of 0.9% saline solution). The infusion period lasted 7 d and cows were confined to metabolism stalls for the duration of the study. Coincident with the commencement of the infusion on d 7 after estrus, 15 in vitro-produced grade 1 blastocysts were transferred into the uterine horn ipsilateral to the corpus luteum. All animals were slaughtered on d 14 to recover conceptuses, uterine fluid, and endometrial tissue. Glucose infusion increased circulating glucose concentrations (4.70 ± 0.12 vs. 4.15 ± 0.12 mmol/L) but did not affect milk production or dry matter intake. Circulating β-hydroxybutyrate concentrations were decreased (0.51 ± 0.01 vs. 0.70 ± 0.01 mmol/L for GLUC vs. CTRL, respectively) but plasma fatty acids, progesterone, and insulin concentrations were unaffected by treatment. Treatment did not affect either uterine lumen fluid glucose concentration or the mRNA abundance of specific glucose transporters in the endometrium. Mean conceptus length, width, and area on d 14 were reduced in the GLUC treatment compared with the CTRL treatment. A greater proportion of embryos in the CTRL group had elongated to all length cutoff measurements between 11 and 20 mm (measured in 1-mm increments) compared with the GLUC treatment. In conclusion, infusion of glucose into lactating dairy cows from d 7 to d 14 post-estrus during the critical period of conceptus elongation had an adverse impact on early embryonic development.

Background Sedentary behaviour (SB) research has grown exponentially but efficacy for interventions to reduce sedentary behaviour is often contaminated by interventions primarily or co-targeting other behaviours and outcomes. The primary aim of this research therefore, was to systematically review the efficacy of interventions specifically targeting sedentary behaviour reduction, as a sole primary outcome, from randomised control trials in healthy ambulatory adults. This research also sought to identify the successful interventions characteristics, behaviour change techniques (BCT’s) and underlying theories, and their relation to intervention effectiveness. Methods We followed PRISMA reporting guidelines for this systematic review. Six electronic databases were searched and a grey literature review conducted. Only randomised or cluster randomised controlled trials, from 2000 to 2020, in adult populations with a sole primary outcome of change in sedentary behaviour were included. Data codebooks were developed, data were extracted, and a narrative synthesis and meta-analysis was conducted using mixed methods random effects models. Results Of 5589 studies identified, 7 studies met the inclusion criteria. Six studies reported activPAL3 measures of mean daily sitting time, and four reported mean daily standing time, stepping time and number of sedentary breaks. Pooled analysis of weighted mean differences revealed a reduction in mean daily sitting time of -32.4mins CI (-50.3, -14.4), an increase in mean daily standing time of 31.75mins CI (13.7, 49.8), and mean daily stepping time of 9.5mins CI (2.8, 16.3), and an increase in rate of sedentary breaks per day of 3.6 (CI 1.6, 5.6). BCTs used exclusively in two of the three most effective interventions are ‘feedback on behaviour’ and ‘goal setting behaviour’ whilst all three most effective interventions included ‘instruction on how to perform the behaviour’ and ‘adding objects to the environment’, BCTs which were also used in less effective interventions. Conclusions Although limited by small sample sizes and short follow up periods, this review suggests that interventions specifically designed to change sedentary behaviour, reduce overall daily sitting time by half an hour, with an equivalent increase in standing time, in the short to medium term. Effective characteristics and behaviour change strategies are identified for future development of high quality interventions targeting change in sedentary behaviour. Prospero registration PROSPERO 2020 CRD42020172457 Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020172457.

Heterogeneity of descriptors and outcomes measured and reported in sedentary behaviour (SB) research hinder the meta-analysis of data and accumulation of evidence. The objective of the Core Research Outcomes for Sedentary Behaviour Interventions (CROSBI) consensus study was to identify and validate, a core outcome set (COS) to report (what, how, when to measure) in interventional sedentary behaviour studies. Outcomes, extracted from a systematic literature review, were categorized into domains and data items (COS v0.0). International experts (n = 5) provided feedback and identified additional items, which were incorporated into COS v0.1. A two round online Delphi survey was conducted to seek consensus from a wider stakeholder group and outcomes that achieved consensus in the second round COS (v0.2), were ratified by the expert panel. The final COS (v1.0) contains 53 data items across 12 domains, relating to demographics, device details, wear-time criteria, wear-time measures, posture-related measures, sedentary breaks, sedentary bouts and physical activity. Notably, results indicate that sedentary behaviour outcomes should be measured by devices that include an inclinometry or postural function. The proposed standardised COS is available openly to enhance the accumulation of pooled evidence in future sedentary behaviour intervention research and practice.