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Cow-calf systems represent a significant research area in animal husbandry, with differences depending on the final product (meat or milk). This study aimed to apply text mining and topic analysis on literature describing cow-calf systems in European, American, and Brazilian beef and dairy sectors between 1998 and 2023. Additionally, cow-calf contact (CCC) literature data was manually extracted. Our findings revealed the presence of 11 research areas among literature on cow-calf systems, with different priorities identified in the beef and dairy sectors. Beef industry mainly focused on animal proficiency and nutrition, while dairy on animal welfare and CCC, which showed a growing trend as emerging research topic, mostly in the EU. Current debates around calf welfare and EU's planned animal welfare legislation revision appeared to be driving the increasing interest in this topic. Studies in the beef sector were mainly localized in Brazil, showing that research in different contexts and species is important for CCC implementation. Manual data extraction showed considerable variation in the retained CCC documents regarding sample size, type of contact, methods and CCC duration. Learning about the varied CCC approaches used in beef and dairy farms in different locations, concentrating on their strengths and weaknesses, will help to develop novel solutions to global challenges. Adopting validated and robust indicators would help scientists and policymakers to monitor the system's quality. To improve CCC feasibility, match consumer demands, and move towards One Welfare and One Health, future research should focus on a variety of situations to overcome the current shortcomings.

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Internationally, consumer dissatisfaction with cow-calf separation at birth has led to increased interest in alternative calf-rearing methods, specifically cow-calf contact (CCC) systems. The objectives of this preliminary study were to estimate whether CCC could be incorporated into an Irish spring-calving, pasture-based system, and to investigate the effects on cow milk production and health. Three systems were compared: the conventional Irish system (CONV;18 cows), cow and calf were separated < 1 h postbirth, cows were pasture-based and milked twice-a-day; a full-time access system (FT;14 cows), cow and calf were allowed constant, unrestricted access, were pasture-based, and cows were milked twice-a-day; and a part-time access system (PT;18 cows), cow and calf had unrestricted access when indoors at night, cows grazed outdoors by day while calves remained indoors, and cows were milked once-a-day in the morning. Cows were blocked and balanced across the three systems by previous lactation machine milk yield (MMY), BW, and body condition score (BCS). Following an 8-week CCC period, all calves were weaned (FT and PT underwent a 7-d gradual weaning and separation process) and all cows were milked twice-a-day. Cow MMY was recorded daily and milk composition was recorded weekly; milk data were analysed from weeks 1 to 8 (CCC period), weeks 9 to 35 (post-CCC period), and weeks 1 to 35 (cumulative lactation). Cow BW and BCS were taken weekly for weeks 1-12, and at the end of the lactation. During the CCC period, all systems differed (P < 0.001) in MMY (mean ± SEM; 24.0, 13.6, and 10.3 ± 0.50 kg/d for CONV, FT, and PT cows, respectively). After the CCC period, CONV MMY (20.2 ± 0.48 kg/d) remained higher (P < 0.001) than the FT (16.6 kg/d) and PT cows (15.7 kg/d). The FT and PT cows yielded 24 and 31% less in cumulative lactation MMY and 26 and 35% less in cumulative lactation milk solids yield, respectively, compared to CONV (5 072 ± 97.0 kg and 450 ± 8.7 kg). During the CCC period, somatic cell score was higher (P = 0.030) in PT cows (5.15 ± 0.118) compared to FT cows (4.70 ± 0.118), while CONV (4.94 ± 0.118) were inconclusive to both. The PT cows (523 ± 4.9 and 520 ± 6.8 kg) were heavier than the CONV (474 ± 4.9 and 479 ± 6.8 kg) and FT (488 ± 4.9 and 487 ± 6.8 kg) cows at week 4 and week 8 (both P < 0.001). The PT cows had higher BCS than CONV and FT at all observed times. This preliminary research suggests that although CCC was incorporated without impacting cow health, the two CCC systems investigated negatively affected cow production.

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Cow-calf contact (CCC) rearing is becoming an increasingly popular alternative to the common practice of early separation of cow and calf in dairy management. Milkability can be impaired in nursing cows, which contributes to the loss of machine milk yield caused by calf intake, especially in pure dam-calf contact (DCC) systems. The aims of this study were (1) to describe the current status quo of DCC rearing regarding management and milking and (2) to evaluate the effects of DCC (suckling and milking vs. milking alone) and the effects of different types of DCC on milkability parameters, teat condition, and behavior during milking on Swiss DCC farms. By means of 17 telephone interviews with DCC farmers, we collected data on DCC management, housing, separation and weaning processes, milking procedures and techniques, and perceived milkability problems. Subsequently, we collected data on 10 of the interviewed DCC farms (183 cows): 4 DCC farms with a whole-day contact (WDC) system, 3 farms with DCC before milking (CBM), and 3 farms with DCC after milking (CAM). Five farms on which calves had no contact with dams were chosen as reference farms (178 cows). Using a milk flow meter, the occurrence of ejection disorders, bimodality of the milk flow curve, machine milk yield, duration of the decline phase, and duration of prestimulation were measured. The average mouthpiece chamber vacuum during the main milking phase and hind leg activity during milking were measured using a pressure sensor and an accelerometer, respectively. After cluster removal, the teat condition was evaluated, and a stripping milk sample was taken for fat content analysis. The interview results revealed that 8 of the 17 farms surveyed had a WDC system, and 2 farms operated a daytime DCC system. Contact before milking was applied by 3 farms, and 3 farms allowed CAM. On one farm, calves had access to dams 3 times a day. A great diversity in cow-calf management was found. In the on-farm data collection, 20 milkings of a total of 701 milkings examined met the criteria for a clear ejection disorder, with 17 of these observations occurring on WDC farms and none on reference farms. The stripping milk fat content was lower in nursing cows, indicating a lower degree of udder emptying. Machine milk yield was higher in nursing CAM cows than in nursing WDC and CBM cows. Farm types did not differ regarding teat condition, hind leg activity, or the occurrence of bimodal milk flow curves. In conclusion, the large variation in individual management approaches to DCC rearing even within DCC types, such as calf housing or cow breeds, implies caution when interpreting results. Contact after milking may be the system most beneficial for some productivity parameters, but adequate calf supply must be ensured. Higher amounts of milk remaining in the udder after cluster removal indicate that nursing can affect milkability, but future research should consider the effects of udder filling before milking to better interpret the fat content of stripping milk.

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Cow-calf contact has been suggested as an alternative to the common practice of early separation of dairy cow and calf. Increasing cow-calf contact poses challenges by reducing the machine milk yield and increasing separation stress. Part-time cow-calf contact may prove more feasible than full-time contact for farmers but may affect the maternal behavior of the cows. Gradually reducing the daily contact could gradually wean the calf off milk, preparing it for separation. This study aims to investigate (1) how cows' maternal behaviors toward their own calf are affected by part-time contact, and (2) whether calves' suckling behavior is reduced by reducing daily cow contact. Fifty-six dairy cows and their calves were assigned to either full-time (23 h/d) or part-time (10 h/d) cow-calf contact for 7 wk (main rearing period). This was followed by 2 wk of either reduced contact (50% in wk 8, then 25% of original contact time in wk 9) or unchanged contact. First, the maternal behavior of full- and part-time cows was observed for 24 h in the third week of the main rearing period. Part-time cows spent less time nursing and grooming their own calf than full-time cows did. However, the amount of nursing in the inverse parallel position and the probability of a cow nursing a calf other than her own did not differ between the 2 treatments. Second, calf suckling behavior was observed for 24 h in both weeks of the reduced contact period. Averaged across both observations, total suckling time (i.e., time spent suckling any cow) was lower in part-time calves that experienced reduced contact compared with part-time calves with unchanged contact. In wk 9, time spent suckling only the dam was lower for full-time calves with reduced contact compared with part-time calves with unchanged contact. In conclusion, although we found a lower nursing and grooming time in part-time cows compared with full-time, we found no difference between treatments with regard to nursing in the inverse parallel position and nursing a calf other than the cow's own. The effect of gradually reducing cow-calf contact on calves' suckling time requires more research.

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Cow-calf surveillance data provide critical information about changing herd demographics, productivity, health, and management as well as the opportunity to investigate the impact of differing management practices. A national cow-calf network was established to collect baseline information on herd health, production performance measures, and management. Questionnaires were used to collect information on herd attributes as well as data for the calving season, breeding, pregnancy testing, and weaning for herds from across Canada. From 2018 to 2022, a total of 565 calving record questionnaires, representing 110,658 calving female records from 171 herds were returned, along with 543 herd breeding to weaning questionnaires. Suggested benchmark values based on the 25th percentiles from Western and Eastern Canada were determined to be <5% for non-pregnancy, <2% for calf death from birth to 24 h, and < 2% for calf death from 24 h to weaning. Herds from Eastern Canada were more likely to report any assistance at calving (p < 0.001) than herds from Western Canada. Participating herds from the east had longer breeding (p < 0.001) and calving (p < 0.001) seasons than those from the west and were also more likely to use artificial insemination or embryo transfer (p < 0.001). Timing of calving season and use of large pastures for calving were not associated with mortality at birth. Herds that started calving before April were more likely to have calves die before 30 d than those that started calving later; however, this difference was not observed between 30 d and weaning. Herds that started to calve earlier were also more likely to report treating more calves for bovine respiratory disease, diarrhea, and navel or joint infections as well as to calf deaths from respiratory disease. Calves from herds in the east were more likely to be treated or die from diarrhea than from the west. Females from herds that started calving later were less likely to be pregnant. The unique longitudinal productivity and health data resulting from this network established a national baseline to address region-specific needs for knowledge translation and solutions to enhance productivity and support sustainability.

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In natural settings, newborn calves hide for several days before joining the herd. It is unclear whether dairy calves housed indoors would show similar hiding behaviour. This study aimed to describe the use of an artificial hide provided to calves during temporary separation from the dam and assess the effect it has on lying and sleep-like behaviour, as well as heart rate variability (HRV). Twenty-eight cow-calf pairs were randomly assigned to having a hide (n = 14), or no hide (n = 14). Hide use (n = 14), as well as lying and sleep-like behaviour (n = 28), were recorded continuously via video camera during the first hour after the dam was removed for morning milking on day three to seven. Heart rate and R-R intervals were recorded using Polar equine monitors for a subsample of 12 calves (n = 6 per treatment) on day six. Descriptive statistics were calculated for hide use. Wilcoxon Signed Rank tests were used to evaluate whether having a hide affected lying and sleep-like behaviours as well as HRV. Hide use decreased over days and was highly variable between calves. Lying behaviour did not differ between treatments. Duration of sleep-like behaviour was higher for calves without a hide compared to those with a hide. Calves with a hide tended to show signs of higher HRV and parasympathetic activity compared to calves without a hide. Results suggest that providing a hiding space to young calves may be beneficial during periods when the cow is removed from the pen for milking.

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The weaning and separation phase remains one of the biggest challenges for cow-calf contact systems, but a gradual process that better mimics the naturally occurring reduction in milk intake has not yet been scientifically investigated. Therefore, the aim of our study was to compare behavioral and physiological indicators of distress in 3-mo-old dam-reared dairy calves (with previous full-time cow-calf contact) weaned and separated either via gradual reduction of contact time with the dam (GR; 1 wk of half-day contact, 1 wk of morning contact, and 1 wk of fence-line contact before complete separation, n = 18) or via 2-step weaning using a nose flap (NF, 2 wk of access to the dam with a nose flap, 1 wk of fence-line contact before complete separation, n = 18). Behavior was recorded 1 wk before (or for lying 3 wk before) weaning start and during the 3 wk weaning and separation period with direct observations on 4 d/wk or via accelerometers (locomotor play, lying behavior). Blood and fecal samples were taken twice per week from weaning start until 3 wk after weaning start. Calves were weighed weekly. Statistical analysis was conducted using (generalized) linear mixed models. Over the whole weaning and separation phase, NF calves showed a stronger decrease in the number of lying bouts, amount of locomotor play, and ADG, as well as a higher increase in TMR feeding time compared with GR calves, whereas GR calves vocalized more often and showed more searching behavior than NF calves. Also, the neutrophil:lymphocyte ratio of NF calves was elevated on d 3 after insertion of the nose flaps compared with baseline, but showed no change for GR calves on any sampling day. Overall, results point toward a favorable effect of a gradual weaning strategy on reduction of weaning and separation distress in dam-reared dairy calves, but the method requires further improvement from the protocol used in our study.

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The world population is growing exponentially, increasing demand to produce high-quality protein for human consumption. Changes in weather patterns, drought, and decreased land resources due to urbanization have increased the strain on the agriculture sector to meet world demands. An alternative method to combat these issues and continue to produce high-quality livestock feed would be through a controlled environment vertical farming system. Commonly, cereal grains, such as barley, are used in these systems to produce livestock feed. However, there is little information on the viability of feeding sprouted grains to beef cattle. Two diets of either feeder-quality alfalfa hay (n = 10 pairs; ALF) or the same alfalfa hay and sprouted barley (SB; 12.6% dry matter [DM]; n = 10 pairs) were fed for 90 d to Angus pairs with a steer calf during mid to late lactation. On days 0 and 90, body weight (BW), milk, rumen fluid, and body condition score were collected from cows and hip height and BW were recorded for calves. On day 10, BW was recorded for cows and calves and rumen fluid was collected from cows. Rumen fluid was also collected from cows on day 45. On day 55, BW was collected for both cows and calves and milk from cows. Intake was recorded throughout the trial via bunks with Vytelle technology. The PROC MIXED procedure of SAS was used to analyze all data with the day as a repeated measure to determine the main effect of diet. Individual volatile fatty acids (VFA) were measured as a percent of total VFA. No differences (P ≥ 0.16) were observed in calf BW, hip height, milk protein, fat, lactose, calf DM intake (DMI), or cow DMI. Cows fed SB tended (P = 0.08) to have a decreased somatic cell count compared to ALF. Percent butyrate was impacted by diet × day (P = 0.02), but no difference (P > 0.09) at any time points were detected. Additionally, a diet × day effect (P = 0.001) on rumen pH demonstrated that both groups stayed consistent until day 45 and then SB pH decreased the last 45 d. There was a day effect for total VFA (P = 0.0009), acetate:propionate (Ac:Pr; P < 0.0001), acetate (P < 0.0001), and propionate (P < 0.0001) demonstrating that total VFA, acetate, and Ac:Pr all increased throughout the trial, while propionate decreased. These results indicate that SB can be a potential alternative feed at this stage of production as it does not negatively impact health or production, but does affect the rumen pH and proportion of some VFA.

Climate variability and uncertainty associated with weather patterns can greatly impact feed security for cattle producers. Flooding, drought, and temperature extremes can reduce a farmer's ability to produce a consistent crop, resulting in feed prices that can fluctuate greatly. Vertical farming systems that sprout cereal grains in a controlled environment, using precision irrigation, may alleviate the effects of external factors such as climate and resulting feed prices. The objective of this study was to determine if sprouted barley (SB) could be used as an effective alternative feed source for cow-calf pairs. Two diets were fed to 20 cow-calf pairs, a control diet consisting of 100% feeder-quality alfalfa hay, or an experimental diet comprised of feeder-quality alfalfa hay and a 12.6% dry matter inclusion of SB for 90 d. Body weight, feed intake, and feeding behavior were analyzed in the cows and calves. Ruminal health was also assessed in cows by analyzing the ruminal fluid for pH and volatile fatty acid composition. When health and performance metrics were analyzed, no differences were found between the two diets that were administered to the cattle.

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BACKGROUND: Data on antimicrobial resistance (AMR) in cow-calf herds is limited and there have been no Canadian studies examining AMR in Enterococcus in cow-calf herds. Enterococcus is a ubiquitous Gram-positive indicator of AMR for enteric organisms that is also important in human health. The objective of this study was to describe AMR in specific Enterococcus species of interest from cow-calf herds; highlighting differences in AMR among isolates from cows and calves and samples collected in the spring and fall. Isolates (n = 1505) were examined from 349 calves and 385 cows from 39 herds in the spring of 2021 and 413 calves from 39 herds and 358 cows from 36 herds in the fall of 2021. Enterococcus species were identified using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight mass spectrometry (MALDI-TOF MS) and antimicrobial susceptibility testing was completed based on a prioritization scheme for importance to human health and using the National Antimicrobial Resistance Monitoring System (NARMS) Gram positive Sensititre broth microdilution panel. RESULTS: Resistance was observed to at least one antimicrobial in 86% (630/734) of isolates from the spring and 84% (644/771) of isolates from the fall. The most common types of resistance across all species were: lincomycin, quinupristin/dalfopristin, daptomycin, ciprofloxacin, and tetracycline. However, the proportion of isolates with AMR varied substantially based on species. Multiclass resistance, defined as resistance to ≥3 antimicrobial classes after excluding intrinsic resistance, was highest in isolates from calves in the spring (6.9%) (24/349) and cows in the fall (6.7%) (24/357). Differences in resistance were seen between cows and calves in the spring and fall as well as across seasons, with no differences seen between cows and calves in the fall. CONCLUSIONS: While most Enterococcus isolates were resistant to at least one antimicrobial, questions remain regarding species differences in intrinsic resistance and the accuracy of certain antimicrobial breakpoints for specific Enterococcus spp. As a result, some species-specific AMR profiles should be interpreted with caution. Despite these constraints, Enterococcus species are important indicator organisms for AMR and resulting data can be used to inform stewardship initiatives.

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The practice of keeping dairy cows with their calves continues to gain interest. Cow-calf contact, or lack thereof, is expected to affect emotional states, but this requires empirical testing. Different types of cow-calf contact may also affect the emotional states of cows. The primary objective of this study was to assess the emotional state of dairy cows with full-time (23 h/d), part-time (10 h/d), or no-contact with their calves (separated 48 h after birth), using a visual judgment bias test (JBT) about one month after calving; JBT is the current gold-standard method to assess emotional state in animals by evaluating optimism or pessimism (illustrated by the proverbial half-full or half-empty water glass). The secondary objective was to compare outcomes of color- versus shape-based visual JBT. Fifty dairy cows were trained to approach a positive image on a screen (rewarded with food) and to avoid a negative image (else punished with waving bag). Once learned (>80% correct over 2 consecutive days), cows were presented with 3 ambiguous images (each presented once per day among 4 positive and 3 negative images, repeated over 4 d), and their approach responses recorded. For the color method (10 full-time, 9 part-time and 11 no-contact cows), positive and negative images were a solid red or white background; ambiguous images were shades of pink. For the shape method (8 full-time, 6 part-time and 6 no-contact cows), positive and negative images were a white circle or cross on a black background; ambiguous images were overlaid circle and cross in varying shades of gray. Cows learned to discriminate colors quicker than shapes (7.3 d, confidence limits [CL]: 6.6-8.2 d; vs. 9.3 d, CL: 8.1-10.6 d). Approaches to ambiguous colors followed a generalization curve (81.0, 33.1, and 5.0 ± 3.7% for near-positive, middle, and near-negative images, respectively), but not approaches to ambiguous shapes (31.9%, 25.7%, and 21.9% ± 4.8%, respectively), indicating colors over shapes should be used in visual JBT for cattle. Part-time cows approached fewer ambiguous color images than full-time cows (23.5%, CL: 13.4%-34.4%; vs. 44.8%, CL; 32.8%-57.1%) whereas no-contact cows were intermediate, but not different from full-time or part-time cows (37.8%, CL; 26.8%-49.5%). The color JBT results show a pessimistic bias (indicating a negative emotional state) in cows with part-time calf contact, possibly due to repeated daily separation from her young calf, relative to cows with full-time calf contact. Thus, cow-calf contact systems appear to influence the emotional state of cows depending on the practice. Cows without calf contact showed no difference in judgment bias between cows with full- or part-time calf contact, suggesting these cows probably do not experience a pervasive negative emotional state (relative to those with calf contact) approximately 30 d after calf separation. However, individual variability in judgment bias was evident for all treatments. The visual judgment bias test is a useful methodology for assessing emotional states of dairy cows; future research should prioritize understanding the emotional states of dairy cows in alternative management systems.

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A positive mood in humans tends to broaden attentional scope while negative mood narrows it. A similar effect may be present in non-human animals; therefore, attentional scope may be a novel method to assess emotional states in livestock. In this proof-of-concept exploratory study, we examined the attentional scope of dairy cows housed with their calves either full-time, part-time (during daytime only), or with no calf contact (enrolled n = 10 each). Housing conditions were previously verified to induce differences in positive and negative emotional state, where part-time was considered more negative. Cows were trained to approach or avoid hierarchical images on a screen that were consistent in local and global elements (i.e., 13 small circles or crosses arranged in an overall circle or cross). After discrimination learning (>80% correct, over two consecutive days), 14 cows proceeded to test (n = 6 each full-and part-time; n = 2 no-contact, not analyzed). Test images showed inconsistent combinations of global and local elements (i.e., the overall global shape differs from the smaller local elements, such as a global circle composed of smaller local crosses and vice versa). Over two test days, approach responses to global and local images (each presented four times) were recorded. All cows were more likely to approach the local than the global image, especially part-time cows who never approached the global image; this may reflect a narrowed attentional scope in these cows. Full-time cows approached images more often than part-time cows, but overall response rates to global and local images were low, making specific conclusions regarding attentional scope difficult. Different housing conditions have potential to affect attentional scope, and possibly emotional state, of dairy cows, but statistical comparison to no-contact treatment was not possible. Cortisol concentration did not affect responses to images; thus arousal due to treatment or test conditions could not explain test performance. Further work with refined methodology and a larger sample size is required to validate the reliability of attentional scope as an assessment method of emotional state in cattle. Beyond this, the attentional scope test revealed how cattle may process, learn and respond to different visual hierarchical images, which further our understanding of cognitive and visual processes in cattle.

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Escherichia coli O157:H7 is a human pathogen that exists as part of the commensal microflora of cattle and is shed in animal feces. Little is known about the effect of management practices on its occurrence and transmission on small-scale cow-calf operations. Identification of risk factors associated with farm practices could help implement effective measures to control E. coli O157:H7. This study quantified the risk of E. coli O157:H7 occurrence associated with cow-calf farm practices using risk modeling. Management practices of small-scale cow-calf operations in OK and LA were assessed through survey-based research. Fecal, water, sediments and water-trough-swab samples were collected to determine the incidence of E. coli O157:H7, and potential on-farm contamination sources and risk factors identified. Association between the occurrence of pathogen and farm practices was determined using two risk assessment models (I and II). Model I determined the association of E. coli O157:H7 occurrence with water source, water container, feed, cattle breed, and herd density, while Model II determined its association with farm cleanliness. For both models, logistic regression was followed using a two-step approach, univariable and multivariable analysis. In OK and LA, E. coli O157:H7 was present in 5.8% and 8.8% fecal, 4.4% and 9.4% water, 10.3% and 9.6% sediments, and 1.5% and 10.6% water-trough-swab samples, respectively. In Model I, univariable analysis identified water container and feed, whereas multivariable analysis identified feed as a significant risk factor. In Model II, the univariable analysis found cleanliness of cattle-contact areas, such as, alleyways, water-trough, chute and equipment, to be a significant risk factor. In multivariable analysis, only the cleanliness of water-trough was identified to be a significant risk factor. Results from the study could aid in the development of on-farm best management practices for the reduction of E. coli O157:H7.

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Omphalitis is the third most frequent disease in newborn calves after neonatal diarrhea and bovine respiratory disease (BRD), but limited data on the prevalence and risk factors are available in the literature. Failure of passive immunity transfer (FPIT) is recognized as a major risk factor for diseases and mortality in calves. However, the association between omphalitis and FPIT remains poorly described. To assess this association, 964 suckler beef calves from 22 farms were included in a longitudinal cohort study for 5 months. Each calf was examined twice (mean ages: 4.4 and 11.1 days old) to diagnose omphalitis through clinical examination and ultrasonographic evaluation (USE) if necessary. Measurements of the total solids percentage (TS-%Brix) and total protein (TP) were performed on the serum during the first visit to evaluate the calves' passive immunity status. FPIT (fair and poor) was defined as serum %Brix < 8.1 or TP < 5.1 g/dL; among calves with omphalitis, 14% had FPIT and among calves without omphalitis 12% had FPIT. The omphalitis prevalence was 32.3% in calves without any other disease (overall prevalence of 30.9%). No statistical association between the prevalence of omphalitis and FPIT was observed. Further research is needed to identify the risk factors and promote the prevention measures for omphalitis in cow-calf systems, such as calving difficulty, hygiene of housing, and navel disinfection.

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This study investigated cow-calf productivity in a 10-week, pasture-based, extended suckling system featuring part-time cow-calf contact and once-a-day milking. A total of 30 dairy cows and their calves were assigned to two treatments: (1) cow and calf managed in an extended suckling system; or (2) cow and calf separated at birth and managed as usual. Cow-calf pairs grazed together during the day and spent the night separated by fence-line contact. The dams were reunited with the calves after once-a-day milking every morning. The commercial treatment pairs were separated after birth, and cows were milked twice a day and managed within the farm herd. Commercial calves were reared and managed as per commercial Australian practices. Cow-calf dams yielded 9 L/cow/day less saleable milk (p < 0.001), and their milk had lower fat (p = 0.04) but a higher protein percentage (p < 0.001) than commercial cows during pre-weaning. However, milk yield and composition were comparable post-weaning. Dam-suckled calves gained weight faster and were therefore weaned 2 weeks earlier than commercial calves, which were offered 8 L/day milk. This study has demonstrated a novel system of extended cow-calf suckling that could be practical to implement in pasture-based dairies. The long-term effects and scalability of the extended suckling system described here require further validation.

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Allowing the dam to rear her calf is an alternative practice in the dairy industry where cow and calf may gain welfare benefits from performing natural and highly motivated behaviors. However, this system has been linked to an increased separation and weaning response. Reducing the daily dam-calf contact time may be a way to prepare the calf for weaning and separation. The first aim of the present study was to investigate the effect of 8 wk of half-day dam-calf contact on calf response to weaning and separation, compared with calves reared with whole-day dam-calf contact and an artificially reared, group-housed control with unrestricted access to milk for 20 min twice daily. Weaning off milk and separation from the dam can be viewed as 2 independent stressors. By introducing each stressor separately, it may be possible to reduce the overall behavioral response. The second aim of the present study was to investigate the effect of 1-wk fence-line weaning before permanent separation. The study was conducted with a 3 × 2 factorial design with dam contact treatments (whole-day, half-day, and control) and weaning treatments (simultaneous, and stepwise). Whole-day calves were separated twice daily from their dams during milking, whereas half-day calves were separated daily from the afternoon milking and until next morning milking. Simultaneous weaning and separation were done in wk 9, and stepwise weaning and separation started in wk 8 with calves being fence-line weaned before permanent separation in wk 9. Data were collected on 69 dairy calves in wk 8 and wk 9, and data were summarized over the 2 weeks for analysis. Stepwise weaning and separation reduced the number of high-pitched vocalizations and activity of dam-reared dairy calves but had little effect on control calves. There was no difference between whole-day and half-day calves in their response to separation, but as expected, dam-reared calves reacted more strongly than the control group. This was also reflected in the average daily BW gain the week after weaning, with control calves having higher average daily gains than whole-day, while half-day calves were intermediate. However, the behavioral response did not fully wane within the observation period (0-48 h of interventions). In conclusion, 1-wk fence-line weaning reduced the summed weaning and separation response in dam-reared calves. However, no difference between half-day dam-calf contact and whole-day dam contact was detected in the behavioral response to weaning and separation.

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Obtaining accurate body weight (BW) is crucial for management decisions yet can be a challenge for cow-calf producers. Fast-evolving technologies such as depth sensing have been identified as low-cost sensors for agricultural applications but have not been widely validated for U.S. beef cattle. This study aimed to (1) estimate the body volume of mature beef cows from depth images, (2) quantify BW and metabolic weight (MBW) from image-projected body volume, and (3) classify body condition scores (BCS) from image-obtained measurements using a machine-learning-based approach. Fifty-eight crossbred cows with a mean BW of 410.0 ±â€…60.3 kg and were between 4 and 6 yr of age were used for data collection between May and December 2021. A low-cost, commercially available depth sensor was used to collect top-view depth images. Images were processed to obtain cattle biometric measurements, including MBW, body length, average height, maximum body width, dorsal area, and projected body volume. The dataset was partitioned into training and testing datasets using an 80%:20% ratio. Using the training dataset, linear regression models were developed between image-projected body volume and BW measurements. Results were used to test BW predictions for the testing dataset. A machine-learning-based multivariate analysis was performed with 29 algorithms from eight classifiers to classify BCS using multiple inputs conveniently obtained from the cows and the depth images. A feature selection algorithm was performed to rank the relevance of each input to the BCS. Results demonstrated a strong positive correlation between the image-projected cow body volume and the measured BW (r = 0.9166). The regression between the cow body volume and the measured BW had a co-efficient of determination (R2) of 0.83 and a 19.2 ±â€…13.50 kg mean absolute error (MAE) of prediction. When applying the regression to the testing dataset, an increase in the MAE of the predicted BW (22.7 ±â€…13.44 kg) but a slightly improved R2 (0.8661) was noted. Among all algorithms, the Bagged Tree model in the Ensemble class had the best performance and was used to classify BCS. Classification results demonstrate the model failed to predict any BCS lower than 4.5, while it accurately classified the BCS with a true prediction rate of 60%, 63.6%, and 50% for BCS between 4.75 and 5, 5.25 and 5.5, and 5.75 and 6, respectively. This study validated using depth imaging to accurately predict BW and classify BCS of U.S. beef cow herds.

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This study examined the influence of management practices and herd demographics on calf mortality proportions in Western Canadian cow-calf operations, utilizing data from the second Western Canadian Cow-calf Survey. The survey was conducted between October 23, 2017, and February 28, 2018. The survey, which was open to all cow-calf producers across Western Canada, provided producer-reported data regarding calf death loss and corresponding herd-level factors. A fractional logit model was employed to identify significant factors associated with calf mortality proportions. The findings revealed that shorter breeding seasons (<63 days), calves born within the same season, and regular pregnancy checks for breeding females were negatively associated with calf mortality proportions. Conversely, regular breeding soundness evaluations for breeding bulls, traditional weaning methods, and vaccinating heifers for scours showed positive associations with increased calf mortality proportions. Herd operations where dams were vaccinated against clostridial and bovine respiratory diseases had lower calf mortality proportions. Notably, operations with experienced primary decision-makers holding off-farm jobs had lower predicted calf mortality proportions compared to those managed by full-time cattle producers. Higher predicted calf mortality proportions were observed in operations employing a backgrounding system. The study's limitations included potential biases due to its cross-sectional nature and reliance on producer-reported data, which might lead to an underestimation of calf mortality proportions. Also, the limited sample size and missing data might have affected the statistical significance of some variables. This study contributed to the research on cow-calf operation by using a fractional logit model to analyze the correlation between risk factors and calf mortality proportions, and by identifying novel herd-level risk factors. It provided a basis for future research aimed at developing empirically-based management strategies to optimize calf health outcomes.

RESUMEN

Vaccinations are one of the most impactful tools available to cow-calf producers to control within herd disease and later, in feedlots. While vaccine use has been studied across Canada, inconsistent and variable regional data makes analysis and interpretation difficult. The objective of this study was to describe vaccination protocols and factors associated with vaccine use in Canadian cow-calf herds and define associations between vaccine use and productivity outcomes. Surveys describing vaccine use in 2020 were collected from 131 cow-calf herds (40 eastern, 91 western), recruited through a national beef cattle surveillance program. Ninety-two percent of cows and replacement heifers, and 72% of bulls were vaccinated with Infectious Bovine Rhinotracheitis (IBR), Bovine Viral Diarrhea Virus (BVDV), Parainfluenza3 Virus (PI3), and Bovine Respiratory Syncytial Virus (BRSV). At least half of cows and bulls were vaccinated for clostridial pathogens and cows and heifers for viral calf scours. Clostridial vaccines were significantly more likely to be used in western Canada compared to eastern Canada. While 92% of producers vaccinated suckling calves against IBR/BRSV/PI3, only 47% provided a second vaccine prior to weaning; 78% of calves were also vaccinated at least once for BVDV before weaning. Producers who vaccinated calves against IBR/BRSV/PI3 before 3 months of age provided a second dose prior to weaning more often than producers who administer the first IBR/BRSV/PI3 vaccine later. Vaccine use has increased across Canada, particularly in calves, prior to weaning. Relative to label recommendations for annual vaccination, clostridial vaccines were generally underutilized in cows and bulls, and by producers in eastern Canada as compared to western Canada. Opportunities also exist to improve adherence to label recommendations for the booster dose of scours vaccine when used in bred replacement heifers. Protocols including product choices, the timing and boosting of respiratory vaccines in nursing calves vary widely across herds. Use of intranasal vaccines in neonatal calves less than 2 weeks old has increased in western Canada compared to previous reports. There is a need to better understand how timing of vaccination in nursing calves contributes to effectiveness, for respiratory disease in nursing and weaned calves.

RESUMEN

Trace mineral supplementation of beef cattle is essential for efficient reproduction and herd health. Understanding regional differences in cow trace mineral status could inform decisions about risks of deficiencies and supplementation management. Cow-calf surveillance projects provided three opportunities to evaluate the trace mineral status of Canadian beef cow herds. Blood samples were collected at pregnancy testing in 2014 from 102 cow-calf herds and in 2016 from 86 cow-calf herds in Western Canada. In 2019, blood samples were collected at pregnancy testing from cows in 163 cow-calf herds from Eastern and Western Canada. Serum samples were analyzed for copper, selenium, and molybdenum concentrations using a plasma mass spectrometer. The prevalence of copper deficient cows sampled from the Western provinces ranged from 24% to 43% across the three periods, and was 20% from Eastern Canada in 2019. The prevalence of selenium deficient cows ranged from 0.2% to 0.4% across the three projects in Western Canada, but was higher in Eastern Canada at 4.6% in 2019. High serum molybdenum was identified in 9.4% to 14% of cows across the three periods in Western Canada and in 15% of cows sampled in Eastern Canada in 2019. Serum copper, selenium, and molybdenum concentrations varied by cow age and month of sample collection. Serum selenium and molybdenum concentrations, but not copper, varied by soil type associated with the location of the farm. A subsample of samples from cows from Western Canadian herds provided body condition score (BCS) data, pregnancy status, and calf survival data and were used to estimate updated serum reference values for adequate concentrations. Age-specific values were required for selenium and molybdenum. Reference intervals (80%) were estimated from 2,406 pregnant beef cows from 99 herds with each cow having a BCS ≥ 2.5/5 and a live calf at 3 wk with no retained placenta: copper for all cows (0.379 to 0.717 ppm), selenium for cows <4 yr (0.052 to 0.152 ppm), and selenium for cows ≥4 yr (0.064 to 0.184 ppm). Upper 90% reference limits were also estimated for serum molybdenum for cows <4 yr (>0.104 ppm) and cows ≥4 yr (>0.110 ppm). The lower limits for the reference intervals for adequate copper and selenium are below those previously reported; nevertheless, they represent a large sample that was specifically applicable to extensively managed beef animals in western Canada.

RESUMEN

Our objectives were to evaluate the impacts of providing vitamin and mineral (VTM) supplements to cow-calf pairs during the summer grazing period on cow and calf performance and liver concentrations of minerals. During a two-year period, 727 crossbred cows and their calves (initial cow BW = 601.7 ± 48.1 kg; calf BW = 87.8 ± 5.0 kg; n = 381 in year 1, n = 346 in year 2) from the Central Grasslands Research Extension Center (Streeter, N.D.) were blocked by parity (young [parity 1 to 3], and old [parity 4+]) and randomly assigned to pastures at the beginning of the grazing season (16 in year 1 and 14 in year 2). Pastures were assigned to receive a free-choice VTM supplement (SUPP) or no VTM supplement (CON) from pasture turnout to pasture removal (158 and 156 days in year 1 and 2, respectively). Consecutive day weights were taken from cows and calves at pasture turnout and removal and liver biopsies were collected from a subset of cows at both timepoints and from calves at weaning. Cows were bred via AI 37 to 41 d after pasture turnout and by natural service cleanup bulls for a 70 to 80 d breeding season. Calving and weaning data were collected from the calf conceived and gestated during treatments. Data were analyzed for the effect of VTM treatment (SUPP vs. CON), block of parity, and their interaction using the GLM procedure of SAS with pasture as the experimental unit. Year was considered a random effect in the final analysis. Cow pregnancy success was evaluated using the GLIMMIX procedure in SAS with model terms of VTM treatment, parity, and their interaction with year as a random effect. In year 2, cows in differing days postpartum (DPP) groups at pasture turnout (66.1, 48.8, and 34.5 ± 1.04 DPP for EARLY, MID, and LATE groups, respectively) were selected for liver biopsies with cow as the experimental unit. Cow and calf BW and BW change were not impacted (P ≥ 0.20) by VTM access. Pregnancy rate to AI, overall pregnancy rate, gestating calf birth BW and calving distribution were not affected (P ≥ 0.11) by treatment. Liver concentrations of Se, Cu, and Co were greater (P ≤ 0.002) at pasture removal and weaning for cows and suckling calves that had access to VTM. Cows considered EARLY calving had greater (P = 0.05) concentrations of liver Se compared with LATE calving cows. Although VTM supplementation enhanced concentrations of key minerals in the liver of cow-calf pairs, reproductive and growth performance was not affected.