Dynamic principles of the microbiome and the bovine vagina: a review.

The role of microbes inhabiting various body sites in supporting host physiology and health is substantial, and recent advancements in DNA sequencing technology have facilitated a more in-depth understanding of these microbial contributions. The influence of microbiota within a given organ can be broadly categorized as having two main functions: (1) promoting organ homeostasis and (2) creating conditions that inhibit the growth of pathogenic microorganisms, thereby protecting the host from diseases. In livestock production, numerous phenotypes critical to industry outcomes are affected by the microbiome, which has sparked considerable academic interest in recent years.

Interleukin-6 supplementation improves bovine conceptus elongation and transcriptomic indicators of developmental competence†.

A high incidence of pregnancy failures occurs in cattle during the second week of pregnancy as blastocysts transition into an elongated conceptus. This work explored whether interleukin-6 supplementation during in vitro embryo production would improve subsequent conceptus development. Bovine embryos were treated with 0 or 100 ng/mL recombinant bovine interleukin-6 beginning on day 5 post-fertilization.

Evaluation of the stress-reducing effect of trace mineral injection in beef calves.

Background: Little is known about the effects of trace mineral supplementation on the stress response in beef calves.

Objectives: To investigate the effect of injectable trace mineral supplementation (ITM) on the stress response in beef calves exposed to different types of stress.

Animals: Thirty weaned Angus and Angus crossbred calves.

Reproductive and lactational responses of multiparous dairy cattle to short-term postpartum chromium supplementation during the summer months.

The objective of this work was to evaluate the potential benefits of short-duration, high-dose chromium (Cr) supplementation in early postpartum dairy cows during the summer months. Multiparous, early-lactation cows (20.95 ± 0.

Effects of temperament on reproductive performance of heifers enrolled in the 7-day CO-Synch + controlled internal drug release protocol.

Cattle temperament significantly impacts production traits such as reproduction. The objective of this study was to assess the effects of temperament on pregnancy rates to fixed-timed artificial insemination (TAI) in beef heifers. A total of 297 Angus influenced heifers from 3 different locations were evaluated for temperament based on chute score and exit velocity on the first day of the estrus synchronization protocol (d-9) and classified by temperament type based on temperament score (calm ≤ 3 < excitable).

Delayed processing of blood samples impairs the accuracy of mRNA-based biomarkers.

The transcriptome of peripheral white blood cells (PWBCs) are indicators of an organism's physiological state, thus making them a prime biological sample for mRNA-based biomarker discovery. Here, we designed an experiment to evaluate the impact of delayed processing of whole blood samples on gene transcript abundance in PWBCs. We hypothesized that storing blood samples for 24 h at 4 °C would cause RNA degradation resulting in altered transcriptome profiles.

Effects of Nerve Growth Factor-β From Bull Seminal Plasma on Steroidogenesis and Angiogenic Markers of the Bovine Pre-ovulatory Follicle Wall Cell Culture.

Nerve growth factor-β (NGF) is critical for ovulation in the mammalian ovary and is luteotrophic when administered systemically to camelids and cattle. This study aimed to assess the direct effects of purified bovine NGF on steroidogenesis and angiogenic markers in the bovine pre-ovulatory follicle. Holstein heifers ( = 2) were synchronized with a standard protocol, and heifers with a preovulatory follicle (≥ 12 mm) had the ovary containing the dominant follicle removed via colpotomy.

A retrospective analysis of bull:cow ratio effects on pregnancy rates of beef cows previously enrolled in fixed-time artificial insemination protocols.

This retrospective study aimed to determine if the number of cows exposed per bull affects pregnancy rates of cows returning to estrus after fixed-time artificial insemination (FTAI). Data were compiled over the course of 13 breeding seasons (six fall and seven spring seasons) between 2010 and 2017 from the Virginia Department of Corrections herd. Available records contained data from 17 farms and 324 groups of cows (average 47 cows/group).

Habituation Protocols Improve Behavioral and Physiological Responses of Beef Cattle Exposed to Students in an Animal Handling Class.

Our objective was to determine the impact of different habituation protocols on beef cattle behavior, physiology, and temperament in response to human handling. Beef heifers were exposed to three habituation strategies: (1) tactile stimulation (brushing) in the working chute for seven consecutive days (STI; = 18); (2) passage through the working chute for seven consecutive days (CHU; = 19) and; (3) no habituation (CON; = 19). Individual heifer respiratory rate (RR; n/min), internal vaginal temperature (VAGT; °C), and blood cortisol were measured.

Comparison of reproductive performance of AI- and natural service-sired beef females under commercial management.

The objective of this study was to assess differences in reproductive performance of natural service and artificial insemination () sired beef females based on pregnancy outcomes, age at first calving, and calving interval. Data were sourced from 8,938 cows sired by AI bulls and 3,320 cows sired by natural service bulls between 2010 and 2017. All cows were in a commercial Angus herd with 17 management units located throughout Virginia and represented spring and fall calving seasons.

Interleukin-6 supplementation improves post-transfer embryonic and fetal development of in vitro-produced bovine embryos.

The use of in vitro produced embryos in dairy and beef cattle has increased in recent years, but compromised post-transfer pregnancy success prevents producers from capturing all the benefits this technology can provide. This study explored whether supplementing interleukin-6 (IL6) during in vitro embryo development influences post-transfer development of the embryo-proper, fetus and placenta during early gestation in cattle. Slaughterhouse-derived cumulus oocyte complexes underwent IVM (day -1) and IVF (day 0).

Cattle stress and pregnancy responses when imposing different restraint methods for conducting fixed time artificial insemination.

Physiological stress responses have been associated with lesser pregnancy rates in beef cattle. Alternative cattle restraint methods have been developed to reduce this negative effect. The objective was to determine if there was a difference in pregnancy rate as a result of fixed-time artificial insemination (FTAI) in Bos taurus females when using a breeding box compared with a squeeze chute for restraining cows when conducting FTAI.

Administration of nerve growth factor-β to heifers with a pre-ovulatory follicle enhanced luteal formation and function and promoted LH release.

The objective of this study was to determine the effects of bovine nerve growth factor-β (NGF) on pre-ovulatory follicle vascular area, LH release, ovulation, and luteal function when administered systemically to heifers. Post-pubertal Holstein heifers (n = 12) received an intravaginal progesterone-releasing device (CIDR) and GnRH agonist (100 μg IM). The CIDR was removed 5 d later, and heifers were given dinoprost (25 mg IM) at CIDR removal and 24 h later, followed by a second dose of GnRH agonist 48 h later.

Assessment of peripheral markers and ultrasonographic parameters in pregnant mares receiving intramuscular or intrauterine cloprostenol.

The present study aimed to compare two methods of prostaglandin-induced abortion in mares by determining blood markers (progesterone, estradiol-17β, alpha-fetoprotein, 13,14-dihydro-15-keto-prostaglandin-F2α (PGFM)), B-mode ultrasonographic parameters, and time until loss of fetal heartbeat. It was hypothesized that intrauterine infusion of cloprostenol results in earlier fetal compromise than intramuscular administration. Ovarian structures (number and sizes of follicles and corpora lutea area), fetal heartbeat, and fetal mobility of thirteen singleton pregnancies were assessed daily by transrectal ultrasonography until induction of pregnancy termination (60 ± 2 days of gestation).

Supplementing Ca salts of soybean oil after artificial insemination increases pregnancy success in Bos taurus beef cows.

Two experiments investigated the effects of supplementing Ca salts of soybean oil (CSSO) during early gestation on reproductive function and pregnancy rates to AI in Bos taurus beef cows. In Exp. 1, 771 suckled, lactating, multiparous Angus cows were divided into 22 groups of approximately 35 cows per group and timed inseminated on day 0.

Nerve Growth Factor-Beta, purified from bull seminal plasma, enhances corpus luteum formation and conceptus development in Bos taurus cows.

The objective of the current study was to determine if Nerve Growth Factor-Beta (NGF), purified from bovine seminal plasma, would improve corpus luteum function and enhance conceptus development when administered to cows at artificial insemination. Angus cows (n = 60) were synchronized using a GnRH-prostaglandin and intravaginal progesterone protocol (7-day CO-Synch/CIDR) and randomly allocated to 1 of 2 treatment groups: (1) CONT- 12 mL PBS; or (2) NGF- 296 μg purified NGF in 12 mL PBS administered intramuscularly at insemination (day 0). Blood collections were performed to measure plasma concentrations of progesterone (days 0, 3, 7, 10, 14, 19) and pregnancy-specific protein B (day 24) using immunoassays.