RESUMEN
Cow-calf contact (CCC) systems, although beneficial in many respects, introduce additional challenges to collect reliable data on milk production, which is important to assess individual cow efficiency and dairy farm profitability. Apart from weighing calves before and after each feeding, the amount of saleable milk lost due to calf suckling is practically impossible to measure. Here, we assess 2 indirect methods for estimating loss of saleable milk when housing cows and calves together in a robotic milking unit. In our study, treatment (CCC) cows and calves were kept together full time until the calves were 127 ± 6.6 d old (mean ± SD). Control cows were separated from their calves within 12 h of birth and then kept in the same unit as the treatment cows but with no access to either their own or treatment calves. Milk yield recording of both groups was performed from calving until pasture release at 233 ± 20 d in milk. The first estimation method relied on observed postseparation milk yield data, which were fed into a modified Wilmink regression model to determine the best-fitting lactation curve for the preseparation period. The second method was based on the cows' daily energy intake postseparation, calculated by measuring the daily feed intake and analyzing the energy content of the ration. The calculated energy intake was used to determine the average ratio between energy intake and the observed milk yield the following day for each individual cow, assuming constant rates of mobilization and deposition of body fat. The obtained ratio was then used to calculate the expected daily milk yield based on daily energy intake data during the preseparation period. In this paper, we analyzed data from 17 CCC cows kept together with their calves and 16 control cows; both groups calved from September to October 2020 and were followed up until release to pasture in May 2021. Saleable milk yield was lower in CCC cows than in control cows, both before and after separation. The 2 methods were used on data for control cows and showed milk yield loss using the lactation curve method (average of -3.4 ± 2.8 kg/d) and almost no loss using energy intake data (average of -1.4 ± 2.7 kg/d). Milk yield loss for CCC cows was estimated at average 11.3 ± 4.8 and 7.3 ± 6.6 kg milk/d, respectively. The proposed lactation curve estimation method tends to overestimate milk yield loss, whereas the method based on energy intake is more accurate. However, collecting detailed energy intake data per individual cow requires additional effort and equipment, which is not always feasible on commercial farms. Further research is needed to improve milk loss estimation and to better understand trade-offs in CCC systems.
Asunto(s)
Lactancia , Leche , Femenino , Bovinos , Animales , Leche/metabolismo , Ingestión de Energía , Ingestión de Alimentos , Granjas , Industria Lechera/métodosRESUMEN
Bovine digital dermatitis (BDD) is a contagious foot disease with worldwide occurrence in dairy cattle. The disease causes lameness and reduced animal welfare as well as economic losses for the farmer. The aetiology is not fully established but associations have been made with Treponema spp. Today, BDD diagnosis is mainly based on visual inspection of cattle feet, therefore this study aimed to develop a multiplex quantitative PCR (qPCR) assay targeting Treponema phagedenis, Treponema pedis, Treponema medium, and 'Treponema vincentii' to aid in diagnosis. The assay was tested for specificity on 53 bacterial strains and in silico on 168 Treponema spp. genomes, representative of at least 24 species. In addition, 37 BDD biopsies were analysed and the results compared to another qPCR assay published during the study period, which we modified by combining into a multiplex qPCR. The qPCR developed herein had a detection limit of 10 copies of each target species per PCR reaction. Both qPCR assays showed 100% specificity when tested on bacterial strains, but the qPCR developed in this study detected 3.4% more T. phagedenis-positive biopsies of lesion category M1-M4.1 than the modified assay. To conclude, the developed qPCR assay detecting T. phagedenis, T. pedis, T. medium, and 'T. vincentii' has high analytical sensitivity and specificity and provides a useful complementary tool for diagnosis and epidemiological studies of BDD. The assay could possibly also be used for contagious ovine digital dermatitis (CODD) as similar bacteriological profiles have been suggested for BDD and CODD, especially regarding certain Treponema spp.
Asunto(s)
Enfermedades de los Bovinos , Dermatitis Digital , Ovinos , Animales , Bovinos , Dermatitis Digital/diagnóstico , Dermatitis Digital/epidemiología , Dermatitis Digital/microbiología , Treponema/genética , Reacción en Cadena de la Polimerasa/veterinaria , Enfermedades de los Bovinos/epidemiologíaRESUMEN
Studies performed on individual research farms have reported that dairy cattle developing sole hemorrhages or sole ulcers in peak to mid lactation spent more time standing during the weeks around calving. The aim of this prospective observational longitudinal study was to evaluate whether this relationship is evident in commercial dairy herds. A convenience sample of 8 herds were visited every other week, and animals without previous severe horn lesions and deemed sound at 4 to 8 wk before calving were enrolled. Standing behavior was measured with data loggers attached to a rear leg, and standing time and duration of the longest standing bout were determined for each cow. Standing behavior was summarized into 3 periods: before (d -14 to -2), around (d -1 to 1), and after (d 2 to 14) calving. Average daily standing time and average daily longest standing bout were determined for each cow and period. Average daily standing time was normally distributed, with a mean ± standard deviation of 12.1 ± 1.6, 14.4 ± 2.2, and 13.8 ± 1.7 h/d for the 3 periods, respectively. Average daily longest standing bout was right skewed with a median of 3.6 h/d [interquartile range (IQR): 3.0 to 4.3; range: 1.7 to 12.1], 3.9 h/d (IQR: 3.1 to 4.8; range: 1.3 to 11.5), and 3.7 (IQR: 3.2 to 4.4; range: 1.5 to 11.7) h/d before, around, and after calving, respectively. Hoof trimming was performed 8 to 12 wk postpartum; hoof lesion data were summarized per cow, and the most serious injury of each type of lesion was noted. Sole hemorrhages or sole ulcers were found in 25 of 256 cows. Mixed-effect logistic regression models with herd as random effect were used to analyze the risk of developing sole hemorrhages and sole ulcers, using animals without hoof lesions as reference category. Separate models were fitted for the 2 standing behaviors, and for the periods before, around, and after calving. Change in standing behavior from before to after calving was also analyzed. Body condition score at calving, body condition score loss in early lactation, milk yield, parity, and days in milk at trimming were included as covariates. In this study, no evidence for an association was found between sole hemorrhages and sole ulcers and standing behavior before or around calving. Longer standing time and longer standing bouts after calving were associated with increased odds of developing sole hemorrhages and sole ulcers, as was an increase in standing bout duration from before to after calving. Animals with sole horn or white line lesions had higher unconditional sample odds of becoming lame (odds ratio = 2.5) and severely lame (odds ratio = 11.7) after calving, compared with animals with no registered lesions at trimming. Multiparous animals had higher lameness incidence, both before and after calving. Avoiding practices that exacerbate increases in standing time and standing bout duration in early lactation may reduce the incidence of sole hemorrhages and sole ulcers.
Asunto(s)
Enfermedades de los Bovinos , Pezuñas y Garras , Animales , Bovinos , Femenino , Lactancia , Cojera Animal , Estudios Longitudinales , EmbarazoRESUMEN
The primary aim of this prospective experimental study was to evaluate how the social environment after calving influenced standing behavior in primiparous cows. At calving, primiparous cows were mixed with familiar peers in a low-stocked pen (≤33% stocking density; n = 22) or mixed with unknown older cows at 100% stocking density (n = 20). All study cows were mixed with older cows 3 wk after calving. Time spent standing and perching (standing with only the front feet in the stall) were measured d 1 to 3 after calving using 5-min scan sampling. To evaluate if the low-stocked treatment constituted a low-stress social environment, agonistic interactions at the feed barrier were measured for 90 min following feed delivery for a subsample of cows in both treatments (12 cows/treatment). The daily behavioral time budget, including the 90 min following milking, was examined for this subset of cows. A secondary aim was to assess if the social environment after calving was related to the risk of developing claw horn lesions later in lactation. Sole and white line lesions were recorded at wk 6 and 12 after calving, and cows were categorized as either having or not having at least 1 hemorrhage of severity ≥3 (scale 1 to 5) for each lesion type and assessment. Prolonged standing after regrouping was not observed, and we found no differences in standing time and time spent perching between treatments. Agonistic behaviors directed toward the focal cows occurred less frequently in the low-stocked pen compared with the control. The number and severity of sole and white line lesions increased after calving. At wk 6 postpartum there was a numeric (but not statistically significant) difference between treatments in the proportion of primiparous cows that had white line hemorrhages of severity score ≥3 (low-stress social environment: 20% vs. control: 50%). In conclusion, under the conditions of this study the social environment did not influence standing behavior, but did affect agonistic interactions and may have influenced the risk of claw horn lesions in the weeks following calving. Further studies should evaluate the relationship between the social environment and claw health.
Asunto(s)
Conducta Animal , Enfermedades de los Bovinos/etiología , Enfermedades del Pie/veterinaria , Pezuñas y Garras , Medio Social , Animales , Bovinos , Enfermedades de los Bovinos/prevención & control , Enfermedades de los Bovinos/psicología , Femenino , Enfermedades del Pie/etiología , Enfermedades del Pie/prevención & control , Lactancia , Leche , Periodo Posparto , Estudios ProspectivosRESUMEN
In this longitudinal study, we tested the hypothesis that cows that are lame around dry-off are at increased risk of transition diseases (TD), including metritis, subclinical ketosis (SCK), retained fetal membranes, hypocalcemia, or displaced abomasum. We also hypothesized that the relationship between lameness and TD would be mediated through reduced feeding time. We enrolled 461 cows at 9 wk before their expected calving date on 6 commercial freestall farms in the lower Fraser Valley, British Columbia, Canada. Cows were gait-scored weekly using a scale of 1 to 5. Lameness status was classified based on consecutive gait scores as lame (2 consecutive gait scores = 3 or 1 score ≥4) or sound (2 consecutive gait scores ≤2). Lameness status was summarized as (1) lameness at dry-off (sound or lame); (2) lameness group (always sound = sound on all visits, chronically lame = lame on all visits, and other = changed from sound to lame or vice versa); and (3) proportion of weeks lame during the dry period. Body condition scores were recorded at dry-off and at calving and collectively used to calculate change in body condition for each cow. A subsample of cows (n = 159) was evaluated for feeding time once a week during the dry period. All cows were evaluated for SCK (positive = ß-hydroxybutyrate ≥1.2 mmol/L) and metritis (positive = foul smell, red/brown watery vaginal discharge) every 3 to 4 d between d 3 and 17 after calving. We retrieved data on treatment of retained fetal membranes, hypocalcemia, and displaced abomasum during the first 17 d after calving, cow parity, and milk production in the previous lactation from farm records. We created a binary variable, TD (any of SCK, metritis, retained fetal membranes, hypocalcemia, or displaced abomasum), to differentiate between healthy cows and cows that developed TD. Lameness at dry-off was associated with the occurrence of metritis and TD, but not with SCK. Cows that were chronically lame and cows that had an increased proportion of weeks lame during the dry period had higher occurrence of metritis and TD. Lameness was also associated with reduced feeding time, which in turn was associated with increased likelihood of SCK and TD, but not with metritis. Lameness was not associated with change in body condition; however, cows that lost body condition score during the dry period had increased odds of developing SCK, metritis, and TD. Change in body condition was highly associated with body condition score at dry-off. These results suggest that association between lameness and TD is partially mediated through reduced feeding time.
Asunto(s)
Enfermedades de los Bovinos/etiología , Conducta Alimentaria , Ácido 3-Hidroxibutírico/sangre , Animales , Colombia Británica , Bovinos , Enfermedades de los Bovinos/epidemiología , Industria Lechera , Granjas , Femenino , Marcha , Estado de Salud , Cetosis/etiología , Cetosis/veterinaria , Lactancia , Estudios Longitudinales , Paridad , Retención de la Placenta/veterinaria , Embarazo , Factores de RiesgoRESUMEN
The reliability of locomotion scoring is often low, making it unclear how a single gait score should be interpreted. In addition, differences in assessment frequency between longitudinal studies makes it hard to compare results. Our aims were to evaluate how lameness definition and assessment frequency affect measures of lameness incidence. Six dairy farms in British Columbia, Canada, were enrolled, and 262 cows that were sound at dry-off had their locomotion score (LS) assessed weekly from dry-off to calving, using a 1 to 5 scale. Cows were categorized as remaining sound or becoming lame using 3 different case definitions (LAME1: ≥LS3 at least once; LAME2: ≥2 consecutive scores of LS3, or ≥LS4 at least once; and LAME3: ≥3 consecutive scores of LS3, or ≥LS4 at least once). We analyzed the correspondence between the 3 definitions with percent agreement and weighted κ (linear and quadratic weighting). Comparing LAME1 to LAME3 resulted in lower percent agreement (53%) and κ values (linear κw = 0.50; quadratic κw = 0.64) than comparing LAME2 and LAME3 (85%; linear κw = 0.83; quadratic κw = 0.89), indicating that cows scored LS3 twice were likely to be scored LS3 a third time. We also compared the 3 case definitions against trim records from trimmings occurring 90 d or less before calving (n = 117), and used logistic regression models to determine sensitivity, specificity, and positive and negative predictive value. Using the LAME1 criterion resulted in high sensitivity (horn lesions = 0.90; infectious lesions = 0.92) and low specificity (horn = 0.21; infectious = 0.24). We observed higher specificity for LAME2 (horn = 0.62; infectious = 0.66) and LAME3 (horn = 0.71; infectious = 0.77), but LAME2 had higher sensitivity than LAME3 (horn = 0.89 vs. 0.64; infectious = 0.69 vs. 0.64). When evaluating the effects of assessment frequency, we obtained 3 data sets by keeping every, every other, and every third locomotion assessment, and using LAME2 as a case definition. More cows were categorized as lame when assessment frequency increased. Of the cows that were classified as lame when assessed weekly, 72% of the mildly lame, and 33% of the severely lame were classified as sound when assessed every third week. Our results suggest that a single LS3 score should not be used as a criterion for lameness in longitudinal studies. To correctly identify new cases of lameness, dairy cows should be assessed at least every 2 wk.
Asunto(s)
Enfermedades de los Bovinos/epidemiología , Cojera Animal/epidemiología , Animales , Colombia Británica , Bovinos , Enfermedades de los Bovinos/clasificación , Enfermedades de los Bovinos/diagnóstico , Femenino , Marcha , Incidencia , Cojera Animal/clasificación , Cojera Animal/diagnóstico , Modelos Logísticos , Reproducibilidad de los ResultadosRESUMEN
Lameness has been extensively studied in lactating cows, whereas few studies have reported on lameness during the dry period. We conducted a prospective longitudinal study to describe the epidemiology of lameness during the dry period and to identify risk factors associated with onset, cure, and chronic cases of lameness. A total of 455 cows from 6 freestall commercial dairy farms were enrolled at 9 wk before calving and gait scored weekly until calving using a 5-point scale. A subset of cows was also followed fortnightly after calving to measure the association between lameness during the dry period and lameness during early lactation. Body condition score (BCS) was assessed in a 5-point scale using increments of 0.5. Hoof-trimming records, parity, and previous lactation milk production were retrieved from farm's database. Cows were considered sound when 2 consecutive scores were ≤2 and lame when 2 consecutive scores = 3, or any assessment with score >3; when in a sequence of scores only one score = 3 (or ≤2), the cow was considered sound (or alternatively lame). Following this lameness definition, we derived weekly lameness status for each cow and calculated the number of new cases of lameness, the number of cure cases and the number of chronic cases. The incidence rate of lameness cases during the dry period was 8.2 lameness cases/100 cow per wk, whereas cure rate was 7.1 cure cases/100 cow per wk; at the end of the dry period 50% of cows had developed lameness and 36% were cured. Multilevel logistic regression models using farm as random effect were fitted to assess (1) the association between being lame in wk 2 or 8 postcalving with being lame in the last week precalving, (2) risk factors for lameness onset, (3) risk factors for lameness cure, and (4) risk factors for chronic lameness. Cows that were lame in the week immediately before calving were more likely to be lame in wk 2 and 8 after calving. We found that the interaction between parity and hoof-trimming before dry-off was associated with lameness onset; primiparous cows that were trimmed before dry-off had lower odds of developing lameness, whereas the opposite was found for multiparous cows. The same interaction was also associated with the odds of chronic lameness. Cows that were diagnosed with noninfectious hoof lesions compared with cows that were not diagnosed with hoof lesions before dry-off, and cows that had BCS <3 compared with cows with BCS 3.0 to 3.5 at dry-off had higher odds of chronic lameness. Conversely, primiparous cows and cows with BCS 3.0 to 3.5 had higher odds of curing lameness during the dry period. Our results suggest that the dry period may be a period of high risk for lameness development and that hoof-trimming before dry-off may not be effective for all cows.