Application of behavior data to predictive exploratory models of metritis self-cure and treatment failure in dairy cows.

The objective was to evaluate the performance of exploratory models containing routinely available on-farm data, behavior data, and the combination of both to predict metritis self-cure (SC) and treatment failure (TF). Holstein cows (n = 1,061) were fitted with a collar-mounted automated-health monitoring device (AHMD) from -21 ± 3 to 60 ± 3 d relative to calving to monitor rumination time and activity. Cows were examined for diagnosis of metritis at 4 ± 1, 7 ± 1, and 9 ± 1 d in milk (DIM). Cows diagnosed with metritis (n = 132), characterized by watery, fetid, reddish/brownish vaginal discharge (VD), were randomly allocated to 1 of 2 treatments: control (CON; n = 62), no treatment at the time of metritis diagnosis (d 0); or ceftiofur (CEF; n = 70), subcutaneous injection of 6.6 mg/kg of ceftiofur crystalline-free acid on d 0 and 3 relative to diagnosis. Cure was determined 12 d after diagnosis and was considered when VD became mucoid and not fetid. Cows in CON were used to determine SC, and cows in CEF were used to determine TF. Univariable analyses were performed using farm-collected data (parity, calving season, calving-related disorders, body condition score, rectal temperature, and DIM at metritis diagnosis) and behavior data (i.e., daily averages of rumination time, activity generated by AHMD, and derived variables) to assess their association with metritis SC or TF. Variables with P-values ≤0.20 were included in the multivariable logistic regression exploratory models. To predict SC, the area under the curve (AUC) for the exploratory model containing only data routinely available on-farm was 0.75. The final exploratory model to predict SC combining routinely available on-farm data and behavior data increased the AUC to 0.87, with sensitivity (Se) of 89% and specificity (Sp) of 77%. To predict TF, the AUC for the exploratory model containing only data routinely available on-farm was 0.90. The final exploratory model combining routinely available on-farm data and behavior data increased the AUC to 0.93, with Se of 93% and Sp of 87%. Cross-validation analysis revealed that generalizability of the exploratory models was poor, which indicates that the findings are applicable to the conditions of the present exploratory study. In summary, the addition of behavior data contributed to increasing the prediction of SC and TF. Developing and validating accurate prediction models for SC could lead to a reduction in antimicrobial use, whereas accurate prediction of cows that would have TF may allow for better management decisions.

Induced endometrial inflammation compromises conceptus development in dairy cattle†.

Endometrial inflammation is associated with reduced pregnancy per artificial insemination (AI) and increased pregnancy loss in cows. It was hypothesized that induced endometritis alters histotroph composition and induces inflammatory signatures on conceptus that compromise development. In Experiment 1, lactating cows were assigned to control (CON; n = 23) or to an intrauterine infusion of Escherichia coli and Trueperella pyogenes (ENDO; n = 34) to induce endometritis. Cows received AI 26 days after treatment, and the uterine fluid and conceptuses were collected on day 16 after AI. In Experiment 2, Holstein heifers were assigned to CON (n = 14) or ENDO (n = 14). An embryo was transferred on day 7 of the estrous cycle, and uterine fluid and conceptuses were recovered on day 16. Composition of histotroph and trophoblast and embryonic disc gene expression were assessed. Bacterial-induced endometritis in lactating cows altered histotroph composition and pathways linked to phospholipid synthesis, cellular energy production, and the Warburg effect. Also, ENDO reduced conceptus length in cows and altered expression of genes involved in pathogen recognition, nutrient uptake, cell growth, choline metabolism, and conceptus signaling needed for maternal recognition of pregnancy. The impact of ENDO was lesser on conceptuses from heifers receiving embryo transfer; however, the affected genes and associated pathways involved restricted growth and increased immune response similar to the observed responses to ENDO in conceptuses from lactating cows. Bacterial-induced endometrial inflammation altered histotroph composition, reduced conceptus growth, and caused embryonic cells to activate survival rather than anabolic pathways that could compromise development.

Reproduction in the era of genomics and automation.

Much progress has been made in the reproductive efficiency of lactating dairy cows across the USA in the past 20years. The standardisation of evaluation of reproductive efficiency, particularly with greater focus on metrics with lesser momentum and less lag-time such as 21-day pregnancy rates (21-day PR), and the recognition that subpar reproductive efficiency negatively impacted profitability were major drivers for the changes that resulted in such progress. Once it became evident that the genetic selection of cattle for milk yield regardless of fertility traits was associated with reduced fertility, geneticists raced to identify fertility traits that could be incorporated in genetic selection programs with the hopes of improving fertility of lactating cows. Concurrently, reproductive physiologists developed ovulation synchronisation protocols such that after sequential treatment with exogenous hormones, cows could be inseminated at fixed time and without detection of oestrus and still achieve acceptable pregnancy per service. These genetic and reproductive management innovations, concurrently with improved husbandry and nutrition of periparturient cows, quickly started to move reproductive efficiency of lactating dairy cows to an upward trend that continues today. Automation has been adopted in Israel and European countries for decades, but only recently have these automated systems been more widely adopted in the USA. The selection of dairy cattle based on genetic indexes that result in positive fertility traits (e.g. daughter pregnancy rate) is positively associated with follicular growth, resumption of ovarian cycles postpartum, body condition score and insulin-like growth factor 1 concentration postpartum, and intensity of oestrus. Collectively, these positive physiological characteristics result in improved reproductive performance. Through the use of automated monitoring devices (AMD), it is possible to identify cows that resume cyclicity sooner after calving and have more intense oestrus postpartum, which are generally cows that have a more successful periparturient period. Recent experiments have demonstrated that it may be possible to adopt targeted reproductive management, utilising ovulation synchronisation protocols for cows that do not have intense oestrus postpartum and relying more heavily on insemination at AMD-detected oestrus for cows that display an intense oestrus postpartum. This strategy is likely to result in tailored hormonal therapy that will be better accepted by the public, will increase the reliance on oestrus for insemination, will improve comfort and reduce labour by reducing the number of injections cows receive in a lactation, and will allow for faster decisions about cows that should not be eligible for insemination.

Targeted reproductive management for lactating Holstein cows: Reducing the reliance on exogenous reproductive hormones.

Adoption of automated monitoring devices (AMD) affords the opportunity to tailor reproductive management according to the cow's needs. We hypothesized that a targeted reproductive management (TRM) would reduce the use of reproductive hormones while increasing the percentage of cows pregnant 305 d in milk (DIM). Holstein cows from 2 herds (n = 1,930) were fitted with an AMD at 251.0 ± 0.4 d of gestation. Early-postpartum estrus characteristics (EPEC; intense estrus = heat index ≥70; 0 = minimum, 100 = maximum) of multiparous cows were evaluated at 40 (herd 1) or 41 (herd 2) DIM and EPEC of primiparous cows were evaluated at 54 (herd 1) or 55 (herd 2) DIM. Control cows received the first artificial insemination at fixed time (TAI; primiparous, herd 1 = 82 and herd 2 = 83 DIM; multiparous, herd 1 = 68 and herd 2 = 69 DIM) following the Double-Ovsynch (DOV) protocol. Cows enrolled in the TRM treatment were managed as follows: (1) cows with at least one intense estrus were inseminated upon AMD detected estrus for 42 d and, if not inseminated, were enrolled in the DOV protocol; and (2) cows without an intense estrus were enrolled in the DOV protocol at the same time as cows in the control treatment. Control cows were re-inseminated based on visual or patch aided detection of estrus, whereas TRM cows were re-inseminated as described for control cows with the aid of the AMD. Cows received a GnRH injection 27 ± 3 d after insemination and, if diagnosed as nonpregnant, completed the 5-d Cosynch protocol and received TAI 35 ± 3 d after insemination. Among cows in the TRM treatment, 55.8 and 42.9% of primiparous and multiparous cows, respectively, received the first insemination in spontaneous estrus. The interaction between treatment and parity affected pregnancy 67 d after the first AI (primiparous: control = 37.6%, TRM = 27.4%; multiparous: control = 41.0%, TRM = 44.7%). The TRM treatment increased re-insemination in estrus (control = 48.3%, TRM = 70.5%). Pregnancy 67 d after re-inseminations tended to be affected by the interaction between treatment and EPEC (no intense estrus: control = 25.3%, TRM = 32.0%; intense estrus: control = 32.9%, TRM = 32.2%). The interaction between treatment and EPEC affected pregnancy by 305 DIM (no intense estrus: control = 80.8%, TRM = 88.2%; intense estrus: control = 87.1%, TRM = 86.1%). Treatment did not affect the number of reproductive hormone treatments among cows that had not had an intense estrus (control = 10.5 ± 0.3, TRM = 9.1 ± 0.2 treatments/cow), but cows in the TRM treatment that had an intense estrus received fewer reproductive hormone treatments than cows in the control treatment (2.0 ± 0.1 vs. 9.6 ± 0.2 treatments/cow). Selecting multiparous cows for first AI in estrus based on EPEC reduced the use of reproductive hormones without impairing the likelihood of pregnancy to first AI. The use of AMD for re-insemination expedited the establishment of pregnancy among cows that did not display an intense estrus early postpartum.

Heat abatement during the pre-weaning period: effects on lying behavior and disbudding-related responses of male Holstein calves.

Strategies to abate heat stress are seldom adopted for pre-weaned dairy calves and little is known about their effects on behavior and pain sensitivity of youngstock. Our objectives were to determine the effects of heat stress abatement on lying behavior and disbudding-related pain sensitivity, wound healing, and change in intake. Male Holstein calves (n = 60; 0 to 68 d of age) were assigned randomly at birth (d 0) to 1 of 3 treatments: hutch outdoors with 50% of its area covered with plywood (control = 20), hutch in a barn with no cooling (SH = 21), and hutch in a barn with ceiling fans (SHF = 19). Calves were fitted with lying-behavior loggers on the hind leg from d 1 to 68. On d 32 ± 8 (±SD), we disbudded calves using hot iron, 30 min after cornual nerves were blocked with lidocaine. Immediately before (0 h), and at 1, 2, and 3 h after disbudding, we evaluated calves for mechanical nociceptive threshold (MNT) and head (ear flick, head shake, head rubbing) and somatic (tail flicking, foot stamping, restlessness) behaviors. On d 1, 3, 7, and 14 after disbudding, we evaluated the MNT and, on d 7 and 14, we evaluated wound healing (1 = crust, 5 = exudate). We calculated the relative change in milk solids and starter intake from d 0 to 6 relative to disbudding compared with the average of the 72 h preceding the procedure. The lying time was 0.6 h/d greater for the SHF treatment compared with the SH treatment. The control treatment resulted in 3.2 and 4.1 more lying bouts per day than the SH and SHF treatments, respectively; consequently, the control treatment resulted in lying-bout duration 7.7 and 10.9 min/event shorter than the SH and SHF treatments, respectively. We did not detect an effect of treatment on the number of disbudding-related head and somatic behaviors and MNT. The odds of calves having abnormal wound was 3.5 and 3.2 times greater for the control treatment compared with the SH and SHF treatments, respectively. We did not detect an effect of treatment on the relative change in intake of milk solids and starter. Heat abatement improves the welfare of pre-weaned dairy calves and may hasten healing.

Heat abatement during the pre-weaning period: effects on growth, feed efficiency, metabolites, and insulin of male Holstein calves.

Heat stress abatement strategies for pre-weaned dairy calves are seldom evaluated. An experiment was conducted to evaluate the effects of housing calves under a barn and provision of fans to calves housed under a barn on calfhood performance. The experiment was conducted in a dairy in southern Georgia, USA. Male Holstein calves (n = 60; 0 to 68 day of age) were assigned randomly at birth (day 0) to 1 of 3 treatments: hutch outdoors with 50% of its area covered with plywood (control = 20), hutch in a barn with no cooling (SH = 21), and hutch in a barn with ceiling fans (SHF = 19). Body weight (BW) was measured at birth, and total serum protein and wither-height were measured 24 to 48 h after birth. A sub-set of hutches was evaluated for air speed and temperature, and rectal temperature (RT) and respiratory frequency (RF) of calves housed in these hutches were measured at 0900 and 1500 h. Intakes of liquid feed (days 14 to 63) and starter (days 14 to 68) were recorded daily, BW and wither-height were measured weekly, and feed efficiency was calculated weekly. Blood was sampled on days 1, 14, 28, 42, 49, 52, 56, 58, 63, and 65 for the measurement of fatty acids, ß-hydroxybutyrate, glucose, and insulin. The SHF treatment resulted in air velocity 0.56 to 0.83 m/s greater (P < 0.01) than the control and SH treatments, respectively, whereas the control treatment resulted in air temperature 1.2 to 3.2 °C greater (P < 0.01) than the SH and SHF treatments, respectively. The RT of calves in the control treatment was 0.1 to 1.1 °C greater (P ≤ 0.03) than the SH and SHF treatments, respectively, and the control treatment resulted in RF 39.4 to 60.2 mov/min greater (P < 0.01) than the SH and SHF treatments, respectively. Treatment did not (P ≥ 0.27) affect feed efficiency and concentrations of metabolites and insulin, but calves in the control treatment were 2.6 cm shorter (P = 0.03) than calves in the SHF treatments at weaning. Provision of fans to calves housed under a barn reduced RT, RF, but only had a minute impact on wither-height.

Associations between days on close-up diets and immune responses prepartum, metabolites peripartum, and risk of postpartum diseases in Jersey cows.

Nutritional strategies during the final weeks prepartum, the close-up period, aim to reduce immune suppression and metabolic imbalances. This paper reports results of 2 observational studies. Data from 2 previous experiments (study 1) were used to investigate the associations between days fed close-up diets (DINCUD) and uterine diseases (n = 1,230). In study 2, retrospective data from animals not used in study 1 (n = 11,962) were used to investigate the associations between DINCUD and removal from the herd and long-term reproductive and productive responses. Nulliparous (lactation = 0) and parous (lactation ≥1) cows were moved to close-up pens 28 d before expected calving date, but only parous cows were fed rations with negative dietary cation-anion difference. In study 1, study personnel diagnosed retained fetal membranes, metritis, and acute metritis postpartum. Length of the close-up period was tested for its linear and quadratic effects. The ß-coefficients from the multivariable analyses were used to calculate the predicted outcome for each cow. In addition, the mean (±SEM) for cows with <10, 28 ± 3, and 42 ± 3 DINCUD are reported. Metritis was associated with the interaction between DINCUD and parity-diet (nulliparous: <10 d = 31.8 ± 9.2, 28 ± 3 d = 21.8 ± 0.7, 42 ± 3 d = 29.8 ± 2.1%; parous: <10 d = 81.7 ± 2.9, 28 ± 3 d = 11.1 ± 0.3, 42 ± 3 d = 14.8 ± 1.3%). The interaction between DINCUD and parity-diet was associated with total energy-corrected milk yield (nulliparous: ≤10 d = 7.91 ± 0.03, 28 ± 3 d = 8.17 ± 0.01, 42 ± 3 d = 8.15 ± 0.01 kg × 103; parous: ≤10 d = 7.99 ± 0.05, 28 ± 3 d = 9.79 ± 0.01, 42 ± 3 d = 9.52 ± 0.03 kg × 103) and percentage of cows pregnant by 305 days in milk (DIM; nulliparous: ≤10 d = 80.4 ± 0.4, 28 ± 3 d = 83.3 ± 0.1, 42 ± 3 d = 82.8 ± 0.2%; parous: ≤10 d = 59.5 ± 0.7, 28 ± 3 d = 78.3 ± 0.1, 42 ± 3 d = 73.1 ± 0.5%). Furthermore, the interaction between DINCUD and parity-diet was associated with removal from the herd by 305 DIM (nulliparous: ≤10 d = 27.0 ± 0.5, 28 ± 3 d = 20.7 ± 0.1, 42 ± 3 d = 21.8 ± 0.1%; parous: ≤10 d = 45.1 ± 0.7, 28 ± 3 d = 31.1 ± 0.1, 42 ± 3 d = 28.1 ± 0.3%). Jersey cows that are managed to achieve 28 DINCUD may have reduced odds of uterine diseases and improved reproductive and productive performances.

Effects of adding an automated monitoring device to the health screening of postpartum Holstein cows on survival and productive and reproductive performances.

Automated monitoring devices (AMD) have become more affordable, and consequently more popular among dairy producers. We hypothesized that the addition of AMD-generated health alerts to a health-screening program improves survival, milk production, and reproductive success. In addition, we hypothesized that cows diagnosed with clinical disease that have AMD alerts are at greater risk of culling, lower milk production, and decreased risk of pregnancy than cows without AMD alerts. Holstein cows (nulliparous = 282, parous = 328) were enrolled at -60 ± 3 d (d 0 = calving), when they were fitted with an AMD and assigned randomly to 1 of 2 health-screening strategies: (1) control: AMD alerts not provided to farm personnel; and (2) automated device: AMD alerts provided to farm personnel. Twice daily, study personnel determined which cows had AMD alerts (health index ≤79, rumination <200 min/d, or difference between current rumination and the average of the 3 preceding days <0) and provided the information to farm personnel. Farm personnel examined cows at 3, 5, and 9 d in milk (DIM) and when daily milk yield decreased ≥25% on consecutive days. We detected no differences between health-screening strategies regarding morbidity (control = 49.7 ± 3.3%, automated device = 52.8 ± 3.2%), but the interaction between health-screening strategy and parity tended to be associated with the number of clinical diseases per cow (primiparous: control = 0.46 ± 0.06, automated device = 0.65 ± 0.07 cases/cow; multiparous: 0.88 ± 0.08, automated device = 0.86 ± 0.08 cases/cow). Cows enrolled in the automated device strategy were more likely to be treated with supportive therapy (64.4 ± 3.1 vs. 55.0 ± 3.2%), whereas primiparous cows in the automated device strategy were more likely to be treated with anti-inflammatory drugs than those in the control strategy (41.6 ± 4.7 vs. 23.8 ± 4.0%). Health-screening strategy did not affect survival or total milk yield up to 22 wk postpartum, but cows in the automated device strategy had reduced risk of pregnancy after the first 2 services (54.5 ± 3.0 vs. 46.2 ± 3.2%). Cows diagnosed with a clinical disease without AMD alerts had reduced risk of removal from the herd by 150 DIM (5.7 ± 2.0 vs. 19.0 ± 3.3%), greater risk of pregnancy after the first 2 services (49.6 ± 4.5 vs. 33.6 ± 3.9%), and greater milk by 22 wk postpartum (6.7 ± 0.2 vs. 5.3 ± 0.2 × 103 kg) than cows diagnosed with a clinical disease that had an AMD alert. Adding AMD-generated health alerts to the health screening of postpartum cows in a herd with an existing screening program did not improve survival, milk yield, or reproductive success. In addition, AMD alerts in cows diagnosed with a clinical disease may be indicative of the future success of such cows.

Associations between genomic merit for daughter pregnancy rate of Holstein cows and metabolites postpartum and estrus characteristics.

Genetic selection of Holstein cattle in the past 2 decades has seen an increased attention to fertility traits. Our hypotheses were that genomic merit for daughter pregnancy rate (GDPR) is positively associated with metabolic responses, hazard of estrus, and estrus characteristics. Pregnant heifers (n = 821) from one herd that were genotyped within 2 mo of birth (Clarifide, Zoetis, Parsippany, NJ) were fitted with automated monitoring devices (SCR Inc., Netanya, Israel) -21 ± 14 d relative to calving. Estrus characteristics recorded from calving to 62 d postpartum were evaluated. Blood samples were collected weekly from a subsample (n = 499) of cows, from 7 to 28 d postpartum, for determination of insulin-like growth factor-1, glucose, and nonesterified fatty acids. Cows received artificial insemination or embryo transfer following detected estrus and those not detected in estrus were submitted to an ovulation synchronization protocol starting at 75 d in milk. Linear and quadratic associations between GDPR and outcomes were analyzed, but when appropriate, results are presented according to GDPR quartile (Q1 = -1.8 to 0.8; Q2 = 0.9 to 1.7; Q3 = 1.8 to 2.5; Q4 = 2.6 to 5.9) based on the parameter estimates of the multivariable models. Genomic merit for daughter pregnancy rate was positively associated with insulin-like growth factor-1 (Q1 = 24.3 ± 0.2; Q2 = 26.8 ± 0.2; Q3 = 28.2 ± 0.2; Q4 = 30.6 ± 0.3 ng/mL) and glucose (Q1 = 67.0 ± 0.1; Q2 = 69.1 ± 0.2; Q3 = 69.6 ± 0.2; Q4 = 70.8 ± 0.2 mg/dL) concentrations, but GDPR was negatively associated with nonesterified fatty acid concentration (Q1 = 281.2 ± 4.9; Q2 = 262.0 ± 5.9; Q3 = 239.3 ± 5.0; Q4 = 221.6 ± 4.7 µmol/L). A positive association was observed between GDPR and hazard of estrus [adjusted hazard ratio and 95% confidence interval = 1.16 (1.06, 1.28)] and number of estrus events (Q1 = 0.50 ± 0.03; Q2 = 0.62 ± 0.04; Q3 = 0.74 ± 0.05; Q4 = 0.86 ± 0.06) within 62 d postpartum, duration of estrus (Q1 = 14.10 ± 0.04; Q2 = 14.48 ± 0.04; Q3 = 14.67 ± 0.04; Q4 = 14.98 ± 0.04 h), probability of activity peak (0 = no estrus, 100 = maximum activity) ≥86 (Q1 = 0.80 ± 0.03; Q2 = 0.83 ± 0.02; Q3 = 0.83 ± 0.03; Q4 = 0.85 ± 0.2), and probability of heat index ≥86 (Q1 = 0.77 ± 0.04; Q2 = 0.81 ± 0.05; Q3 = 0.83 ± 0.03; Q4 = 0.86 ± 0.03). Conversely, GDPR was negatively associated with rumination nadir at estrus (Q1 = -35.5 ± 0.1; Q2 = -37.0 ± 0.1; Q3 = -38.0 ± 0.1; Q4 = -39.6 ± 0.1 min). We detected a positive association between GDPR and hazard of pregnancy (adjusted hazard ratio = 1.11, 95% confidence interval = 1.03, 1.19). Selection for GDPR may improve the hormonal and metabolic status of cows postpartum, leading to earlier resumption of cyclicity, and may improve detection of estrus in commercial herds because it was positively associated with estrus characteristics.

Optimization of timing of insemination of dairy heifers inseminated with sex-sorted semen.

We hypothesized that delaying by approximately 12 h the artificial insemination (AI) of heifers with sex-sorted semen increases pregnancy per AI (P/AI). Holstein heifers (n = 1,207) were fitted with a collar containing an automated estrus-detection device (HR-LDn tags, SCR Engineers Ltd., Netanya, Israel) at 10.7 ± 0.02 mo of age. Once they reached 330 kg, heifers were enrolled in an ovulation synchronization protocol (5-d Cosynch + controlled internal drug release; Zoetis, Parsippany-Troy Hills, NJ). Study personnel recorded the heifers that were in estrus according to the DataFlow II software (SCR Engineers Ltd., Netanya, Israel) twice daily at 0500 and 1500 h from the day of the first PGF2α (Estrumate; Merck Animal Health, Madison, NJ) injection to 72 h later. Heifers enrolled in the conventional (CONV) and early sex-sorted (SSEarly) semen treatments detected in estrus at 0500 and 1500 h were AI at 0600 and 1600 h of the same day, respectively. Heifers enrolled in the late sex-sorted (SSLate) semen treatment detected in estrus at 0500 and 1500 h were AI at 1600 h of the same day and 0600 h of the following day, respectively. All heifers not detected in estrus by 72 h after the first PGF2α injection received a GnRH (Fertagyl; Merck Animal Health, Madison, NJ) injection at 0500 h. Heifers in the CONV and SSEarly treatments were AI at fixed time at 0600 h, whereas heifers in the SSLate treatment were AI at fixed time at 1600 h. Among heifers detected in estrus, the ranges of the interval from the onset of estrus to AI were 3.6 to 28.5 h, 0.0 to 25.5 h, and 9.4 to 36.8 h for the CONV, SSEarly, and SSLate treatments, respectively. Among heifers AI at fixed time, the ranges of the interval from the GnRH injection to AI were 0 h for heifers in the CONV and SSEarly treatments and 8.5 to 11.7 h for heifers in the SSLate treatment. The P/AI at 62 ± 1 d after the first AI was greater for CONV (63.1 ± 2.6%) compared with SSEarly (43.3 ± 2.6%) and SSLate (44.8 ± 2.7%). A greater percentage of heifers enrolled in the SSEarly (65.8 ± 2.5%) and SSLate (70.0 ± 2.5%) treatments produced a live female calf compared with the CONV treatment (40.5 ± 2.7%). When the values of 1-d-old female and male calves were USD $0 and the cost of replacement heifers was $750, the cost of raising heifers from enrollment to calving was lesser for the CONV treatment than the SSEarly treatment, but SSLate treatment did not differ from CONV and SSEarly treatments. When the values of a 1-d-old female calf ≥$130 and 1-d-old male calf ≥$30 and the cost of replacement ≥$1,000, no differences were observed among treatments in the cost from enrollment to calving. We conclude from this experiment that the P/AI with sex-sorted semen is not improved when insemination is delayed by approximately 12 h.

Technical note: Validation of a system for monitoring individual behavior of Holstein cows.

The objectives of the 2 studies reported herein were to validate the accuracy of an automated monitoring device (AMD) to detect side lying, resting, activity, rumination, eating, walking, and panting in nonlactating and lactating dairy cows. Additionally, we aimed to determine whether the total time per cow-state recorded by the AMD within a 30-min interval corresponds to the total time per cow-state recorded simultaneously by visual observation. Study personnel (n = 2) observed pregnant nonlactating Holstein cows (n = 10) for 30 min in the morning and 30 min in the afternoon for 6 consecutive days and recorded continuously each cow-state. In study 2, study personnel (n = 2) observed lactating Holstein cows (n = 10) for 30 min in the morning and 30 min in the afternoon for 6 consecutive days. In both studies, cow-state was recorded every second, and within 1 min, the most prevalent cow-state was considered to be the behavior presented by the cow during that interval. Using the observer as the gold standard, test characteristics were calculated for the minute-by-minute interval analyses. For the 30-min interval analyses, the concordance correlation coefficient (pc) and the coefficient of determination (R2) between the total minutes for each cow-state recorded by the observer and the AMD were calculated. In study 1, for the minute-by-minute interval analyses, test characteristics were high for rumination (≥90.1%) and eating (≥73.8%), moderate for resting (≥62.9%), but negligible for medium activity (≥17%). For the 30-min interval analyses, the correlations between the total time of visual observations compared with the total time recorded by AMD for rumination (R2 = 0.97, pc = 0.98) and eating (R2 = 0.91, pc = 0.94) were very high, for resting (R2 = 0.77, pc = 0.79) was high, and for medium activity (R2 = 0.41, pc = 0.41) was low. In study 2, for the minute-by-minute interval analyses, test characteristics were high for rumination (≥79.4%), eating (≥74.2%), and resting (≥73.0%), but they were low for panting (≥31.3%) and negligible for medium activity (≥22.2%). For the 30-min interval analyses, the correlations were similar to study 1 (rumination: R2 = 0.85, pc = 0.91; eating: R2 = 0.95, pc = 0.97; resting: R2 = 0.84, pc = 0.90; medium activity: R2 = 0.44, pc = 0.57; and panting: R2 = 0.21, pc = 0.42). In summary, the AMD used in this study provided accurate data regarding resting, rumination, and eating of pregnant nonlactating and lactating Holstein cows.

Effect of estrous detection strategy on pregnancy outcomes of lactating Holstein cows receiving artificial insemination and embryo transfer.

Objectives of the current experiment were to evaluate the effects on reproductive performance of adding an automated estrous detection (AED) device to the reproductive management of Holstein cows. In addition, we aimed to determine whether the AED device would equally influence the reproductive performance of cows receiving artificial insemination and those receiving embryo transfer. Cows (n = 1,244) were observed daily for estrous detection by trained farm personnel with the aid of a tail head mounting device. Cows (n = 641) enrolled in the AED treatment were fitted with a neck-mounted automated estrus detection device, and cows enrolled in the control (CTRL, n = 603) treatment were not fitted with the AED device. Cows not detected in estrus by 54 ± 3 DIM received 1 injection of PGF2α, and those not detected in estrus by 68 ± 3 DIM were enrolled in an ovulation synchronization protocol. The hazard of first service tended to be affected by treatment [CTRL: referent, AED: adjusted hazard ratio (AHR) = 1.11, 95% confidence interval (CI) = 0.98, 1.25], and we determined a tendency for the AED treatment to reduce the proportion of cows receiving the first service at fixed time (39.7 ± 5.7 vs. 45.5 ± 5.8%). After the first service, high-producing cows enrolled in the AED treatment were more likely to be pregnant (19.1 ± 2.4 vs. 31.8 ± 3.0%), but no differences between the AED and CTRL treatments were observed among low-producing cows (24.9 ± 2.9 vs. 24.7 ± 2.9%). The hazard of second service was affected by treatment (CTRL: referent, AED: AHR = 1.22, 95% CI = 1.01, 1.47), and the AED treatment reduced the proportion of cows receiving the second service at fixed time compared with the CTRL treatment (15.7 ± 2.2 vs. 21.9 ± 2.5%). After the second service, the AED treatment tended to increase the proportion of cows pregnant (31.0 ± 3.0 vs. 24.9 ± 2.6%) and tended to reduce the proportion of cows that lost pregnancy between the first and second pregnancy exams (9.7 ± 3.3 vs. 16.7 ± 4.6%). The interaction between treatment and type of service did not affect percentage of cows pregnant and pregnancy loss to the first and second services. The hazard of pregnancy was affected by the interaction between treatment and milk yield, in that cows with above the median milk yield in the AED treatment became pregnant at a faster rate than CTRL cows, but no difference between treatments was observed among cows with milk yield below the median. Cows with above the median milk yield had shorter duration of estrus and were less likely to have activity peak at estrus ≥89 (0 = minimum, 100 = maximum). The current experiment suggests that AED devices may improve reproductive performance not only by increasing service rates but also by improving accuracy of estrous detection. According to the current experiment, high-producing cows may benefit most from the addition of AED devices to reproductive management.

Estrous characteristics and reproductive outcomes of Holstein heifers treated with 2 prostaglandin formulations and detected in estrus by an automated estrous detection or mounting device.

Dinoprost tromethamine (DIN), a molecule similar to endogenous PGF2α, has a half-life of approximately 9 min. Cloprostenol sodium (CLO), a synthetic analog of PGF2α, has a half-life of approximately 3 h. We hypothesized that treatment of Holstein heifers with CLO would improve estrous detection rate, estrous characteristics, service rate, and overall reproductive performance compared with DIN. Currently in the United States, heifers are largely inseminated based on signs of estrus, which is detected visually or with the aid of mounting detection devices (MD). Automated estrous detection devices (AED) are becoming more accessible to producers, but it is not clear whether they present advantages in the reproductive management of heifers. Therefore, we hypothesized that the use of an AED would improve service and pregnancy rates compared with detection of estrus with the aid of a MD. Holstein heifers (n = 1,019) were enrolled in the experiment at 10 to 11 mo of age, when they were fitted with a Heatime HR LD System (SCR Ltd., Netanya, Israel). At 12 mo of age, we paired heifers according to estrous cycle phase and randomly assigned them to treatments in a 2 × 2 design: PGF2α formulation (CLO vs. DIN) and estrous detection treatment (AED vs. MD). Heifers in the AED treatment were detected in estrus only by the Heatime HR LD System, whereas heifers in the MD treatment were detected in estrus only by the Kamar Heatmount Detector (Kamar Products Inc., Zionsville, IN). Treatments with the same PGF2α formulations were repeated 14 d after the first treatment if heifers had not been detected in estrus. A sub-group of heifers had blood sampled on the day of PGF2α treatment and within 24 h of onset of estrus to determine progesterone and estradiol concentrations. Treatment with CLO reduced the progesterone concentration within 24 h of onset of estrus compared with DIN (0.04 ± 0.01 vs. 0.11 ± 0.01 ng/mL). Among heifers in mid diestrus on the day of PGF2α treatment, CLO reduced the interval to estrus compared with DIN (72.0 ± 2.2 vs. 82.4 ± 2.4 h). Prostaglandin F2α formulation and estrous detection treatment did not affect pregnancy to the first service. The interval between the first and second services tended to be reduced for the AED treatment compared with the MD treatment (24.4 ± 0.5 vs. 25.7 ± 0.6 d). Prostaglandin F2α formulation and estrous detection treatment did not affect the hazard of pregnancy. Although CLO treatment may shorten the interval to estrus in heifers at mid diestrus compared with DIN, PGF2α formulation did not affect reproductive performance. In the current experiment, no advantages in reproductive performance were observed when estrous detection was based on an AED compared with a MD.

Genomic merit for reproductive traits. I: Estrous characteristics and fertility in Holstein heifers.

Genetic selection of dairy cattle in the United States has included reproductive traits (daughter pregnancy rate, DPR; heifer conception rate, HCR), which is believed to have partly contributed to halting the decline in reproductive performance. The objectives of the current study were to evaluate the association among genomic merit for DPR (GDPR) and HCR (GHCR) with estrous characteristics measured by an automated device. Holstein heifers (n = 1,005) were genotyped at 2 mo of age and were classified into quartiles (Q1 = lowest, Q4 = highest) according to the GDPR and GHCR values of the study population. At 10 to 11 mo of age, heifers were fitted with a collar that recorded activity and rumination and determined the occurrence of estrus according to changes in activity and rumination compared with the individual's baseline values. Estrous characteristics of spontaneous estruses (SPE) and PGF2α-synchronized estruses (PGSE) were recorded. Heifers had their estrous cycle synchronized with PGF2α and following detection of estrus received either artificial insemination or embryo transfer according to the herd's genetic selection program. Heifers in Q2 (17.7 ± 0.3 h) of GHCR tended to have longer SPE than heifers in Q4 (16.7 ± 0.3 h). The interaction between GDPR and GHCR was associated with the likelihood of activity peak (0 = no estrus, 100 = maximum activity) ≥80 at SPE because, among heifers in Q3 and Q4 of GHCR, those in Q1 of GDPR were less likely to have an activity peak ≥80. Heifers in Q1 and Q2 of GDPR had reduced hazard of estrus within 7 d of the first PGF2α treatment compared with heifers in Q4 of GDPR. Heifers in Q1 (16.1 ± 0.4 h) of GDPR had shorter PGSE than heifers in Q2 (17.6 ± 0.4 h) and Q4 (17.4 ± 0.4 h) and tended to have shorter PGSE than heifers in Q3 (17.4 ± 0.4 h). Rumination nadir on the day of PGSE was greater for heifers in Q1 (-30.1 ± 0.9 min/d) of GDPR compared with heifers in Q4 (-33.7 ± 0.9 min/d). Among heifers receiving only artificial insemination, those in Q1 of GHCR (adjusted hazard ratio = 0.65; 95% confidence interval = 0.48-0.88) became pregnant at a slower rate than heifers in Q4. Genomic merit for HCR was negatively associated with SPE but tended to be positively associated with hazard of pregnancy, whereas GDPR was positively associated with PGSE and hazard of estrus. Selection of dairy cattle for DPR and HCR may improve reproductive performance through different pathways, namely estrous characteristics and pregnancy establishment.

Genomic merit for reproductive traits. II: Physiological responses of Holstein heifers.

Fertility traits were recently added to the evaluation of genetic merit, allowing for the selection of Holstein cattle with improved reproductive performance. In the current study, we investigated the associations among genomic merit for daughter pregnancy rate (GDPR) and heifer conception rate (GHCR) and physiological responses during proestrus and diestrus. Holstein heifers (n = 99) were classified based on GDPR [high = 3.26 ± 0.76 (1.6 to 5.3), n = 48; low = -0.17 ± 0.75 (-1.8 to 1.0), n = 51] and GHCR [high = 2.75 ± 0.77 (1.5 to 5.5), n = 49; low = 0.06 ± 0.67 (-2.1 to 1.2), n = 50]. Heifers were fitted with an automated estrous detection device, were treated with PGF2α for synchronization of estrus, and received either artificial insemination or embryo transfer at detected estrus. Blood was sampled at the time of PGF2α treatment, within 24 h of the onset of estrus (d 0), and on d 7, 14, 19 ± 2, 28, and 35. Blood samples from all heifers were analyzed for concentrations of estradiol (d 0) and progesterone (on the day of PGF2α treatment and d 0, 7, and 14). Blood samples from heifers pregnant on d 38 ± 3 were analyzed for concentrations of progesterone (d 0, 7, 14, 19 ± 2, 28, and 35), pregnancy-specific protein B (d 19 ± 2, 28, and 35), and insulin-like growth factor 1 (d 0, 7, 14, 19 ± 2, 28, and 35). Expression of mRNA for interferon-stimulated gene 15 in peripheral leukocytes isolated from blood collected on d 19 ± 2 was determined. Ovaries were scanned by ultrasound daily from d 0 to 4 or until ovulation was detected. Heifers with low GHCR tended to be less likely to be detected in estrus (78.0 vs. 91.8%). Estradiol concentration on d 0 was greater for heifers with high GDPR (4.53 ± 0.23 vs. 3.79 ± 0.23 pg/mL). The ovulatory follicle was larger for heifers with high GDPR (16.28 ± 0.33 vs. 14.55 ± 0.35 mm), whereas heifers with high GHCR tended to have smaller ovulatory follicles (15.00 ± 0.31 vs. 15.83 ± 0.37 mm). Heifers with high GDPR tended to be more likely to ovulate within 96 h of the onset of estrus (90.7 vs. 75.0%). Among heifers pregnant on d 38 ± 3, GDPR and GHCR were not associated with mRNA expression for interferon-stimulated gene 15. Heifers with high GDPR had greater concentration of pregnancy-specific protein B from d 28 to 35 (3.03 ± 0.15 vs. 2.48 ± 0.1 ng/mL). Heifers with high GHCR tended to have greater insulin-like growth factor 1 concentration from d 7 to 35 (108.0 ± 3.2 vs. 97.7 ± 4.2 ng/mL). Our results suggest that selection for Holstein cattle for GDPR may have positive effects on reproductive performance through changes in ovarian follicle development and steroidogenesis. Although selection of Holstein cattle for GHCR may negatively affect estrous expression by affecting ovarian follicle growth, selection for GHCR may improve reproductive performance by altering the somatotropic axis.

Association between body condition score change during the dry period and postpartum health and performance.

The objectives of the current study were to determine the association between body condition score change during the dry period (ΔBCS) and postpartum health and reproductive and productive performance of Holstein cows. Data from 16,104 lactations from 9,950 parous cows from 2 dairies located in the San Joaquin Valley of California were used. Within dairy, cows were scored for body condition at dry off and parturition by the same herd workers, who were trained by veterinarians from the Veterinary Medicine Teaching and Research Center of the University of California Davis. Cows were classified as having excessive loss of BCS (ΔBCS ≤-0.75; n = 1,604), moderate loss of BCS (ΔBCS = -0.5 to -0.25; n = 6,430), no change in BCS (ΔBCS = 0; n = 4,819), and gained BCS (ΔBCS ≥0.25; n = 3,251). Data regarding morbidity, mortality, and reproductive and productive performance were recorded until 305 d postpartum or until cows were dried off or left the herd. Loss of BCS during the dry period was associated with greater incidence of uterine disease and indigestion. Additionally, loss of BCS during the dry period was associated with greater likelihood of treatment with antimicrobials, anti-inflammatories, and supportive therapy. Loss of BCS during the dry period was associated with reduced likelihood of pregnancy after the first and second postpartum inseminations. Cows that gained BCS during the dry period had greater yield of milk, fat, and protein and had reduced somatic cell linear score in the subsequent lactation. In the current study, loss of BCS during the dry period was a predisposing factor associated with health disorders and reduced productive and reproductive performance in Holstein cows.

Effects of intrauterine infusion of Escherichia coli lipopolysaccharide on uterine mRNA gene expression and peripheral polymorphonuclear leukocytes in Jersey cows diagnosed with purulent vaginal discharge.

The objectives of the current experiment were to investigate the effects of intrauterine treatment of cows with purulent vaginal discharge (PVD) using lipopolysaccharide (LPS) from Escherichia coli on uterine mRNA expression of genes related to inflammatory responses, peripheral polymorphonuclear leukocyte (PMN) function, hematological parameters, and blood concentrations of cortisol, haptoglobin, and progesterone (P4). Jersey cows (n = 3,084) were examined for PVD at 35 ± 6 d postpartum using the Metricheck device (Simcro, Hamilton, New Zealand). At examination, 310 cows had PVD (10.1%), but to ensure proper collection and processing of samples, 267 cows were used in this experiment. Cows were balanced for lactation number, body condition score, and milk yield, and randomly assigned to the control treatment [intrauterine infusion of 20 mL of phosphate-buffered saline (PBS); n = 87] or to receive intrauterine infusion of 20 mL of PBS containing 150 µg (LPS150; n = 91) or 300 µg (LPS300; n = 89) of E. coli LPS. Uteri were biopsied in a subgroup of cows at 6 h after infusion and in another subgroup of cows at 24 h after infusion. Peripheral PMN expression of adhesion molecules (L-selectin and MAC-1) and phagocytosis and oxidative burst were evaluated at 0, 2, and 6 h after infusion. Blood sampled 0, 2, 6, 24, 48, and 168 h after infusion was used for complete hemogram and to determine concentrations of cortisol, haptoglobin, and P4. Treatment did not affect uterine mRNA expression of adhesion molecules [endothelial leukocyte adhesion molecule (E-selectin), intracellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1)], cytokines (tumor necrosis factor-α, IL-1ß, IL-6, IL-8, and IL-10), and toll-like receptor-4. Treatment did not affect PMN expression of L-selectin, but intensity of expression of MAC-1 was higher for LPS150 cows than PBS cows, and tended to be higher in LPS150 than LPS300 cows. Furthermore, a greater percentage of PMN from LPS300 cows were positive for phagocytosis and oxidative burst compared with PBS and LPS150 cows. No effects were observed of treatment on hematological parameters and concentrations of cortisol, haptoglobin, and P4. These observations suggest that intrauterine infusion of E. coli LPS moderately stimulates peripheral PMN function, but further research is needed to better understand the immunomodulatory effects of LPS in the uterus of cows with PVD.

Effects of intrauterine infusion of Escherichia coli lipopolysaccharide on uterine health, resolution of purulent vaginal discharge, and reproductive performance of lactating dairy cows.

The objectives of the current experiment were to evaluate the effects of intrauterine infusion of Escherichia coli lipopolysaccharide (LPS) in cows diagnosed with purulent vaginal discharge (PVD) on intrauterine cell population, resolution of PVD, uterine health, and reproductive performance. Jersey cows (n = 3,084) were examined using the Metricheck device to diagnose PVD at 35 ± 6 d postpartum. Purulent vaginal discharge was defined as the presence of purulent (≥50% pus) discharge detectable in the vagina. Of the 310 cows positive for PVD, 267 cows were enrolled in the current experiment. To ensure proper timing of treatment and collection of samples, only 9 PVD-positive cows were treated per day. Selected cows were balanced at 35 ± 6 d postpartum for lactation number, body condition score, and milk yield and were randomly assigned to receive an intrauterine infusion of 20 mL of phosphate-buffered saline (PBS; control, n = 87), 20 mL of PBS with 150 µg LPS (LPS150, n = 91), or 20 mL of PBS with 300 µg of LPS (LPS300, n = 89). Uterine cytology was performed immediately before treatment and 1, 2, and 7 d after treatment to evaluate the effect of LPS treatment on intrauterine cell population. Cows were examined with the Metricheck device at 7 and 28 d after treatment to evaluate the effects of treatment on resolution of PVD. Reproductive status was recorded up to 200 d postpartum. Cows diagnosed with PVD had greater incidence of twinning, dystocia, retained placenta, and metritis after calving than cows without PVD. Count of polymorphonuclear leukocytes (PMNL) in uterine cytology 1, 2, and 7 d after intrauterine infusion was not statistically different among treatments. From d 0 to 1, however, PMNL count in uterine cytology of PBS cows increased by 5%, whereas the PMNL count in uterine cytology of LPS150 and LPS300 cows increased by 54 and 48%, respectively. Treatment did not affect the likelihood of cows being diagnosed with PVD 7 and 28 d after intrauterine infusion. Cows without PVD and LPS150 cows were more likely to be pregnant after the first postpartum AI than PBS cows. After the second postpartum AI, cows without PVD were more likely to be pregnant than PBS and LPS300 cows. Hazard of pregnancy up to 200 d postpartum was decreased for PBS and LPS300 cows compared with cows without PVD, and it tended to be decreased for LPS150 cows compared with cows without PVD. Intrauterine treatment with 150 µg of E. coli LPS of cows diagnosed with PVD improved likelihood of pregnancy after the first postpartum AI, but further research is needed to elucidate the mechanism by which LPS treatment improved fertility.

Social stressors and their effects on immunity and health of periparturient dairy cows.

Management practices during the periparturient period have been the focus of much research recently because during this period immune function, metabolism, and health of cows are severely challenged. Responses to stress are often classified as behavioral, immunological, neuroendocrine, and autonomic. In production systems, understanding all facets of stress response is important to correctly predict the consequences of stressors to the health and performance of animals and to prevent costly managerial changes that have minimal effect on animal well-being and performance. Common social stressors faced by periparturient animals are regrouping, overstocking, and for nulliparous animals, commingling with parous animals. In conventional dairies, feeding strategies during the periparturient period often require several group changes during the most challenging period of an animal's life. Traditional weekly regrouping of prepartum cows increases competitive behavior at the feed bunk but it does not affect immune and metabolic responses, health and production, as long as stocking density is not overwhelming, and nulliparous and parous animals are housed separately. Stocking density of prepartum animals may be overlooked because these are nonproductive animals. Severe overstocking (200% of feeding space) of commingled nulliparous and parous pregnant animals produces neuroendocrine and metabolic changes. On the other hand, when prepartum nulliparous and parous animals are housed separately, stocking densities of up to 120% do not seem to affect innate and adaptive immunity, metabolic responses, milk yield, and reproductive performance, despite increasing negative behavior among cows. In recent experiments, when animals were ranked based on feed bunk displacement, dominant animals were more likely to be diagnosed with metritis than subordinate animals. Importantly, dominant animals with large number of interactions with pen mates (displacement at the feed bunk) were considerably more likely to be diagnosed with uterine diseases (retained placenta and metritis) and to be removed from the herd within 60d postpartum. Much has been learned about behavioral responses of cows to stressful conditions, but our understanding of neuroendocrine and immune responses to such conditions is somewhat limited. A multidisciplinary approach to research that encompasses several responses to stress and biological functions is critical.

Short communication: Plasma progesterone concentration and ovarian dynamics of lactating Jersey cows treated with 1 or 2 intravaginal progesterone inserts.

The objectives of the current experiment were to determine circulating progesterone concentrations and ovarian follicle development of lactating Jersey cows treated with 1 or 2 controlled internal drug release (CIDR) insert containing 1.38 g of progesterone during proestrus. Cows were enrolled in the experiment at 34 ± 3 d in milk and were paired by parity, body condition score, body weight, and milk yield. Estrous cycles were presynchronized with an injection of GnRH concurrent with a new CIDR insert (study d -7) and 2 injections of PGF2α given 5 and 6 d after the GnRH injection (study d -2 and -1, respectively). Cows assigned to the 1CIDR treatment (n=30) or 2CIDR treatment (n=30) received 1 and 2 CIDR inserts, respectively, from study d 0 through 7. Control cows (n=10) did not receive further treatment. On study d -2 and daily from study d 0 through 7, ovaries were examined by transrectal ultrasound and blood samples were collected for determination of progesterone. On study d 7, CIDR inserts were removed after ultrasound exam and blood sample collection. Progesterone concentration from study d 0 through 7 was greatest for 2CIDR cows (2.17 ± 0.09 ng/mL), followed by 1CIDR cows (1.37 ± 0.10 ng/mL) and control cows (0.62 ± 0.21 ng/mL). The interaction between treatment and study day affected progesterone concentration from study d 0 through 7. The average increase in progesterone concentration from study d 1 through 7 was 0.80 ng/mL for 1CIDR and 1.72 ng/mL for 2CIDR cows compared with control cows. The percentage of cows that ovulated between study d 0 and 7 was greatest for control cows (80%), but it did not differ between 1CIDR (12%) and 2CIDR (3.7%) cows. Growth of class III follicles (10-17 mm) identified on study d 0 was affected by treatment because 1CIDR cows had larger class III follicles than 2CIDR cows on study d 5, 6 and 7. A larger proportion of control cows developed a new follicular wave between study d 0 and 7 (control=60.0%, 1CIDR=12.0%, 2CIDR=7.4%). Treatment of lactating Jersey cows with 1 and 2 CIDR inserts resulted in a 1 and 2 fold increase, respectively, in circulating progesterone concentration. Growth class III follicles from cows treated with 2 CIDR inserts was reduced compared with untreated cows and cows treated with 1 CIDR insert.