Automated Activity Monitoring Research Articles

Comparison of two intravaginal progesterone-releasing devices in lactating Holstein cows synchronized with a 5-d GnRH-based timed-AI protocol

The objective of the study was to compare the effectiveness of CIDR vs. PRID-Delta devices for use in a 5-day Ovsynch protocol for TAI in lactating Holstein cows that were either not in estrus after the end of the voluntary waiting period or non-pregnant and not returning to estrus following the previous AI. Cows fitted with a collar-mounted automated activity monitoring system (Alta Cow Watch) were subjected to a standard 5-d Ovsynch protocol [100 μg of gonadorelin (GnRH) on Day 0 and 500 μg of cloprostenol on Days 5 and 6] and allocated randomly to receive either an intravaginal device containing 1.35 g (CIDR; n = 304) or 1.55 g (PRID ® DELTA; n = 304) of progesterone between Day 0 and 5. All cows received a second administration of GnRH at approximately 56 h and timed-AI (TAI) 72 h after intravaginal device removal. Inseminations were done using conventional frozen-thawed semen. Estrus events prior to TAI were recorded and transrectal ultrasonography was done on Day 0 to determine presence of a corpus luteum (CL) and 33 and 61 d post-TAI, respectively, to diagnose and confirm pregnancy. Cows had an average of 2.2 lactations, 124.3 days in milk, and a milk yield of 43.6 kg/d at enrollment. The overall percentage of cows with a CL at initiation of treatment was 68.8 % and did not differ between treatment groups. Cows with a CL had greater pregnancy per AI (P/AI) at 33 and 61 d post-TAI than cows without a CL (P < 0.01; 46.9 and 42.3 % vs. 32.1 and 27.4 %, respectively). The overall percentage of cows that expressed estrus prior to TAI was 24.8 % and did not differ between treatment groups; however, estrus expression prior to TAI affected P/AI at 33 and 61 d post-TAI (P < 0.01; 53.6 and 49.0 % vs. 38.5 and 33.9 % for those expressing or not expressing estrus, respectively). Pregnancy per AI at 33 d post-TAI tended to differ between treatment groups (P = 0.08; 46.1 vs. 38.5 % for PRID and CIDR groups, respectively) and P/AI at 61 d post-TAI was greater (P < 0.01) for PRID-treated cows (43.8 %) compared to CIDR-treated cows (31.6 %). Thus, PRID-treated cows had lower pregnancy loss than CIDR-treated cows (P < 0.01; 5.0 vs. 17.9 %). Also, treatment with a PRID tended (P = 0.08) to result in fewer twin pregnancies (7.9 vs. 14.5 % for PRID and CIDR treated cows, respectively). In conclusion, lactating dairy cows subjected to a 5-d Ovsynch TAI protocol plus a PRID-Delta had greater P/AI at 61 d post-TAI, lower pregnancy loss between 33 and 61 d post-TAI, and fewer twin pregnancies compared to cows subjected to a 5-d Ovsynch protocol plus a CIDR.

Machine Learning to Predict Pregnancy in Dairy Cows: An Approach Integrating Automated Activity Monitoring and On-Farm Data.

Automated activity monitoring (AAM) systems are critical in the dairy industry for detecting estrus and optimizing the timing of artificial insemination (AI), thus enhancing pregnancy success rates in cows. This study developed a predictive model to improve pregnancy success by integrating AAM data with cow-specific and environmental factors. Utilizing data from 1,054 cows, this study compared the pregnancy outcomes between two AI timings-8 or 10 h post-AAM alarm. Variables such as age, parity, body condition, locomotion, and vaginal discharge scores, peripartum diseases, the breeding program, the bull used for AI, milk production at the time of AI, and environmental conditions (season, relative humidity, and temperature-humidity index) were considered alongside the AAM data on rumination, activity, and estrus intensity. Six predictive models were assessed to determine their efficacy in predicting pregnancy success: logistic regression, Bagged AdaBoost algorithm, linear discriminant, random forest, support vector machine, and Bagged Classification Tree. Integrating the on-farm data with AAM significantly enhanced the pregnancy prediction accuracy at AI compared to using AAM data alone. The random forest models showed a superior performance, with the highest Kappa statistic and lowest false positive rates. The linear discriminant and logistic regression models demonstrated the best accuracy, minimal false negatives, and the highest area under the curve. These findings suggest that combining on-farm and AAM data can significantly improve reproductive management in the dairy industry.

Access to an outdoor open pack promotes estrus activity in dairy cows.

Dairy cows have a partial preference to access an outdoor deep-bedded pack, but the effects of continuous access to an outdoor area on estrous behaviors has not been studied. Our objective was to investigate if access to an outdoor open deep-bedded pack improves the expression of estrus behaviors. We enrolled 60 lactating Holstein cows directly after calving and followed them each for 12 weeks. Cows were housed in a single freestall pen holding 36 cows at a time, with a dynamic group composition. Half of the cows were randomly assigned to the OUTDOOR treatment; these cows had access to an outdoor open pack via an automated selection gate. INDOOR cows were housed together with OUTDOOR cows but were not allowed outdoor access. All cows were fitted with an automated activity monitor (AAM) 21 ± 3 d before expected calving date. Estrous behaviors (i.e., standing to be mounted and mounting behaviors) were continuously monitored using video, and the intensity of mounting (i.e., the number of standing to be mounted and other mounting behaviors per hour) was calculated per estrus event per cow. Temperature and humidity were monitored by data loggers indoors, and these data were used to calculate the Temperature Humidity Index (THI). Following an alert from the AAM, cows were checked to detect the presence of a dominant preovulatory follicle and an absence of a mature corpus luteum (CL) by rectal ultrasonography following milking, as well as 7 d thereafter to confirm ovulation by the presence of a new CL. A total of 94 estrus events were used in the final analysis. INDOOR cows tended to have a lower mounting intensity with increasing indoor THI, but no such effect was noted for OUTDOOR cows. The total number of cows in estrus positively influenced mounting intensity. OUTDOOR cows had a longer duration of estrus, as measured by the automated monitors, compared with INDOOR cows (12.4 ± 0.7 h versus 9.9 ± 0.8 h). Estrus event number and the total number of cows in estrus were both positively associated with estrus duration. These results indicate that access to an outdoor pack tended to increase mounting behavior for freestall housed dairy cows, especially during periods of elevated THI. We conclude that providing dairy cows access to an outdoor area can help with estrus detection and may thus help improve the reproductive programs on dairy farms.

Horário da inseminação artificial na taxa de prenhez das vacas Holandesas usando monitoramento automatizado de atividades

ABSTRACT: This study evaluated the probability of pregnancy and associated factors for two times artificial inseminations (AI), 8 or 10 hours after automated activity monitoring (AAM) alarm on the first postpartum AI of 1,054 Holstein dairy cows. The estrus was synchronized by prostaglandin or estradiol-progesterone program. Stepwise logistic regression was performed to analyze the probability of pregnancy, and associated factors (activity, estrus intensity, parity, peripartum health, retained placenta, postpartum vaginal discharge, and season). The highest pregnancy rates were obtained with multiparous animals, inseminated ten hours after the AAM alarm, in the fall or winter season, with a high activity peak and estrus intensity (P &lt; 0.05). Peripartum diseases, retained placenta, and postpartum vaginal discharge negatively influenced the pregnancy rate, regardless of parity. Thus, the optimization of AAM models by including on-farm measures like parity, peripartum health history, and environmental conditions may favor the correct identification of estrus and improve the AAM alarm regarding the ideal moment for AI, increasing the reproductive performance in dairy cows.

Efficacy of an automated technology at detecting early postpartum estrus events: Can we detect resumption of cyclicity?

The objective of this observational study was to evaluate the efficacy of a neck-mounted automated activity monitor (AAM) at detecting early postpartum resumed ovarian cyclicity. A total of 192 lactating cows (primiparous = 73 and multiparous = 119) were enrolled in this study. Cows were continuously monitored by a neck-mounted AAM early postpartum (7 to 30 d in milk; DIM). Calving was classified as assisted (forced extraction of a calf) or unassisted (normal calving). Retained fetal membrane, metritis, hyperketonemia, clinical mastitis, and milk production were recorded. Cows were classified as healthy (i.e., no disease events) or sick (i.e., any disease event). Estrus events were alerted by the AAM using a proprietary algorithm set by the AAM company. Blood samples, from the coccygeal vein, were collected at 15, 18, 21, 24, 28, and 30 DIM for progesterone (P4) analysis. Resumption of cyclicity was considered when P4 concentration was ≥1 ng/mL on any collection day. Cows were considered anovular when P4 concentration was <1 ng/mL on all collection days. Cows were classified as true positive: P4 ≥ 1 ng/mL and at least one estrus alert; false positive: P4 < 1 ng/mL and at least one estrus alert; true negative: P4 < 1 ng/mL and no estrus alerts; and false negative: P4 ≥ 1 ng/mL and no estrus alerts. Statistical analyses were performed by frequency distribution and mixed effects logistic regression procedures on SAS (SAS Institute Inc.). The specificity, sensitivity, accuracy, and positive predictive value of the sensor to detect cows that had resumed cyclicity were 84.0%, 34.1%, 52.1%, and 79.2%, respectively. Out of the 192 cows, 35.9% (69/192) were anovulatory and 37.5% (72/192) had no estrus events between 7 to 30 DIM. Healthy cows were more likely to resume cyclicity in early lactation compared with cows that were sick (78.3 ± 1.9 vs. 32.8 ± 3.1%, respectively) independent of parity. In conclusion, the sensor had a high specificity for detecting anovular cows, but it had lower sensitivity, and thus was not effective at detecting cyclic cows, perhaps due to silent ovulation early postpartum.

Association between genomic daughter pregnancy rate and expected milk production on the resumption of estrus behavior in Holstein cattle

The objective of this observational study was to evaluate estrous expression at the first estrus occurring between 7 to 30 d in milk (DIM), as detected by an automated activity monitor (AAM), and its association with genomic daughter pregnancy rate (GDPR) and genomic expected milk production (GEM) in lactating dairy cows. A total of 4,119 lactations from 2,602 Holstein cows were included. Cows were enrolled as first lactation (n = 1,168), second lactation (n = 1,525) and third and greater lactation (n = 1,426). Hair samples were collected from the tail switch, and cows were genotyped using an SNP platform (Clarifide, Zoetis, São Paulo, SP, Brazil). Postpartum cows were examined daily by the farm personnel from calving until 10 DIM. Calving was classified as assisted (forced calf extraction) and unassisted (normal calving). Retained fetal membranes (RFM), hyperketonemia (KET), and left displaced abomasum (LDA) were also recorded. Mean GDPR (± SD) was -0.29 ± 1.4, and the intensity and duration of the first estrus event was 15.9 ± 13.1 x-factor (intensity unit measurement) and 11.1 ± 3.8 h, respectively. Cows that had greater GDPR had greater intensity and longer duration of estrus at the alert, independent of parity. Overall resumption of estrous expression, between 7 to 30 DIM, was 41.2% (1,695/4,119), where 58.8% (2,424/4,119) did not have an estrus event, 31.0% (1,274/4,119) of cows had one event of estrus, and 10.2% (421/4,119) of cows had 2 or more events of estrus early postpartum. Mean DIM (± SD) at first estrus event, detected by the AAM, was 19.4 ± 4.4 d. Days in milk at first event for cows with one event was 20.7 ± 1.6 d and 15.9 ± 3.1 d for cows with 2 or more events of estrus. First lactation cows were more likely to have an estrus event early postpartum when compared with second and third and greater lactation cows (45.2 ± 1.4% [530/1168] vs. 41.6 ± 1.3% [636/1525] vs. 37.2 ± 1.3% [529/1426], respectively). There was an interaction of parity and GDPR on the proportion of cows demonstrating an early postpartum estrus. There was no difference in the proportion of cows with an early postpartum estrus between those with assisted or unassisted calving, RFM, or LDA. However, cows that had KET were less likely to have an alert early postpartum when compared with cows that did not have KET. Mean genomic expected milk production (± SD) was 256.8 ± 600.1 kg. There was no interaction between GEM and parity on estrous expression (i.e., intensity and duration). There was no interaction between GEM and GDPR on the proportion of estrus early postpartum.

Association between Prepartum Alerts Generated Using a Commercial Monitoring System and Health and Production Outcomes in Multiparous Dairy Cows in Five UK Herds.

Identifying cows that are at greater risk for disease prior to calving would be a valuable addition to transition management. Prior to the commercial release of software features in an automated behavioral monitoring system, designed to identify cows in the dry period at greater risk of disease postpartum, a retrospective analysis was carried out in five dairy herds to evaluate whether the software could identify prepartum cows that subsequently received health treatments postpartum and whether prepartum alerts (transition alerts) are associated with a reduction in milk production in the subsequent lactation. Herd management and production records were analyzed for cows receiving treatment in the first 21 d of lactation (days in milk, DIM) for clinical mastitis, reproductive tract disease (metritis, retained fetal membranes), metabolic disease (hypocalcemia, ketosis and displaced abomasum) and for cows exiting the herd by 60 DIM. Data was gathered for 986 cows, 382 (38.7%) of which received a transition alert and 604 (61.3%) that did not. During the first 21 DIM 312 (31.6%) cows went on to receive a disease treatment, of these 51.9% (n = 162/312) were transition alert cows and 48.1% (n = 150/312) non-transition alert cows, while 8.6% (n = 33/382) alert cows exited the herd by 60 DIM compared to 4.8% (n = 29/604) of cows that did not receive an alert. A cow receiving a transition alert (OR = 1.76, 95% confidence interval (CI) = 1.27-2.44) and increasing parity (OR = 2.03, 95% CI = 1.44-2.86) were both associated with increased risk of receiving a disease treatment in the first 21 DIM. The occurrence of a transition alert was negatively associated with both week 4 milk yield (daily average yield in fourth week of lactation) and predicted 305 d yield. Transition alerts correctly predicted 62.5% (95% CI: 59.3-65.5) of treatments with a sensitivity of 42.4% (95% CI: 37.4-45.5) and a specificity of 75.2% (95% CI: 71.5-78.6). Associations were identified between postpartum health and production outcomes and prepartum behavioral measures from an automated activity monitoring system.

Timing of Artificial Insemination Using Sexed or Conventional Semen Based on Automated Activity Monitoring of Estrus in Holstein Heifers.

Investigations on the optimum timing of artificial insemination (AI) following automated activity monitoring (AAM) depending on different types of semen in heifers are limited and in part show controversial results. Therefore, the objective of this observational study was to determine the association between the timing of AI using different characteristics of estrus (i.e., the onset, peak, and end of estrus) and pregnancy per AI (P/AI) in Holstein heifers. Heifers were fitted with a neck-mounted AAM system and inseminated with frozen conventional and sexed semen. The pregnancy per AI (n = 4159) from 2858 heifers from six commercial dairy farms in Germany inseminated upon the alert of an AAM system was evaluated. Estrous intensity was classified based on peak activity into low (35 to 89 index value) and high (90 to 100 index value). We detected a quadratic association between the interval from the onset of estrus to AI and P/AI (p = 0.02). The greatest P/AI was observed for heifers inseminated from 9 to 32 h after the onset of estrus. The intervals from the peak of activity to AI and the end of estrus to AI were not associated with P/AI (p ≥ 0.05). Heifers inseminated with frozen conventional semen (50.1%) had a greater P/AI compared with heifers inseminated with frozen sexed semen (43.3%; p = 0.03). There were no interactions between the intervals from the onset, peak, or end of estrus to AI or the type of semen and the P/AI (p ≥ 0.05). The pregnancy per AI was not associated with estrous intensity (50.5% for low intensity vs. 53.0% for high intensity; p = 0.37). In conclusion, inseminating heifers between 9 and 32 h after the onset of estrus, as detected by the AAM, optimized the P/AI regardless of semen type.

The effect of progesterone concentrations during superovulation of Holstein heifers in a randomized trial

The aim of this study was to evaluate the effect of different progesterone (P4) concentrations during the follicular growth on the intensity of estrous expression, ovarian response to the superovulatory treatment, and embryo production and quality in superovulated heifers. A total of 63 Holstein heifers were randomly assigned into 2 experimental groups: Low P4 (n = 31) and High P4 (n = 32). Animals received a pre-synchronization protocol followed by a protocol of superovulation that included the allocated P4 treatment. Activity was monitored continuously by an automated activity monitor, and estrus characteristics (maximum intensity and duration) were recorded. Embryo collection was performed 7 d post artificial insemination (AI). Embryos were counted and graded from good or excellent (1) to degenerated (4). The outcomes of interest were: number and diameter of follicles at the time of AI, ovulation success (confirmed 7 d post-AI), time to estrus event, maximum intensity and duration of estrus, number and quality of embryos. Data were analyzed according to the type of outcome variable using logistic, linear, or Poisson regression models. A total of 105 embryos (High P4: n = 42; Low P4: n = 63) were graded for quality. Different P4 levels did not affect the maximum intensity (High P4 = 497.8 ± 23.9%; Low P4 = 542.2 ± 23.5%) or the duration (High P4 = 13.5 ± 1.5 h; Low P4 = 14.3 ± 1.4 h) of estrus. Heifers in the High P4 treatment had greater number of follicles at time of AI (High P4 = 16.6 ± 1.6 follicles; Low P4 = 13.9 ± 1.2 follicles), but with smaller diameter (High P4 = 11.3 ± 0.1 mm; Low P4 = 12.0 ± 0.1 mm) compared with Low P4. High P4 heifers tended to have better embryo quality compared with Low P4 heifers (odds ratio = 1.98; 95% CI = 0.90-4.35). High P4 heifers had less embryos than Low P4 heifers, but this was modified by the CIDR (intravaginal implant of P4) removal to estrus interval (interval 0-21 h: mean ratio = 1.15, 95% CI = 0.42-1.87; interval 22-46 h: mean ratio = 0.58, 95% CI = 0.27-0.96). Although estrous expression was not associated with embryo quality, as the duration and the maximum intensity of estrous expression increased, the number of embryos recovered 7 d post-AI increased (duration: mean ratio = 1.04; 95% CI = 1.03-1.05; maximum intensity: mean ratio = 1.50; 95% CI = 1.42-1.58). In conclusion, P4 during the follicular growth, and intensity of estrus, are playing a role in regulating the quality and the number of embryos produced by superovulated heifers. This study was supported by contributions from Resilient Dairy Genome Project and the Natural Sciences and Engineering Research Council.

Time of insemination in relation to pregnancy rates in beef cattle after oestrus detection with automated activity monitoring system

BackgroundThe timing of artificial insemination is critical to achieve acceptable results in cattle production systems. Over the past 60 years the length and expression of oestrus in dairy cattle has altered. Recent studies have indicated the optimal timing for insemination after the commencement of oestrus may now be earlier than traditional recommendations in beef cattle, as is the case in dairy cattle. The aim of the current study was to evaluate the effect of time from onset of oestrus [as determined by an automated activity monitoring system (AAMS)] to artificial insemination (AI) on pregnancy outcome in Norwegian beef cattle. Five commercial beef suckler herds participated in a cohort study by providing data on the time of AAMS alarm and time of AI. Blood sampling on the day of AI was performed and serum progesterone concentration measured. Pregnancy detection was performed by transrectal ultrasonography and aging of the fetus performed when necessary. A mixed logistic regression model was fitted to study the effect of time from AAMS alarm to AI on pregnancy outcome. Time categories used in the model were < 12 h, 12–24 h, and > 24 h.ResultsAI periods (n = 229) with serum progesterone concentration < 1 ng/mL were available for analysis. Overall pregnancy risk per AI for the whole study period was 65.5%, with an inter-herd variation from 10 to 91%. Median time elapsed from AAMS alarm to AI was 17.75 h. Herd affected pregnancy outcome (P = 0.001), while breed and parity status (heifer/cow) did not. The time category closer to AAMS alarm 0–12 h showed a numerically lower pregnancy risk as compared to the baseline group which had AI 12–24 h after onset of oestrus.ConclusionThis study found no evidence to support a change in the recommended timing of AI in beef suckler cows.

Association of activity and subsequent fertility of dairy cows after spontaneous estrus or timed artificial insemination

The objective of this observational study was to evaluate the association between increased physical activity at first artificial insemination (AI) and subsequent pregnancy per AI (P/AI) in lactating Holstein cows following spontaneous estrus or a timed AI (TAI) protocol. We also wanted to identify factors associated with the intensity of activity increase (PA) captured by automated activity monitors (AAM) and fertility. Two experiments were conducted, in which cows either were inseminated based on the alert of the AAM system (AAM cows) or received TAI following a 7-d Ovsynch protocol (TAI cows) if not inseminated within a farm-specific period after calving. Experiment 1 included 2,698 AI services from AAM cows and 1,042 AI services from TAI cows equipped with the Smarttag Neck (Nedap Livestock Management) from a dairy farm in Slovakia (farm 1). In the second experiment, 6,517 AI services from AAM cows and 1,226 AI services from TAI cows fitted with Heatime (Heatime Pro; SCR Engineers Ltd.) from 8 dairy farms in Germany (farms 2-9) were included. Pregnancy diagnosis was performed on a weekly basis by transrectal ultrasound (farms 1, 3, 7, 8) or by transrectal palpation (farms 2, 4-6, 9). Estrous intensity was represented by the peak value of the change in activity. In experiment 1, PA was categorized into low (x-factor 0-20) and high (x-factor 21-100) PA, and in experiment 2 into low (activity change = 35-89) and high (activity change = 90-100) PA. In TAI cows from both experiments, PA was additionally categorized into cows with no AAM alert. Data were analyzed separately for AAM and TAI cows using multinomial logistic regression models for PA in TAI cows and logistic regression models for PA in AAM cows and P/AI in both groups. In experiment 1, P/AI of AAM cows was greater for AI services performed with conventional frozen semen (57.6%) compared with sexed semen (47.2%), whereas type of semen only tended to be associated with P/AI in TAI cows (54.4% conventional frozen semen vs. 48.9% sexed semen). In experiment 2, P/AI was greater for fresh semen (AAM cows: 44.4% vs. TAI cows: 44.2%) compared with conventional frozen semen (AAM cows: 37.6% vs. TAI cows: 34.6%). In both experiments, pregnancy outcomes were associated with PA. In experiment 1, AAM cows with high PA (55.1%) had greater P/AI than cows with low PA (49.8%). Within TAI cows, cows with no alert (38.8%) had reduced P/AI compared with cows with low (54.2%) or high PA (61.8%). In experiment 2, AAM cows with high PA (45.8%) had greater P/AI compared with cows with low PA (36.4%). Timed AI cows with no alert (27.4%) had decreased P/AI compared with cows with low (41.1%) or high (50.8%) PA. The greatest risk factors for high PA were parity (experiment 1) and season of AI (except for TAI cows from experiment 1). We conclude that high PA at the time of AI is associated with greater odds of pregnancy for both AAM and TAI cows. In both experiments, about 2 thirds of AAM cows (experiment 1: 69.9% and experiment 2: 70.7%) reached high PA, whereas only approximately one-third or less of TAI cows (experiment 1: 37.3% and experiment 2: 23.6%) showed high PA. Although we observed similar results using 2 different AAM systems for the most part, risk factors for high PA might differ between farms and insemination type (i.e., AAM vs. TAI).

Estrous activity and pregnancy outcomes in Holstein heifers subjected to a progesterone based 5-d CO-Synch protocol with or without administration of initial GnRH.

The objectives of this study were to investigate whether estrous activity and its impact on pregnancy outcomes would differ in heifers subjected to a 5d CO-Synch plus progesterone releasing intravaginal device (PRID) protocol with or without an initial GnRH treatment. Holstein Heifers (n=308) were fitted with a collar-mounted automated activity monitoring system approximately 1 week prior to the initiation of the synchronization protocol (Day-7). Heifers were assigned randomly to a 5d CO-Synch plus PRID protocol either with (GnRH; n=154) or without (NGnRH; n=154) an initial administration of 100μg of GnRH at the time of PRID insertion (Day 0). Heifers received a single administration of 500μg of cloprostenol (PGF) at the time of PRID removal (Day 5) and again 24h later (Day 6). Approximately 72h after PRID removal (Day 8), heifers were timed-inseminated (TAI) and concurrently 100μg of GnRH was administered to those not exhibiting estrus. All inseminations were done by one of two technicians using either sex-sorted (n=252) or conventional (n=56) frozen-thawed semen. Transrectal ultrasonography was done on Day 0 to determine ovarian cyclicity and normalcy of the reproductive tract and 30 and 45d post-TAI to determine and confirm pregnancy, respectively. The percentage of heifers determined to be in estrus following PRID removal was greater in the GnRH than in the NGnRH group (94 vs. 82%, respectively; P<0.01). The mean interval from PRID removal to the onset of estrus was shorter for GnRH- than NGnRH-treated heifers (50.8 vs. 59.2h, respectively; P<0.01). Pregnancy per AI (P/AI) at 30d post-TAI tended to be greater for GnRH than NGnRH heifers (68 vs. 59%, respectively; P=0.1). However, P/AI at 45d post-TAI (65 vs. 57%, respectively) and pregnancy loss between 30 and 45d post-TAI (6 vs. 4.5%, respectively) did not differ. The association between the interval from PRID removal to the onset of estrus and P/AI at 30d post-TAI was linearly negative for GnRH heifers; for every 1h increase in the interval from PRID removal to the onset of estrus, the predicted probability of P/AI at 30d post-TAI tended (P=0.08) to be reduced by 2.7%. The association between the interval from PRID removal to the onset of estrus and P/AI at 30d post-TAI was not significant for NGnRH heifers. In addition, the interval from TAI to subsequent estrus, in non-pregnant heifers, was approximately 3d longer for the GnRH than the NGnRH group (20.7 vs. 17.5d, respectively). In summary, the initial GnRH treatment in a 5d CO-Synch plus PRID protocol increased estrus expression and reduced the interval from PRID removal to the onset of estrus in Holstein heifers and tended to increase P/AI at 30d, but did not affect P/AI at 45d post-TAI.

Effect of transition cow health and estrous expression detected by an automated activity monitoring system within 60 days in milk on reproductive performance of lactating Holstein cows

The objective of this observational study was to evaluate the association of transition cow health and estrous expression, detected by an automated activity monitoring system (Smarttag Neck, Nedap Livestock Management), with reproductive performance in lactating Holstein cows. A total of 3,750 lactating Holstein cows (1,563 primiparous cows and 2,187 multiparous cows) from a commercial dairy farm in Slovakia calving from January 2020 until July 2021 were enrolled on an ongoing basis. Activity data were recorded from d 7 until d 60 postpartum. Within this observational period, cows were classified into 3 categories: (1) no estrus event (Estrus0), (2) 1 estrus event (Estrus1), or (3) 2 or more estrus events (Estrus2+). Transition cow health was assessed by farm personnel within the first 30 d in milk (DIM) using standard operating procedures. Generalized linear mixed models were used to analyze continuous and categorical data. Cox proportional hazard models were used for time to event data. The overall prevalence of anestrus was 20.8%. Multiparous cows had a greater risk for anestrus compared with primiparous cows [odds ratio (OR) = 1.4]. Cows with stillbirth (OR = 1.76), retained placenta (OR = 2.19), puerperal metritis (OR = 1.48), or subclinical ketosis (OR = 1.51) had a greater risk for anestrus. In addition, cows calving in summer (OR = 0.82), autumn (OR = 0.38), or winter (OR = 0.56) had a higher incidence of anestrus than cows calving in spring. Estrous expression from d 7 until d 60 postpartum was associated with estrous duration (DU) and estrous intensity at first artificial insemination (AI). Cows in Estrus0 had the shortest DU at first postpartum AI (9.4 ± 0.18 h) compared with cows in Estrus1 (10.5 ± 0.13 h) and Estrus2+ (11.4 ± 0.12 h). Cows in Estrus2+ had a longer DU at first postpartum AI compared with cows in Estrus1. For Estrus0, Estrus1, and Estrus2+ cows, pregnancy per AI at first service was 42.5%, 50.9%, and 55.4%, respectively. Estrous expression from d 7 until d 60 postpartum was associated with time to first AI and time to pregnancy. Compared with Estrus0 cows, Estrus1 [hazard ratio (HR) = 1.43] and Estrus2+ cows (HR = 1.62) had an increased hazard of being inseminated within 100 DIM. Compared with Estrus2+, Estrus1 cows had a reduced hazard of being inseminated within 100 DIM (HR = 0.89). Compared with Estrus0 cows, Estrus1 (HR = 1.24) and Estrus2+ cows (HR = 1.46) had an increased hazard of becoming pregnant within 200 DIM. Median DIM to pregnancy were 121, 96, and 92 for Estrus0, Estrus1, and Estrus2+ cows, respectively. In conclusion, cows with transition cow disorders (i.e., stillbirth, retained placenta, puerperal metritis, or subclinical ketosis) had a greater chance for anestrus compared with healthy cows. Cows in Estrus0 had reduced estrous expression at first AI and inferior reproductive performance compared with cows that displayed estrous activity from d 7 until d 60.

Anogenital distance is associated with postpartum estrous activity, intensity of estrous expression, ovulation, and progesterone concentrations in lactating Holstein cows.

The objectives of this retrospective observational study were to determine the associations of anogenital distance (AGD) with (a) postpartum estrous activity, (b) diameter of the preovulatory follicle, (c) intensity of estrous expression, (d) postestrus ovulation, (e) corpus luteum (CL) size, and (f) concentrations of progesterone at estrus and on d 7 after estrus. Lactating Holstein cows (n = 178; 55 primiparous, 123 multiparous) were enrolled into the study during the first postpartum week. All cows were continuously monitored by a pedometer-based automated activity monitoring (AAM) system for estrus. Postpartum estrous activity was assessed using the AAM estrus alerts, in which cows with at least one true estrus alert (i.e., a relative increase in steps from each cow's baseline detected by the AAM and the presence of at least one follicle >15 mm, a CL <20 mm, or no CL detected by ultrasound) by the first 50 d in milk (DIM) were considered to have commenced estrous activity. At the estrus alert >60 DIM, ovulation was determined by ultrasound at 24 h, 48 h, and 7 d after estrus, and blood samples were collected at estrus alert and on d 7 after estrus for progesterone analysis. The AGD was measured from the center of the anus to the base of the clitoris and classified as either short- or long-AGD using 2 cut-points of 148 mm (predictive of the probability of pregnancy to first insemination; short-AGD, n = 115; long-AGD, n = 63) and 142 mm (the median AGD; short-AGD, n = 90; long-AGD, n = 88). Regardless of the cut-point used, early postpartum estrous activity by 50 DIM (67 vs. 54%), duration of estrus (11.6 vs. 9.7 h), and preovulatory follicle diameter (20 vs. 19 mm) were greater in short-AGD than in long-AGD cows. Increased peak of activity at estrus in short-AGD cows (354 vs. 258% mean relative increase) was affected by an interaction between AGD and parity in which multiparous long-AGD cows had lesser relative increase in activity than primiparous cows (217 vs. 386%, respectively). Mean progesterone concentration at estrus was lesser in short-AGD (0.47 vs. 0.61 ng/mL) than in long-AGD cows. The ovulatory response at 24 h did not differ, but at 48 h (91 vs. 78%) and on d 7 after estrus (97 vs. 84%) it was greater in short-AGD cows. Although CL diameter on d 7 after estrus did not differ, short-AGD cows had greater progesterone concentration 7 d after estrus than long-AGD cows (4.1 vs. 3.2 ng/mL, respectively). In conclusion, greater proportions of short-AGD cows commenced estrous activity by 50 DIM, had larger preovulatory follicles, exhibited greater duration of estrus, had reduced progesterone concentration at estrus, had greater ovulation rates and progesterone concentration 7 d after estrus compared with long-AGD cows, with no difference in CL size between AGD groups. Because all the differences in physiological characteristics of short-AGD cows reported herein favor improved reproductive outcomes, we infer that these are factors contributing to improved fertility reported in short-AGD cows compared with long-AGD cows.

PSXIII-B-9 Effects of Hemp (Cannabis Sativa) Supplementation on Behavior, Heart Rate, Hemogram and Serum Biochemistry Profiles of Beef cow-Calf Pairs During Weaning

Abstract Weaning is a stressful event that affects animal welfare and performance. This study examined the effects of industrial hemp (Cannabis sativa) supplementation on behavior, chute score and physiological responses of cow-calf pairs during weaning. Ten apparently healthy Angus cow-calf pairs, average BCS of 6.0, were randomly allocated to one of two groups for 7 days: Control (CON, 200g/head of commercial grower feed, n=10) and Hemp (HMP, 200g/head containing 80% commercial grower feed containing 20% hemp, n=10), daily. Hay and water were provided ad libitum. Chute and exit scores were recorded and blood samples were collected at d 0, 4 and 7 of the feeding period. Animal activity data was recorded using automated activity monitoring systems Moomonitor and IceQubes for cows and calves, respectively. At weaning, cow-calf pairs were separated abruptly and observed. Data was analyzed using Stata 14.2. Overall, rectal temperature, respiratory rate, rumination duration, rumen fluid pH and activity did not differ (P &amp;gt; 0.05) between treatments. Specifically, hemogram and serum biochemistry results did not differ (P &amp;gt; 0.05) between cow groups. However, resting duration tended to be greater in HEMP compared with CON (383.94±19.3 vs 298.60±16.1 mins/day, P = 0.06) cows. In addition, feeding duration was greater in HEMP compared with CON (473.8±24.5 vs 262.3±31.6 min/day) cows. In calves, heart rate was lower in HEMP compared with CON (62.67 vs 94.7 beats/min, P = 0.03). Hemoglobin concentration was smaller in HEMP compared with CON (12.6 vs 14.1mg/mL, P = 0.02). However, mean corpuscular hemoglobin concentration was greater in HEMP compared with CON (33.04 vs 32.04g/dl, P = 0.04). We concluded that hemp supplementation increased resting and feeding duration of cows, and reduced heart rate of calves during weaning. This is the first report on the use of hemp to improve welfare of cow-calf pairs during weaning.

Activity and rumination changes as predictors of calving in primiparous and multiparous Holstein cows

The objective of this study was to investigate if rumination and activity changes determined by an automated activity monitoring system (AAM) could be use as predictors of calving in Holstein cattle. A total of 94 Holstein cows (67 primiparous and 27 multiparous) were enroled in the study. Approximately 21 d before their expected calving date cows were moved into the pre-partum pen and fitted with a collar-mounted AAM (Heatime®, SCR Engineers). Rumination and activity behaviour were monitored continuously by the AAM and recorded every 2 h. Cameras were used to record calving time. Rumination and activity data from 100 h prior to calving to 6 h after calving were analysed using the PROC MIXED procedure in SAS. Mean rumination did not differ between parities, but primiparous cows had higher activity than multiparous cows during the entire study (P = 0.0002, 37.3 ± 0.5 vs. 33.4 ± 0.8 arbitrary units). Rumination began to decline steadily from -10 h in both parity groups and nadir was reached at 0 h and -2 h in primiparous and multiparous cows, respectively. The rumination arbitrary units and % changes between -10 h and nadir were 26.7 and 64.2% (P < 0.001) and 30.6 and 80.5% (P < 0.0001) for primiparous and multiparous cows, respectively. Activity started to increase steadily from -8 h in both parity groups, the highest activity change was reached at 0 h and -2 h in primiparous and multiparous cows, respectively. The activity arbitrary units and % changes between -8 h and the highest measure were 10.0 and 26.4% (P < 0.0001) and 6.6 and 20.0% (P = 0.0002) for primiparous and multiparous cows, respectively. In summary, both rumination and activity changes as measured by a collar-mounted AAM could be used as indicators for calving, with considerations made for the association of parity with both the degree and timing of behaviour change relative to calving.

Activity Monitoring for Toxicity Detection and Management in Patients Undergoing Chemoradiation for Gastrointestinal Malignancies.

Physical activity is associated with decreased hospitalization during cancer treatment. We hypothesize that activity data can help identify and triage high-risk patients with GI cancer undergoing concurrent chemoradiation. This prospective study randomly assigned patients to activity monitoring versus observation. In the intervention arm, a 20% decrease in daily steps or 20% increase in heart rate triggered triage visits to provide supportive care, medication changes, and escalation of care. In the observation group, activity data were recorded but not monitored. The primary objective was to show a 20% increase in triage visits in the intervention group. Secondary objectives were estimating the rates of emergency department (ED) visits and hospitalizations. Crude and adjusted odds ratios were computed using logistic regression modeling. There were 22 patients in the intervention and 18 in the observation group. Baseline patient and treatment characteristics were similar. The primary objective was met, with 3.4 more triage visits in the intervention group than in the observation group (95% CI, 2.10 to 5.50; P < .0001). Twenty-six (65.0%) patients required at least one triage visit, with a higher rate in the intervention arm compared with that in the observation arm (86.4% v 38.9%; odds ratio, 9.95; 95% CI, 2.13 to 46.56; P = .004). There was no statistically significant difference in ED visit (9.1% v 22.2%; P = .38) or hospitalization (4.5% v 16.7%; P = .31). It is feasible to use activity data to trigger triage visits for symptom management. Further studies are investigating whether automated activity monitoring can assist with early outpatient management to decrease ED visits and hospitalizations.

Effect of gonadotropin-releasing hormone administered at the time of artificial insemination for cows detected in estrus by conventional estrus detection or an automated activity-monitoring system

The objectives of this study were to determine the effects of GnRH at the time of artificial insemination (AI) on ovulation, progesterone 7 d post-AI, and pregnancy in cows detected in estrus using traditional methods (tail chalk removal and mount acceptance visualization) or an automated activity-monitoring (AAM) system. We hypothesized that administration of GnRH at the time of AI would increase ovulation rate, plasma progesterone post-AI, and pregnancy per AI (P/AI) in cows detected in estrus. In experiment 1, Holstein cows (n = 398) were blocked by parity and randomly assigned to receive an injection of GnRH at the time of estrus detection/AI (GnRH, n = 197) or to remain untreated (control, n = 201) on 4 farms. The GnRH was administered as 100 µg of gonadorelin acetate. Ovarian structures and plasma progesterone were assessed in a subset of cows (GnRH, n = 52; control, n = 55) in experiment 1 at the time of AI and 7 d later. In experiment 2, a group of 409 cows in an AAM farm were enrolled as described for experiment 1 (GnRH, n = 207; control, n = 202). Data were categorized for parity (primiparous vs. multiparous), season (cool vs. warm), number of services (first vs. > first), DIM (>150 DIM vs. ≤150 DIM), and for AAM cows in experiment 2 for activity level (high: 90-100 index vs. low: 35-89 index). Pregnancy diagnosis was performed between 32 and 45 d post-AI (P1) and 60 to 115 d post-AI (P2). In experiment 1, there was no difference in plasma progesterone at day of estrus detection (control = 0.09 ng/mL vs. GnRH = 0.16 ng/mL), 7 d later (control = 2.03 ng/mL vs. GnRH = 2.18 ng/mL), and ovulation rate (GnRH = 83.2% vs. control = 77.9%) between treatments. There were no effects of GnRH in experiment 1 for P/AI at P1 (control = 43.3% vs. GnRH = 38.6%), P2 (control = 38.4% vs. GnRH = 34.5%), and for pregnancy loss (control = 9.8% vs. GnRH = 8.2%). In experiment 2, there were no effects of GnRH for P/AI at P1 (control = 39.6% vs. GnRH = 40.1%), P2 (control = 35.0% vs. GnRH = 37.4%), and for pregnancy loss (control = 9.5% vs. GnRH = 6.2%). There was a tendency for a parity effect on P/AI for P1, but not P2 or for pregnancy loss. High-activity cows had greater P/AI in P1 (low activity = 27.9% vs. high activity = 44.1%), P2 (low activity = 21.8% vs. high activity = 41.2%), and lower pregnancy loss (low activity = 20.7% vs. high activity = 5.1%), but there were no interactions between treatment and activity level. The current study did not support the use of GnRH at estrus detection to improve ovulatory response, progesterone 1 wk post-AI, and P/AI. More research is needed to investigate the relationship between GnRH at the time of AI and activity level in herds using AAM systems.

Occurrence and greater intensity of estrus in recipient lactating dairy cows improve pregnancy per embryo transfer

The aim of this study was to determine the association between occurrence and intensity of estrous expression with pregnancy success in recipient lactating dairy cows subjected to embryo transfer (ET). Two observational studies were conducted. Holstein cows were synchronized using the same timed ET protocol, based on estradiol and progesterone in both experiments. At 9 d after the end of the timed ET protocol only animals that had ovulated were implanted with a 7-d embryo [experiment 1 (Exp. 1); n = 1,401 ET events from 1,045 cows, and experiment 2 (Exp. 2); n = 1,147 ET events from 657 cows]. Embryos were produced in vivo (Exp. 1 and Exp. 2) and in vitro (only Exp. 2), then transferred to recipient cows as fresh or frozen-thawed. Pregnancy was confirmed at 29 and 58 d after the end of timed ET protocol. In Exp. 1, animals had their estrous expression monitored through a tail chalk applied on the tail head of the cows and evaluated daily for chalk removal (no estrus: 100% of chalk remaining; estrus: <50% of chalk remaining). In Exp. 2, cows were continuously monitored by a leg-mounted automated activity monitor. Estrous expression was quantified using the relative increase in physical activity at estrus in relation to the days before estrus. Estrous expression was classified as no estrus [<100% relative increase in activity (RI)], weak intensity (100-299% RI), and strong intensity (≥300% RI). Data were analyzed by analysis of variance using mixed linear regression models (GLIMMIX) in SAS (SAS Institute Inc.). A total of 65.2% (914/1,401) and 89.2% (1,019/1,142) of cows from Exp. 1 and Exp. 2, respectively, displayed estrus at the end of the ovulation synchronization protocol. In Exp. 1, cows expressing estrus before to ET had greater pregnancy per ET than those that did not [41.0 ± 2.3% (381/914) vs. 31.5 ± 2.9% (151/487), respectively]. Similarly, in Exp. 2, cows classified in the strong intensity group had greater pregnancy per ET compared with cows in the weak intensity and no estrus groups [41.3 ± 2.2% (213/571) vs. 32.7 ± 2.7% (115/353) vs. 11.3 ± 3.5% (26/218), respectively]. There was no effect of ET type on pregnancy per ET in Exp. 1. However, in Exp. 2, cows that received an in vivo-produced embryo, either fresh or frozen, had greater pregnancy per ET compared with cows that received in vitro-produced embryo. Cows receiving embryos in the early blastocyst and blastocyst stage had greater fertility compared with cows receiving embryos in the morula stage. There was an interaction between the occurrence of estrus and the stage of embryo development on pregnancy per ET, cows which displayed estrus and received a morula or early blastocyst had greater pregnancy per ET than cows that did not display estrus. In conclusion, the occurrence and the intensity of estrous expression improved pregnancy per ET in recipient lactating dairy cows and thus could be used as a tool to assist in the decision making of reproduction strategies in dairy farms.

Economic comparison of an ear tag automated activity monitor for estrus detection with timed-AI in Holstein heifers

The objective of this study was to compare the economic performance of an ear tag automated activity monitor system (AAM) versus a timed-AI (TAI) protocol in Holstein heifers. In total, 340 heifers were enrolled onto the study at 13.5 mo of age and randomly assigned to receive either an AAM (n = 170) or TAI (n = 170) protocol before breeding eligibility (D 0). Heifers in the AAM group were fitted with an ear tag AAM and bred based on high activity alert from the system. Heifers in the TAI group received a progesterone releasing intravaginal device on D −8, followed by device removal and prostaglandin on D −3 and gonadotropin-releasing hormone with TAI on D 0. In both treatments, the majority of heifers received sex-sorted semen for the first AI and conventional semen for subsequent AIs, with three opportunities to become pregnant. All heifers were diagnosed for pregnancy approximately 25 d post AI using transrectal ultrasonography, with confirmation at 30 and 45 d. Non-pregnant heifers in the TAI group, were resynchronized using the same TAI protocol. A partial budget was used to compare the costs and benefits of switching from a TAI to an AAM protocol in heifers, including protocol, labour, and rearing costs for each treatment, as well as estimated calf and milk value. Sensitivity analyses were also conducted to determine the effect of pregnancy per AI (P/AI), outsourcing AI, AAM tag cost and herd size on the net outcome. There was no difference in overall P/AI or days to pregnancy between treatments. However, number of AI was greater in the TAI than the AAM group. For the first AI, the P/AI was less in the TAI compared to the AAM group; however, the interval to first AI was less in TAI. There was minimal difference in performance for the second and third AI. There was a net gain of $11.97 per heifer when switching from a TAI to AAM protocol, due to the increased P/AI to the first AI and reduced cost of hormones. Several variables in the sensitivity analyses affected the net outcome. Considering only the first AI, switching to an AAM collar and a larger herd size all increased the net gain. Considering a greater P/AI to the first AI in the TAI group, outsourcing AI, using more AAM ear tags, and smaller herd sizes resulted in a net loss when switching from TAI to AAM. The AAM system resulted in exceptional P/AI and may be an economically viable alternative to improve heifer reproductive efficiency in herds with suboptimal P/AI to TAI.