Dairy grazing: heifer development

Original authors: Tony R. Rickard and Stacey A. Hamilton (University of Missouri). Revised 2022 Scott Poock and Stacey Hamilton.stats082022upload"Dairy heifers are the foundation of any dairy enterprise and directly affect future profitability. Because replacement heifers represent a negative cash flow, this aspect of the dairy operation is often neglected. Unfortunately, this neglect often costs producers large amounts of money. The goals of a heifer program should be to achieve the proper size and weight for the particular breed being raised and to calve by 22 to 24 months of age. Missouri data indicate an average age at first calving of 27 to 28 months. The lost net income per heifer is estimated to be at least $1.50 per day for each day over 24 months of age until freshening."--Page 1.Stacey A. Hamilton (Dairy Specialist, Animal Science Department), Scott E. Poock (State Dairy Extension Veterinarian

Split-time AI : using estrus detection aids to optimize timed artificial insemination (2016)

New July 2016.Includes bibliographical reference

Concurrent and long-term associations between the endometrial microbiota and endometrial transcriptome in postpartum dairy cows

peer-reviewedBackground Fertility in dairy cows depends on ovarian cyclicity and on uterine involution. Ovarian cyclicity and uterine involution are delayed when there is uterine dysbiosis (overgrowth of pathogenic bacteria). Fertility in dairy cows may involve a mechanism through which the uterine microbiota affects ovarian cyclicity as well as the transcriptome of the endometrium within the involuting uterus. The hypothesis was that the transcriptome of the endometrium in postpartum cows would be associated with the cyclicity status of the cow as well as the microbiota during uterine involution. The endometrium of first lactation dairy cows was sampled at 1, 5, and 9 weeks postpartum. All cows were allowed to return to cyclicity without intervention until week 5 and treated with an ovulation synchronization protocol so that sampling at week 9 was on day 13 of the estrous cycle. The endometrial microbiota was measured by 16S rRNA gene sequencing and principal component analysis. The endometrial transcriptome was measured by mRNA sequencing, differential gene expression analysis, and Ingenuity Pathway Analysis. Results The endometrial microbiota changed from week 1 to week 5 but the week 5 and week 9 microbiota were similar. The endometrial transcriptome differed for cows that were either cycling or not cycling at week 5 and cyclicity status depended in part on the endometrial microbiota. Compared with cows cycling at week 5, there were large changes in the transcriptome of cows that progressed from non-cycling at week 5 to cycling at week 9. There was evidence for concurrent and longer-term associations between the endometrial microbiota and transcriptome. The week 1 endometrial microbiota had the greatest effect on the subsequent endometrial transcriptome and this effect was greatest at week 5 and diminished by week 9. Conclusions The cumulative response of the endometrial transcriptome to the microbiota represented the combination of past microbial exposure and current microbial exposure. The endometrial transcriptome in postpartum cows, therefore, depended on the immediate and longer-term effects of the uterine microbiota that acted directly on the uterus. There may also be an indirect mechanism through which the microbiome affects the transcriptome through the restoration of ovarian cyclicity postpartum

Split-time Al : using estrus detection aids to optimize timed artificial insemination (2018)

Timed AI pregnancy rates can be optimized through use of a split-time AI approach following administration of the 14-day CIDR-PG protocol for heifers and the 7-day COSynch + CIDR protocol for mature cows. Using split-time AI, insemination of non-estrous females is delayed until 20 to 24 hours after the scheduled time for fixed-time AI. Estrotect estrus detection aids applied at the time of PG administration allow producers to determine the estrous status of females and inseminate at the optimal time.Includes bibliographical reference

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

Ovarian function and the establishment and maintenance of pregnancy in dairy cows with and without evidence of postpartum uterine disease

Uterine disease early postpartum reduces fertility during the breeding period. One potential mechanism involves the reduced functional capacity of the uterus to support pregnancy. A second potential mechanism involves damage to ovarian follicles associated with systemic inflammation. We categorized lactating Holstein cows into healthy (n = 63) and diseased (n = 39) uterus groups based on the percentage of polymorphonuclear neutrophils in the uterine lumen during the second and third month postpartum and evaluated the functionality of their ovaries and their capacity to establish and maintain pregnancy. Cows were enrolled in a timed artificial insemination protocol (Presynch Ovsynch) so that the first artificial insemination was approximately 75 d postpartum. Ovarian follicles and corpora lutea were counted and measured using transrectal ultrasound, ovulatory responses were assessed, and luteal phase progesterone concentrations were measured. Pregnancy was detected on d 18, 20, 22, 25, 32, and 45 through chemical (d 18 to 25) or ultrasonographic methods (d 32 and 45). The percentage of cows ovulating during the Presynch period; the number, diameter, and ovulatory capacity of follicles during the Ovsynch period; and plasma progesterone concentrations following ovulation were similar for healthy and diseased cows. The initial period of pregnancy establishment (d 18 to 22) appeared to be unaffected by disease because a similar percentage of healthy and diseased cows were pregnant during this period. Embryonic loss occurred in both healthy and diseased cows after d 22. Based on a relatively small number of pregnancies (n = 30 healthy and n = 17 diseased), the cumulative embryonic loss after d 22 was greater in diseased compared with healthy cows. In short, uterine disease as defined in this study did not affect cyclicity, ovarian follicular growth, or plasma progesterone concentrations. Percentages of healthy and diseased cows that were pregnant were similar from d 18 to 22 after artificial insemination. Greater embryonic loss was observed after d 22 in diseased compared with healthy cows, but this observation was based on a small number of pregnancies and should be studied further in larger trials with greater statistical power.UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni

Evaluation of cervical and uterine size, at 4 weeks postpartum, as a predictor of subsequent fertility in Jersey cattle

Uterine and cervical size of Holstein dairy cows is reported among reasons for a decline in dairy cow fertility. Therefore, the objectives of this study were to (a) determine whether size of the cervix and uterus at 4 weeks postpartum impacted subsequent fertility at first service in Jersey cattle, (b) determine whether progesterone level at 4 weeks postpartum impacted cyclicity and (c) the association of the presence of corpus luteum and uterus and cervix size. Body condition scores at calving, presence of postpartum diseases, parity number and milk weights were taken from lactating Jersey dairy cows (N = 147) for 28 days postpartum. During the fourth week postpartum, a blood sample was obtained for progesterone concentration, and transrectal ultrasonography was performed by a high-resolution ultrasound machine to determine cervical and uterine horn diameter, as well as ovarian structures measurements. Correcting for parity number, BCS at calving, presence of diseases and milk yield, cows with a cervix >2.54 ± 0.63 cm and uterine horn >2.25 ± 0.59 cm were less likely to become pregnant at first service (p = .04 and p = .003, respectively). The cows with larger cervix had a trend to be less likely to have a corpus luteum present at the 4th week of lactation (p = .067). Cows with larger uterine horn size were less likely to have a corpus luteum present at the 4th week of lactation (p = .015). It is concluded that a larger cervix and/or uterus during the postpartum was associated negatively with fertility and cyclicity in Jersey cows.UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni