The objectives of the present study were to evaluate the effect of per rectal amniotic sac palpation (ASP) for pregnancy diagnosis during the late embryonic period on pregnancy loss, calving rates, and abnormalities in newborn calves. A controlled, randomized, blocked, blind experiment containing 680 lactating pregnant dairy cows with a viable embryo diagnosed by transrectal ultrasonography was performed. Two dairy operation sites (farm A and farm B) were selected. At each farm, the cows were randomly divided into control (CON) and ASP groups. The CON group was not subjected to pregnancy diagnosis via per rectum palpation. The ASP examinations were performed by one experienced veterinarian between Days 34 and 45 after breeding. All cows were reevaluated by transrectal ultrasonography only between 2 and 4 weeks later. Two calving rates were calculated: calving rate 1 (cows that calved from the initial number of pregnant cows) and calving rate 2 (cows that calved from cows pregnant at reexamination). In farm A, the percentages of early pregnancy loss were 11.5% (19 of 165) and 13.2% (24 of 182) for the CON and the ASP groups, respectively (P = 0.64). In farm B, the percentage of early pregnancy loss was 11.2% (19 of 170) for the CON group and 8.8% (14 of 159; P = 0.48) for the ASP group. In farm A, the percentage of late pregnancy loss was 7.6% (11 of 145) for the CON group and 5.5% (8 of 155; P = 0.39) for the ASP group. In farm B, the percentage of late pregnancy loss was 3.7% (5 of 137) for the CON group and 6.3% (8 of 127; P = 0.32) for the ASP group. In farm A, early pregnancy loss was higher than late pregnancy loss (12.4% vs. 6.3%; P = 0.01), and in farm B, the same tendency was detected (10.0% vs. 4.9%, for early and late pregnancy loss, respectively; P = 0.02). In farm A, calving rate 1 was 81.2% (134 of 165) for the CON group and 80.8% (147 of 182; P = 0.92) for the ASP group. Calving rate 2 for the same groups was 92.4% (134 of 145) and 94.8% (147 of 155), respectively (P = 0.68). In farm B, calving rate 1 was 77.7% (132 of 170) for the CON group and 74.8% (119 of 159; P = 0.55) for the ASP group. Calving rates 2 for the same groups were 87.4% (132 of 151) and 82.1% (119 of 145), respectively (P = 0.20). Two female calves with atresia coli were diagnosed only in the CON group. It was concluded that ASP during the late embryonic period for pregnancy diagnosis did not increase the pregnancy loss, affect calving rates, or produce abnormalities in calves.

Our objective was to evaluate the effect of season of calving, associated with variable levels of heat stress, on the dynamics of rumination during the prepartum period and early lactation of cows that were healthy or affected by peripartal health disorders. Three weeks before the estimated due date, 210 multiparous Holstein cows at the University of Florida Dairy Unit were affixed with a neck collar containing rumination loggers, providing rumination time (RT) in 2-h periods. One blood sample was collected in a subpopulation of cows (n=76) at 12 to 48h postcalving to assess metabolic status by determining serum calcium, nonesterified fatty acid, and β-hydroxybutyrate concentrations. The occurrence of peripartal health disorders (dystocia, clinical ketosis, clinical hypocalcemia, metritis, and mastitis) was assessed by University of Florida veterinarians and trained farm personnel. We analyzed the dynamics of daily RT over ± 14d relative to parturition in cows that were healthy or affected by specific health disorders by season of calving [hot season, June to September (n=77); cool season, November to April (n=118)] using repeated measures analysis and comparison of least squares means at different time points relative to calving. Rumination was consistently reduced on the day of calving in both healthy and sick cows in both the hot and cool seasons. Only hot-season calvings had shorter average daily RT prepartum and postpartum in cows affected by severe negative energy balance and subclinical ketosis. Dystocia during the hot season was associated with shorter daily RT prepartum; for cool-season calvings, cows with dystocia had reduced RT postpartum. We also observed reduced RT in cows with ketosis prepartum and postpartum in both the hot and cool seasons. Daily RT was reduced postpartum in cows with hypocalcemia and mastitis that calved during the cool season, and it was shorter in cows with metritis in both the hot and cool seasons. Our results indicated that the effect of heat stress on changes in rumination patterns around calving for sick cows depends on the specific health disorder or metabolic condition.

Environmental influences during different stages of pregnancy can induce lifelong changes in the structure, physiology, and metabolism of the offspring. Our hypothesis was that season of conception (when the offspring was conceived), associated with heat stress conditions at conception and during the initial stages of embryonic development, affects the lifetime performance and survival of the female offspring after birth. The objective was to analyze the association between month of conception and subsequent survival, fertility, and milk yield in cows maintained on dairy farms in Florida, where the climate during the summer is hot and humid but winters are mild. Initial data consisted of 667,104 Dairy Herd Improvement lactation records from cows calving between 2000 and 2012 in 152 herds. Dates of conception were estimated as birth date minus 280 d. The magnitude of heat stress in each herd was quantified by comparing milk yield during summer and winter. Wood's lactation curves were fitted to adjust milk yields for effects of days in milk, and residuals were obtained for each calendar month. A sine function was fitted on the 12 residuals per farm. The difference between the highest and lowest points on the sine function was termed the seasonality index, a measure of the direct effect of heat stress on milk production. Herds were categorized in 3 levels of seasonality [low (seasonality index values less than the 25th percentile value; <2.84), medium (values within the interquartile range), and high (values greater than the 75th percentile value; >5.22)]. Cows were grouped by their month of conception: summer (July-September) and winter (December-February), and comparisons were performed by parity using logistic regression, ANOVA, and survival analysis. Two models were developed. Model A included the complete population of cows (n = 337,529 lactation records) conceived in winter or summer. Model B included cows (n = 228,257 lactation records) that had parent-average genetic information available to be able to correct for farmer's use of lower genetic merit of sires in summer. Other variables included in the models were month and year of calving, age at first calving, and herd. Models were run per parity group (1, 2, and ≥3). In both models, age at first calving was lower for cows conceived during winter versus summer. The odds (95% confidence interval) of survival to a second calving for cows conceived in winter were 1.21 and 1.15 times the odds of survival for cows conceived in summer for models A and B, respectively. Numbers of days from calving to first breeding and from calving to conception were consistently smaller for winter versus summer months of conception across all parity categories. Milk yields (305 d and by 70 d in milk) were greater for cows conceived in winter versus summer. In conclusion, cows that were conceived in the winter had better subsequent survival and performance than cows that were conceived in the summer. There is evidence that season of conception may have lifelong consequences for the...

The objective of this study was to characterize incidences of health disorders during early lactation in a large population of Holstein cows calving in 2 seasons across multiple US dairy herds. In addition, cumulative effects of combinations of health-related events on fertility and survival by season of calving and parity number were tested. Data were prospectively collected from a total of 11,729 cows in 16 herds located in 2 regions in the United States [north (7,820 cows in 10 herds) and south (3,909 cows in 6 herds)]. Cows were enrolled at parturition and monitored weekly for disease occurrence, reproductive events, and survival. Health-related events were grouped into reproductive disorders (REP; dystocia, twins, retained fetal membranes, metritis, and clinical endometritis) and other disorders (OTH; subclinical ketosis, mastitis, displaced abomasum, and pneumonia). Counts of health events within 50 d postpartum were added into each of the groups and categorized as 0, 1, 2, 3, and ≥4 for REP and 0, 1, 2, and ≥3 for OTH. Multivariable logistic regression was used for testing potential associations between categories of disease occurrence and outcome variables, including resumption of ovarian cyclicity, pregnancy per artificial insemination (AI), pregnancy loss, and survival up to and after 50 DIM. The incidence of disease varied with season of calving and parity, and these 2 variables were associated with the reproductive and survival outcomes. The size of the detrimental effect of disease incidence on reproduction and survival depended on disease group and varied for each specific outcome. Resumption of ovarian cyclicity decreased as incidences of disorders increased in both REP and OTH categories. Pregnancy at first AI also was smaller in greater number of REP categories, but the effect of number of OTH categories on pregnancy at first AI was not consistent. Similarly, pregnancy loss at first AI was not affected consistently by REP or OTH. Survival was reduced by REP and OTH. The magnitude of these negative effects was variable, depending on season of calving and parity, but consistently increased with the number of health events during early lactation.

The objective was to evaluate the association between changes in daily rumination time (dRT) and early stages of disease during early lactation and to assess the performance of two proposed disease detection indices. This cohort study included 210 multiparous Holstein cows at the University of Florida Dairy Unit. Cows were affixed with a neck collar containing rumination loggers providing rumination time. The occurrence of health disorders (mastitis, metritis, clinical hypocalcemia, depression/dehydration/fever (DDF), digestive conditions, lameness and clinical ketosis) was assessed until 60 days in milk. Two indices were developed to explore the association between dRT and disease: (i) Cow index (CIx), based on changes in dRT in the affected cow during the days before the diagnosis of health disorders; (ii) Mates index (MIx), index based on deviations in dRT relative to previous days and healthy pen mate cohorts. Subsequently, an alert model was proposed for each index (ACIx and AMIx) considering the reference alert cut-off values as the differences between average index values in healthy and sick cows for each specific disease. The sensitivity (SE) of ACIx detecting disease ranged from 42% (digestive conditions and DDF) to 80% (clinical hypocalcemia) with 84% specificity (SP). The SE of AMIx ranged from 46% (digestive conditions and DDF) to 100% (clinical hypocalcemia) with 85% SP. Consistent reductions in rumination activity, both within cow and relative to healthy mate cohorts, were observed for each health disorder at the day of diagnosis. However, the ability of the proposed algorithms for detecting each specific disease was variable.

Body condition score (BCS) and disease records are commonly available in dairy operations. However, the effect of BCS changes (ΔBCS) considering specific health profiles has not been investigated extensively. The objective of this study was to assess the effects of different levels of ΔBCS on fertility, milk yield, and survival of Holstein cows diagnosed with reproductive disorders (REP; dystocia, twins, retained fetal membranes, metritis, and clinical endometritis), other health disorders (OTH; subclinical ketosis, left displaced abomasum, lameness, clinical mastitis, and respiratory disease), or with no disease events (HLT) within 40 days in milk (DIM). Data included lactation information from 11,733 cows calving between November 2012 and October 2014 in 16 herds across 4 geographical regions in the United States (Northeast, Midwest, Southwest, Southeast). Cows were evaluated for BCS at 5 ± 3 DIM (BCS5) and at 40 ± 3 DIM (BCS40) and the difference between BCS40 and BCS5 was classified as excessive loss of BCS (EL; ΔBCS ≤−0.75), moderate loss (ML; ΔBCS = −0.5 to −0.25), no change (NC; ΔBCS = 0), or gain of BCS (GN; ΔBCS ≥0.25). Multivariable logistic regression was used for assessing potential associations between the outcomes of interest and ΔBCS and health. The effect of the interaction term ΔBCS by health group was not statistically significant for any of the study outcomes. The odds of resumption of ovarian cyclicity (ROC), in GN, NC, and ML cows were 1.94 (95% CI: 1.57-2.40), 1.59 (1.28-1.97), and 1.27 (1.10-1.47) times greater than the odds of ROC in EL cows, respectively. The odds of pregnancy at 150 DIM (P150) in GN cows were 1.61 (1.20-2.17) times greater than the odds of P150 in EL cows. Cows with REP or OTH disorders had smaller odds of ROC compared with HLT cows [REP: OR = 0.65 (0.56-0.76) and OTH: OR = 0.79 (0.68-0.92)]. For pregnancy outcomes, REP cows had smaller odds of pregnancy at the first artificial insemination compared with HLT cows [0.70 (0.58-0.84)]. Similarly, REP cows had smaller odds of being diagnosed pregnant by 150 and 305 DIM compared with HLT cows [P150: 0.73 (0.59-0.87), P305: 0.58 (0.49-0.69)]. Overall, average daily milk within the first 90 DIM was greater in EL (39.5 ± 1.13 kg/d) and ML (38.9 ± 1.11 kg/dl) cows than in NC (37.8 ± 1.12 kg/d) and GN (36.2 ± 1.12 kg/d) cows. On the other hand, average daily milk within the first 90 DIM was lower in REP (37.0 ± 1.11 kg/d) cows compared with OTH (38.7 ± 1.12 kg/d) and HLT cows (38.6 ± 1.11 kg/d). The magnitude of ΔBCS and the health status of early lactation cows should be considered when assessing subsequent cow performance and survival.

The objectives of the present investigation were to evaluate the pregnancy diagnosis by detection of either the allantochorion membrane (FMS) or amniotic sac (ASP) by per rectum palpation (PRP) during late embryonic or early fetal period on pregnancy loss (PRL) at reexamination, calving rates, and abnormalities in newborn calves. A controlled randomized blind design with 800 lactating dairy pregnant cows diagnosed by transrectal ultrasonography (TRUS) between Days 35 and 57 of gestation from one dairy farm were included. The cows were randomly divided according to detection of allantochorion membrane (FMS group; n = 264), detection of amniotic sac (ASP group; n = 266), and TRUS (control [CON] group; n = 270). TRUS was considered as the criterion standard method of comparison. The entire PRP was performed by one experienced veterinarian. Then, all the cows were reexamined only by TRUS between 2 and 4 weeks later by two independent veterinarians to assess PRL. The calving rate one (number of cows calved divided by the number of cows initially pregnant) and calving rate two (number of cows calved divided by the number of cows pregnant at reexamination) for each group was calculated. All abortions and stillborns were necropsied, and calves alive were followed for 5 days. The overall initial PRL (between initial pregnant cows and reexamination) for FMS, ASP, and CON groups was 7.4% (19/258), 8.8% (23/262), and 9.2% (24/260), respectively (P = 0.75). The overall late PRL (between reexamination and calving) for FMS, ASP, and CON groups was 4.2% (9/213), 5.7% (12/209), and 4.2% (9/216), respectively (P = 0.71). The calving rate one for FMS, ASP, and TRUS groups was 79.1% (204/258), 75.2% (197/262), and 79.6% (207/260), respectively (P = 0.63). The calving rate two for the same groups was 85.4% (204/239), 82.4% (197/239), and 87.7% (207/236), respectively (P = 0.27). The number of fetuses aborted late, premature, and mature dead from FMS, ASP, and CON groups was 6, 4, and 5, respectively (P = 0.85), and no abnormalities at necropsy were detected. One stillborn male calf with atresia coli after 281 days of gestation from a cow examined by ASP at Day 51 was diagnosed. It was concluded that the use of either FMS or ASP for pregnancy diagnosis during late embryonic or early fetal period did not increase the PRL, affect calving rates, or produce calves with congenital abnormalities.

AIMS To describe milk yield and culling risk in cows diagnosed with left displacement of abomasum (LDA) treated either conservatively, by right flank pyloric omentopexy, or rolling and toggling, compared with normal herdmates from four Chilean dairy herds. METHODS Historical records were obtained from four commercial dairy farms located in Central Chile for cows with a history of LDA between 2010 and 2012, and healthy herdmates. Cows with LDA were categorised into three groups: cows treated with right omentopexy (ST, n=58), cows treated by toggle suturing (TT, n=15) and cows treated conservatively (CT, n=56). Control cows (n=129) were selected from unaffected cows, matched by days in milk (DIM), parity and herd with affected cows. Groups were compared for risk of culling up to 300 DIM and for milk production up to 5 months of lactation using survival and Cox proportional hazard models and mixed models for repeated measures, respectively. RESULTS Compared with cows in the Control group, the risk of being culled up to 300 DIM was 9.1 (SE 0.62) times greater in ST cows, 10.4 (SE 0.68) times greater in TT cows, and 37.3 (SE 0.61) times greater in CT cows (p<0.01). In the first 5 months of lactation, compared with cows in the Control group, mean daily milk production was 23.3 (SE 1.5) kg less in ST cows, 15.3 (SE 1.6) kg less in TT cows, and 30.1 (SE 1.3) kg less in CT cows (p<0.001). CONCLUSIONS AND CLINICAL RELEVANCE Cows in four dairy herds in central Chile diagnosed and treated for LDA produced significantly less milk and had a higher risk of culling than healthy herdmates. Although cows treated surgically or with toggle suture never recovered to the extent of healthy cows, they produced more milk than cows treated conservatively. However, the retrospective nature of the data, the inclusion of only four herds and the non-random allocation to treatments means that these conclusions cannot be extrapolated to the overall dairy cattle population in Chile.