Effect of suckler cow breed type and parity on the development of the cow-calf bond post-partum and calf passive immunity.

BACKGROUND: Development of the cow-calf bond post-partum and passive immunity of calves from spring-calving beef × beef (B×B) and beef × dairy (B×D) cow genotypes was determined using primiparous and multiparous (Experiment 1), and primiparous and second-parity (Experiment 2) animals. In Experiment 1, calves either suckled colostrum naturally ('natural-suckling') (n = 126), or were fed colostrum, using an oesophageal-tube ('artificially-fed') (n = 26), from their dam within 1-h post-partum. In Experiment 2, all calves (n = 60) were artificially-fed colostrum from their dam. Prior to colostrum suckling/feeding, colostrum was sampled for IgG analysis. The cow-calf bond was assessed using CCTV recordings during the first 4-h post-partum. Calves were blood sampled at 48-h post-partum to determine IgG and total protein (TP) concentrations, and zinc sulphate turbidity (ZST) units. RESULTS: There was no difference (P > 0.05) in cow licking behaviours and calf standing and suckling behaviours between the genotypes, except in Experiment 2 where B×D calves had more attempts to suckle before suckling occurred (P ≤ 0.05) compared to B×B calves. In Experiment 1, multiparous cows licked their calves sooner (P ≤ 0.05) and for longer (P < 0.01), and their calves had fewer attempts to stand (P < 0.001), stood for longer (P = 0.05), and had fewer attempts to suckle before suckling occurred (P < 0.001) than primiparous cows; there was no parity effect on cow-calf behaviour in Experiment 2. Colostrum IgG concentrations and measures of calf passive immunity did not differ (P > 0.05) between the genotypes in either Experiment. In Experiment 1, colostrum IgG concentrations were greater (P ≤ 0.05) in multiparous compared to primiparous cows and their calves had superior (P ≤ 0.05) passive immunity; no effect of parity was found in Experiment 2. Passive immunity did not differ (P > 0.05) between suckled and artificially-fed calves in Experiment 1. CONCLUSIONS: Cow genotype had little effect on cow-calf behaviours, but under 'natural-suckling' conditions primiparous cows expressed maternal inexperience and their calves were less vigorous than multiparous cows. Colostrum IgG concentration and calf passive immunity measures were unaffected by genotype, but under 'natural-suckling' conditions calves from primiparous cows had lower passive immunity.

The Canadian Cow-Calf Surveillance Network - productivity and health summary 2018 to 2022.

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.

The effects of including sprouted barley with alfalfa hay in the diet on ruminal health and performance of cow-calf pairs.

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.

Concentrations of antimicrobial components in milk of Japanese Black cows and their differences from dairy cows.

The components of milk from beef cows remain to be elucidated. This study examined the differences in the antimicrobial components of milk between dairy and beef cows. Quarter milk was collected from both Japanese Black (beef type) and Holstein (dairy type) cows to compare the concentrations of antimicrobial components. The concentration of lingual antimicrobial peptide (LAP) was higher, whereas that of the other antimicrobial components (lactoferrin, S100A7, and S100A8) was lower in beef cows than in dairy cows. Overall, these results indicate that the differences in antimicrobial components between beef and dairy cows may be associated with the difference in the prevalence of mastitis between them.

Predicting feed intake in confined beef cows.

Six existing equations (three for nonlactating and three for lactating; NRC, 1987, Predicting feed intake of food-producing animals. Washington, DC: The National Academies Press, National Academy of Science; doi: 10.17226/950; NRC, 1996, Nutrient requirements of beef cattle, 7th Revised Edition: Update 1996. Washington, DC: The National Academies Press; doi: 10.17226/9791; Hibberd and Thrift, 1992. Supplementation of forage-based diets. J. Anim. Sci. 70:181. [Abstr]) were evaluated for predicting feed intake in beef cows. Each of the previously published equations are sensitive to cow-shrunk BW and feed energy concentration. Adjustments in feed intake prediction are provided for level of milk yield in NRC (1987. Predicting feed intake of food-producing animals. Washington, DC: The National Academies Press, National Academy of Science; doi: 10.17226/950) and NRC (1996 Nutrient requirements of beef cattle, 7th Revised Edition: Update 1996. Washington, DC: The National Academies Press; doi: 10.17226/9791) equations. The equation published in 1996 used data generated between 1979 and 1993. Our objectives were to validate the accuracy of the published equations using more recent data and to propose alternative prediction models. Criteria for inclusion in the evaluation dataset included projects conducted or published since 2002, direct measurement of feed intake, adequate protein supply, and pen feeding (no metabolism crate data). After removing outliers, the dataset included 53 treatment means for nonlactating cows and 32 treatment means for lactating cows. Means for the nonlactating dataset were dry matter intake (DMI) = 13.2 ±â€…2.9 kg/d, shrunk body weight (SBW) = 578 ±â€…83.9 kg, body condition score = 5.7 ±â€…0.73, and Mcal net energy for maintenance (NEm)/kg of feed = 1.27 ±â€…0.15 Mcal/kg. Means for the lactating dataset were DMI = 14.6 ±â€…2.24 kg/d, SBW = 503 ±â€…73.4 kg, body condition score = 4.7 ±â€…0.58, and Mcal NEm/kg feed = 1.22 ±â€…0.16. Simple linear regression was used to determine slope, intercept, and bias when observed DMI (y) was regressed against predicted DMI (x). The NRC (1996. Nutrient requirements of beef cattle, 7th Revised Edition: Update 1996. Washington, DC: The National Academies Press; doi: 10.17226/9791) nonlactating equation underestimated feed intake in diets moderate to high in energy density with intercept differing from 0 and slope differing from one (P ≤ 0.01). Average deviation from observed values was 2.4 kg/d. Similarly, when the NRC (1996. Nutrient requirements of beef cattle, 7th Revised Edition: Update 1996. Washington, DC: The National Academies Press; doi: 10.17226/9791) equation was used to predict DMI in lactating cows, the slope differed from one (P < 0.01) with average deviation from observed values of 3.0 kg/d. New models were developed by pooling the two datasets and including a categorical variable for stage of production (0 = nonlactating and 1 = lactating). Continuous variables included study-average SBW0.75 and diet NEm, Mcal/kg. The best-fit empirical model accounted for 68% of the variation in daily feed intake with standard error of the estimate Sy root mean squared error = 1.31. The proposed equation needs to be validated with independent data.

Intake, Digestibility, Ruminal Fermentation, and In Situ Disappearance of Bermudagrass Hay by Lactating Beef Cows Offered Corn or Hominy Feed as Supplements at Two Different Rates.

Hominy feed (HF) has been evaluated in feedlot and dairy rations but has not been evaluated as a supplemental energy source for lactating beef cows. The objective of this study was to determine the effect of level of HF supplementation on intake, digestibility, ruminal fermentation characteristics, and in situ dry matter (DM) disappearance of bermudagrass hay. Five ruminally cannulated lactating beef cows (body weight (BW) = 596 kg, SE = 13.9) were used in an experiment with a 5 × 5 Latin square design. Treatments were a bermudagrass hay-basal diet with low HF (LH; 0.25% BW), medium HF (MH; 0.50% BW), low ground corn (LC; 0.25% BW), medium ground corn (MC; 0.50% BW) and no supplement (CON). Cows were housed individually, and supplements were offered at 0800 daily. Hay was offered to maintain 10% refusal. Periods were 16-d, with 10 d for adaptation. Ruminal fluid was sampled on d 14 of each period for measurement of pH, volatile fatty acids, and rumen ammonia-N. An in situ degradation experiment for bermudagrass hay was completed for each diet. Hay dry-matter intake (DMI % BW) was not affected (p = 0.14) by supplement, but total DMI (DMI % BW) was greater (p ≤ 0.05) in MH and MC compared to LH and CON. Digestible DMI % BW was greater (p = 0.05) in MH compared to LC, MC was intermediate, and LH and CON were lesser (p ≤ 0.01) than all other diets. Dry-matter fill, passage rate, and retention time did not differ by diet (p ≥ 0.31). A diet × time interaction was observed for ammonia-N (p = 0.0002), and propionate (p = 0.02) time effects were observed for other parameters, but no diet effects. Bermudagrass hay's potentially degradable fraction was greater (p ≤ 0.05) in LH than MH and CON, but effective DM degradability was not different (p = 0.39) among diets. Overall, no diets reduced hay intake or disappearance compared to CON; therefore, no negative associative effects were observed from any of the supplements at the levels offered in this study.

A Scoping Review of Antimicrobial Usage and Antimicrobial Resistance in Beef Cow-Calf Herds in the United States and Canada.

BACKGROUND: The magnitude and knowledge gaps regarding antimicrobial use (AMU) and antimicrobial resistance (AMR) have not been summarized for the North American cow-calf production sector, although estimates of AMU and AMR are essential to AMR risk analysis. The objectives of this scoping review were to map AMU and AMR in the beef cow-calf sector in Canada and the United States, summarize published AMU/AMR predictors, and identify research gaps. METHODS: An electronic search was conducted of four bibliographic databases and Google Scholar, augmented by a hand-search of captured studies. RESULTS: Twenty-three of three-hundred and forty-three publications screened advanced to data extraction. Of these, 10 were conducted in the USA and 13 in Canada. Thirteen studied AMR and twelve studied AMU, with two reporting both. Of twelve captured AMU studies, nine presented counts of herd AMU by antimicrobial class or specific antimicrobial. Antimicrobial resistance in Escherichia coli (E. coli) was reported in nine studies. Risk factors for AMU include herd size, vaccine use, and start date of calving season. CONCLUSIONS: Overall, a small number of AMR studies were available for synthesis in primarily one population (cows) reporting E. coli AMR. Additional studies targeting reasons for AMU in calves, the impact of management procedures on AMU, potential environmental AMR sources, and AMR in respiratory pathogens and enteric organisms other than E. coli for pre-weaning calves are required to inform AMR risk mitigation strategies.

The probability distributions of the movement of dairy and beef cattle in Japan: a data note.

OBJECTIVES: Animal movement is an important factor in the transmission of infectious diseases among livestock. A better understanding of animal movement characteristics provides a more reliable estimation of disease spread and promotes modeling studies. In Japan, all the cattle movement information is recorded in a national database called the Individual Cattle Identification Register (ICIR)." Our previous studies using this information demonstrated heterogeneity in the movement of dairy and beef cows according to location, season, and age. The present study describes the probability distributions of the movement of Japanese dairy and beef cows in the following month on a regional basis. DATA DESCRIPTION: This publication contains four probability distribution datasets for the predicted locations of dairy and beef cows in Japan in the following month, which were developed using individual cattle movement information obtained from the ICIR. These datasets provide information on cattle movement in the following month on a regional basis, given properties such as birth region, location, time, and age.

Region-wise analysis of beef cow movements in Japan.

Animal movement is an important factor in the transmission of animal infectious diseases. A better understanding of movement patterns is therefore necessary for developing effective control measures against disease spread. In Japan, a cattle tracing system was established in 2003, following a bovine spongiform encephalopathy epidemic, and the information on all cattle movements has been stored in a national database maintained by the National Livestock Breeding Center. Using these data, we previously analyzed the movement of dairy cows, concluding that heterogeneities in cattle movement are associated with regional and seasonal factors. In the present study, we aimed to identify specific factors affecting the regional and seasonal movement patterns of beef cows in Japan. From April 2012 to March 2017, 797,553 farm-to-farm movement events were recorded. We analyzed movements by month and by cattle age and looked at the frequency of movement within and between seven regions spanning the national territory. Our results show that calf movement peaked at 9-10 months old; these movements were considered to be via the market and were frequent within and between regions. For inter-regional movements, Kyushu region was the top producer of calves for calf trading markets throughout Japan. With regard to intra-regional movements, round-trip movements for summer grazing were observed in May and October for cattle of various ages in the northern regions, especially Hokkaido and Tohoku. Moreover, the movements of Japanese Shorthorn breeds in Tohoku region exhibited consistent annual peaks in May and October/November, in accordance with their seasonal breeding practice. In the areas with high relative densities of dairy cows, such as Hokkaido, the shipping of newborn beef calves produced via embryo transfer to dairy cows was also observed. Overall, understanding the patterns of beef cow movement will help develop effective disease surveillance measures, such as pre-movement inspections focused on specific regions and types of movement.

Environmental stress during the last trimester of gestation in pregnant cows and its effect on offspring growth performance and response to glucose and adrenocorticotropic hormone.

Winter and spring precipitation are predicted to increase in the Midwest region of the United States, causing muddy conditions. In a previous experiment, Angus cows (8 per treatment) were paired based on initial body weight (BW) and one cow from each pair was randomly allocated to either the mud or control treatment. Though cows consumed the same amount of dry matter, cows in the mud treatment weighed 37.4 kg less than cows in the control treatment by day 269 of gestation. The objective of this experiment was to evaluate developmental programming effects of steers born to cows in the mud treatment (MUD; n = 7) or the control treatment (CON; n = 6). Steers were weighed at birth and then weekly from approximately 56 d of age until weaning and were subjected to a glucose tolerance test (GTT) and adrenocorticotropic hormone (ACTH) challenge after weaning. Steers were then placed in the feedlot for an 84-d growing phase and were weighed weekly and 12th rib back fat (BF) and ribeye area (REA) were imaged every 28 d using ultrasonography. Data were analyzed as a randomized complete block design with repeated measurements when appropriate (SAS 9.4). Although there was a 37.4 kg decrease in BW of cows by the end of gestation, there was no evidence of a pen treatment effect on calf birth weight (P = 0.60) or weaning weight (P = 0.99). Additionally, there was no evidence of a pen treatment × day effect for steer BW from birth to weaning (P = 0.67) or growing phase BW (P = 0.60). There was evidence of a treatment × day of growing phase effect (P = 0.02) for BF, such that CON steers had greater BF on day 28 of the growing phase; however, there was no evidence of a treatment × day effect for REA (P = 0.20). Furthermore, there was no evidence of a pen treatment effect for the growing phase average daily gain (P = 0.74), dry matter intake (P = 0.65), gain:feed (P = 0.48), plasma glucose concentration (P = 0.67) or plasma insulin concentration (P = 0.61) in response to the GTT, or plasma cortisol concentration in response to the ACTH challenge (P = 0.51). These results indicate that while mud increased net energy requirements for cows in the MUD treatment, there were no subsequent effects observed for steer BW, gain:feed, or response to glucose and ACTH during the growing phase.

Predictions for the Midwest U.S. indicate that both winter and spring temperatures and precipitation will increase. These climatic changes could result in muddier conditions during winter and spring in the Midwest. It has previously been demonstrated that a muddy environment increases the net energy requirements of mature cow's by approximately 3.9 Mcal/d. If cows are not provided this extra energy and are exposed to mud during late gestation, it is likely that this will cause an adverse environment for the conceptus that could result in compromised growth and metabolism later in life. This study evaluated the developmental programming effects after birth and into the growing phase with beef steers born to cows that were housed in a muddy environment during late gestation compared with steers born to cows that were housed in pens bedded with wood chips during late gestation. Based on the present results, the mature cows housed in the muddy conditions weighed approximately 37.4 kg less than cows housed in pens bedded with wood chips during late gestation, however, calf birth weight, postnatal growth, postnatal feed intake and gain:feed, and postnatal response to glucose and adrenocorticotropic hormone was not affected. This indicates that the mature cows were able to mobilize body stores and supplied the fetus with adequate nutrients during gestation without impairment of growth or postnatal response to glucose and adrenocorticotropic hormone.

Production cow-calf responses from perennial forage-based and integrated beef-cropping systems.

An experiment was conducted to measure production responses of an alternative cow-calf production system integrated into a cropping system without access to perennial forage compared to a traditional cow-calf system utilizing perennial forage. Multiparous, cross-bred beef cows (n = 160; average age = 6.2 ± 2.8 yr) were utilized in a randomized complete block experimental design and unstructured treatment design. Upon initiation, cows were blocked by age and stratified by source, assigned randomly to one of two production systems, each with four replicates (n = 20 cows/replicate). Once allotted to their treatment groups, cows remained in their experimental units for the duration of the experiment. Treatments were: 1) a traditional system consisting of April to May calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to August calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). There were no differences (P ≥ 0.27) in calving rates (91.8 vs. 86.7 ± 2.92%), pregnancy rates (89.3 vs. 89.9 ± 2.66%), and weaning rates (87.2 vs. 82.3 ± 3.29%) for TRAD vs. ALT, respectively. However, there was an increase (P = 0.04) in the rate of twin offspring in ALT (2.9 vs. 9.4 ± 2.36% for TRAD vs. ALT, respectively). One calf from the set of twins was selected randomly at birth to be removed from the experiment, so the production data are only from single calves. There was no difference (P = 0.47) in calf body weight at birth (40 vs. 39 ± 0.7 kg for TRAD vs. ALT, respectively). At weaning, calves in the ALT system were lighter (P < 0.01) at the same day of age (184 vs. 229 ± 5.5 kg) compared to TRAD calves. Cows from the ALT system had fewer (P < 0.01) kg weaned per cow exposed to bull (150 vs. 199 ± 7.2 kg) compared to TRAD cows. Apart from the twinning rate, no differences in reproductive performance were observed among systems. However, reduced weaning weights and kilogram of weaned calf per cow exposed may negatively impact revenue to the cow-calf enterprise of the ALT system.

Preovulatory follicular fluid and serum metabolome profiles in lactating beef cows with thin, moderate, and obese body condition.

Extremes in body condition reduce fertility and overall productivity in beef cattle herds, due in part to altered systemic metabolic conditions that influence the intrafollicular and uterine environment. Follicular fluid and serum metabolome profiles are influenced by body composition in women and dairy cattle; however, such information is lacking in beef cattle. We hypothesized that body condition score (BCS)-related alterations in the metabolome of preovulatory follicular fluid and serum may influence oocyte maturation while impacting the oviductal or uterine environment. Therefore, we performed a study with the objective to determine the relationship between BCS and the metabolome of follicular fluid and serum in lactating beef cattle. We synchronized the development of a preovulatory follicle in 130 cows of varying BCS. We collected blood and performed transvaginal follicle aspirations to collect follicular fluid from the preovulatory follicle ~18 h after gonadotropin-releasing hormone administration to stimulate the preovulatory gonadotropin surge. We then selected follicular fluid and serum samples from cows with BCS 4 (Thin; n = 14), BCS 6 (Moderate; n = 18), or BCS >8 (Obese; n = 14) for ultra-high performance liquid chromatography-high resolution mass spectrometry. We identified differences in the follicular fluid or serum of thin, moderate, and obese animals based on multiple linear regression. MetaboAnalyst 5.0 was used for enrichment analysis of significant metabolites. We identified 38 metabolites in follicular fluid and 49 metabolites in serum. There were no significant differences in follicular fluid metabolite content among BCS classifications. There were 5, 22, and 1 serum metabolites differentially abundant between thin-obese, moderate-thin, and moderate-obese classifications, respectively (false discovery rate [FDR] < 0.10). These metabolites were enriched in multiple processes including "arginine biosynthesis," "arginine/proline metabolism," and "D-glutamine/D-glutamate metabolism" (FDR < 0.04). Pathways enriched with serum metabolites associated with BCS indicate potentially increased reactive oxygen species (ROS) in serum of thin cows. ROS crossing the blood follicular barrier may negatively impact the oocyte during oocyte maturation and contribute to the reduced pregnancy rates observed in thin beef cows.

Extremes in body condition affect fertility and pregnancy outcomes in beef cows. Much research has been done in women and dairy cows to evaluate body condition's effect on oocyte and embryo quality, pregnancy rates, and pregnancy outcomes. However, little work of this type has been done in beef cows and most studies do not focus on the preovulatory time period. The preovulatory time period is an essential time for the oocyte, as final stages of prematuration and the completion of oocyte maturation take place in the peri-ovulatory follicle. The follicular fluid provides the microenvironment for oocyte maturation and exchanges substances with maternal circulation at the blood follicular barrier. Alterations in maternal circulation due to extremes in body condition may pass into the follicular fluid and affect the oocyte during the preovulatory time period. Such conditions may contribute to the reduced fertility seen in beef cows with extreme body condition.

Oversupplying metabolizable protein during late gestation to beef cattle does not influence ante- or postpartum glucose-insulin kinetics but does affect prepartum insulin resistance indices and colostrum insulin content.

The objective of this study was to evaluate whether oversupplying metabolizable protein (MP) during late gestation influences glucose and insulin concentrations, and insulin resistance (IR) in late gestation and early lactation. Crossbred Hereford, first-lactation heifers were individually fed diets to supply 133% (HMP, n = 11) or 100% (CON, n = 10) of their predicted MP requirements for 55 ± 4 d (mean ± SD) prior to calving. All heifers received a common lactation ration formulated to meet postpartum requirements (103% MP and 126% ME). After feed was withheld for 12 h, cattle underwent an intravenous glucose tolerance test (IVGTT) on days -6.7 ± 0.9 and 14.3 ± 0.4 by infusing a 50% dextrose solution (1.36 g glucose/kg BW0.75) through a jugular catheter with plasma collected at -10, 0 (immediately after infusion), 5, 10, 15, 20, 25, 30, 45, 60, 75, 90, and 120 min, respective to the infusion. Glucose and insulin concentrations were assessed. Insulin resistance indices (homeostasis model of insulin resistance [HOMA-IR], quantitative insulin sensitivity check index [QUICKI], revised quantitative insulin sensitivity check index [RQUICK], and RQUICKI incorporating serum beta-hydroxybutyrate concentrations [RQUICKIBHB]) were calculated from measurements of serum non-esterified fatty acids and beta-hydroxybutyrate and plasma glucose and insulin concentrations on days -34 ± 4, -15 ± 4, 7 ± 1, 28 ± 3, 70 ± 3, and 112 ± 3. Colostrum samples were collected within an hour of calving (prior to suckling) and analyzed for insulin concentration. Data were analyzed as a randomized block design using the PROC GLIMMIX of SAS, accounting for repeated measurements when necessary. Baseline (-10 min) plasma glucose and insulin concentrations were elevated (P ≤ 0.038) for HMP heifers during the antepartum IVGTT, but not (P ≥ 0.25) during the postpartum IVGTT. Plasma glucose and insulin concentrations throughout the antepartum or postpartum IVGTT did not differ (P ≥ 0.18) by prepartum treatment, nor did other glucose and insulin IVGTT parameters (i.e., max concentration and time to reach max concentration, nadir values, clearance rates and half-lives, area-under-the-curve, and insulin sensitivity index; P ≥ 0.20). Antepartum IVGTT IR indices indicated that HMP heifers were more (P ≤ 0.011) IR than their counterparts. Similarly, the prepartum HOMA-IR was greater (P = 0.033) for HMP heifers, suggesting increased IR. Postpartum IR indices did not (P ≥ 0.25) indicate that prepartum MP consumption impacted postpartum IR. Colostrum insulin concentration was increased (P = 0.004) by nearly 2-fold for HMP relative to CON heifers. These data demonstrate that prepartum MP overfeeding alters baseline glucose-insulin concentrations in late-pregnant beef heifers and increases colostrum insulin content without having carry-over effects on postpartum glucose-insulin concentrations and IR.

Effect of temporary weaning and creep feeding on calf growth and the reproductive efficiency of their Hereford dams.

OBJECTIVE: The objective was to test if creep feeding (CF) improves the average daily gain (ADG) and weaning weight of calves submitted to temporary weaning (TW) and if the combination of CF and TW improves conception and pregnancy rates of cows. METHODS: Primiparous (n = 74) and primiparous and multiparous (n = 104) cows grazing native grasslands were used in experiment 1 and 2; respectively. The experimental design was in plots divided into complete random blocks with two replications. The CF was the big plot and TW the small plot, thus four experimental groups were formed: i) -CF-TW (n = 21 and 27); ii) -CF+TW (n = 16 and 24); iii) +CF-TW (n = 20 and 26); iv) +CF+TW (n = 17 and 27) with cow-calf pairs for experiments 1 and 2; respectively. Nose plate application for TW had a duration of 14 and 15 days for experiment 1 and 2: respectively. In experiment 1, calves were fed at 1% of live weight for 112 days using a commercial supplement with 18.4% crude protein. In experiment 2, the supplementation lasted 98 days, and was carried out with corn dried distillers grains with soluble (DDGS) at 40% of the potential intake on a daily basis. RESULTS: The TW reduced ADG during the TW period and the following 14 days, but the negative effect of TW was maintained until the final weaning only in experiment 2. The CF increased ADG during TW period in both experiments. The TW promoted an earlier conception of the dams (12 days in -CF treatment and 19 days in +CF treatment, p<0.01) and CF increased pregnancy rate in experiment 1, being the effects not consistent between experiments. CONCLUSION: The CF consistently promoted an increase in ADG during the period of TW and increased final weaning weight of calves, therefore it is economically viable.

Factors affecting placental size in beef cattle: Maternal and fetal influences.

Our objectives were to determine the effects of dam body condition score (BCS), age of dam, and calf sex on placental size and the relationships between dam body weight (BW) and calf size with placental size. Expelled placentas and calf size at birth were collected from crossbred beef heifers and cows during four experiments (n = 22 to 39/experiment). Placentas deemed complete by visual inspection were dissected; dry weights were determined for cotyledonary and intercotyledonary tissues. Mixed linear models were used to individually determine main effects of peripartum BCS category [Thin (<5), Moderate (=5), or Fleshy (≥6)], age of dam category [Primiparous (2 yr), Young (3-4 yr), or Mature (≥5 yr)], and calf sex on placental measures. Correlations were determined for placental characteristics with prepartum dam BW, gestation length, and calf size. Thin BCS dams had lower (P ≤ 0.05) cotyledonary, total placental, and average cotyledon weights and greater placental efficiency (calf birth BW/placental weight) than moderate and fleshy dams. Intercotyledonary weight was lower (P < 0.01) in thin BCS dams compared with fleshy dams. Thin and moderate BCS dams had smaller (P ≤ 0.04) calf birth BW than fleshy dams. Primiparous dams had lower (P ≤ 0.05) total placental and average cotyledon weights than young and mature dams, yet calf birth BW was unaffected (P = 0.17). Male calves were heavier (P = 0.01) than females, yet there were no differences (P ≥ 0.59) in placental weights. Calf birth BW and heart girth had moderate positive correlations (P < 0.01) and shoulder to rump length and abdominal girth had weak positive correlations (P < 0.01) with all placental weights. Dam prepartum BW and calf flank girth had moderate positive correlations (P < 0.01) with total placental weights and weak positive correlations (P < 0.01) with cotyledonary and average cotyledon weights. Intercotyledonary weight had moderate positive correlations (P < 0.01) with gestation length and calf flank girth and a weak positive correlation (P < 0.01) with dam prepartum BW. Gestation length had a weak positive correlation (P = 0.02) with total placental weight. Number of cotyledons was not correlated (P ≥ 0.28) with any dam or offspring characteristics. In conclusion, these data suggest that both maternal age and BCS affected placental size. Calf size at birth and placental weight were positively correlated, but it is still unknown which controls and signals for the growth of the other.

Differential Transcript Profiles in Cumulus-Oocyte Complexes Originating from Pre-Ovulatory Follicles of Varied Physiological Maturity in Beef Cows.

Small dominant follicle diameter at induced ovulation, but not at spontaneous ovulation, decreased pregnancy rate, fertilization rate, and day seven embryo quality in beef cows. We hypothesized that the physiological status of the follicle at GnRH-induced ovulation has a direct effect on the transcriptome of the Cumulus-Oocyte complex, thereby affecting oocyte competence and subsequent embryo development. The objective of this study was to determine if the transcriptome of oocytes and associated cumulus cells (CC) differed among small (≤11.7 mm) and large follicles (≥12.7 mm) exposed to a GnRH-induced gonadotropin surge and follicles (11.7-14.0 mm) exposed to an endogenous gonadotropin surge (spontaneous follicles). RNA sequencing data, from pools of four oocytes or their corresponding CC, revealed 69, 94, and 83 differentially expressed gene transcripts (DEG) among oocyte pools from small versus large, small versus spontaneous, and large versus spontaneous follicle classifications, respectively. An additional 128, 98, and 80 DEG were identified among small versus large, small versus spontaneous, and large versus spontaneous follicle CC pools, respectively. The biological pathway "oxidative phosphorylation" was significantly enriched with DEG from small versus spontaneous follicle oocyte pools (FDR < 0.01); whereas the glycolytic pathway was significantly enriched with DEG from CC pools obtained from large versus small follicles (FDR < 0.01). These findings collectively suggest that altered carbohydrate metabolism within the Cumulus-Oocyte complex likely contributes to the decreased competency of oocytes from small pre-ovulatory follicles exposed to an exogenous GnRH-induced gonadotropin surge.

Fetal programming effects of early weaning on subsequent parity calf performance.

Mature Simmental × Angus cows [n = 147; body weight (BW) = 590 ± 72 kg] were used to evaluate the effects of early weaning on subsequent parity calf growth performance and carcass characteristics. Cows were assigned to one of two treatments based on their previous calf's weaning age: early wean (EW) or conventional wean (CW). Dams assigned to the EW treatment had calves previously weaned at 88 ± 6 d of age, whereas dams assigned to the CW treatment had calves previously weaned at 185 ± 6 d of age. Cow BW and body condition scores (BCS) were monitored during the experiment. All cows were managed as a common group from the onset of the experiment at breeding until final pregnancy check of their next production cycle 462 d later. All calves in the experiment were managed as one group and weaned at a single time point, then feedlot performance and carcass characteristics were evaluated. Initial cow BW was different (P < 0.05), so it was included as a covariate for cow BW analysis. There was a treatment × date interaction (P < 0.01) for cow BW and cow BCS. Cow BW was consistently greater for the EW treatment from day 39 to the end of the experiment (P < 0.01). Cow BCS were not different at the onset of the experiment (P = 0.20), although after breeding and throughout lactation, BCS diverged between treatments and the EW treatment consistently had greater (P < 0.01) BCS than the CW treatment throughout the entire subsequent lactation. Gestation length was not different (P = 0.21) between treatments, yet calf birth BW was greater (P = 0.05) for the EW treatment. Neither artificially inseminated pregnancy percentage nor overall pregnancy percentage was different between treatments (P ≥ 0.61). Despite the greater birth BW for the EW treatment and no difference (P = 0.25) in milk production, weaning BW was not different (P = 0.50) between treatments. Feedlot performance measures were not different (P ≥ 0.13) between treatments, including feedlot arrival weight, final BW, average daily gain, dry matter intake, and gain to feed. Final carcass characteristics were not different (P ≥ 0.33) between treatments, including dressing percentage, hot carcass weight, LM area, 12th rib fat thickness, kidney, pelvic, heart fat percentage, USDA yield grade, and marbling score. Thus, early weaning resulted in improved BW and BCS of cows as well as increased birth BW of subsequent calf, although that did not transpire into differences in postnatal growth performance or carcass traits.

Retrospective study of factors associated with bovine infectious abortion and perinatal mortality.

Abortion and perinatal mortality, leading causes of economic loss in cattle industry, are the consequence of both non-infectious and a wide range of infectious causes. However, the relative contribution of pathogens to bovine abortion and perinatal mortality is poorly documented, since available studies involved only a limited number of pathogens. Therefore, the objectives of the present monitoring study were to determine the prevalence of infectious agents associated with bovine abortion and perinatal mortality, and to identify differences in production type, gestation length, parity and seasonality by using mixed effect models (logistic regression). A pre-established sampling protocol based on the collection of the aborted fetus/calf and a corresponding maternal blood sample, involving diagnostic testing for 10 pathogens, was performed. At least one potential causal agent of the abortion or perinatal mortality was detected in 39 % of cases. In these diagnosed cases, Neospora caninum was the most detected pathogen, followed by Trueperella pyogenes, BVDv, Escherichia coli, and Aspergillus fumigatus. Neospora caninum [odds ratio (OR): 0.4; 95 % confidence interval (CI): 0.3-0.7] and Aspergillus fumigatus (OR: 0.1; 95 % CI: 0.1-0.3) were detected less in late versus early gestation. Aspergillus fumigatus was less common in dairy in comparison to beef abortion cases (OR: 0.2; 95 % CI: 0.1-0.6). Winter was associated with a lower positivity for Neospora caninum and BVDv in comparison to warmer seasons. Despite extensive diagnostic testing, an etiological diagnosis was not reached in 61 % of cases, highlighting the need for even more extensive (non-)infectious disease testing or more accurate tests.

Postpartum perineal muscle sonogram in Madura beef cow.

BACKGROUND AND AIM: Ultrasonography (USG) is useful for non-invasively identifying changes that occur in soft tissue architecture. The objective of this research was to demonstrate postpartum (PP) uterine involution through the changes of perineal muscle intensity and thickness in Madura beef cow by ultrasonography. MATERIALS AND METHODS: Madura's breed cows used in the research consist of eight non-pregnant (NP) cows and three PP cow. The transrectal and transperineal USG imaging of NP cows was performed on days 1, 33, and 65. USG imaging of PP cows was performed every day starting from day 1 (24 h after parturition) until day 21 PP. Transrectal USG of the reproductive tract was performed for the cervix, corpus uteri, and cornua uteri. USG was performed transcutaneously over the perineal area for coccygeus and levator ani muscles at the longitudinal and transverse angles. Reproductive tract diameter and perineal muscle intensity and thickness were measured with ultrasound imaging. RESULTS: The analysis of the sonogram of PP cows showed that the diameter of the cervix, corpus uteri, and cornua uteri decreased within 21 days PP. The transverse view of the coccygeus muscle of PP cows showed decreased muscle intensity and thickness. On the other hand, the longitudinal view showed increased coccygeus muscle intensity and thickness. The transverse view of the coccygeus muscle of NP cows showed increased muscle intensity, while muscle thickness was reduced. Sonogram analysis of the levator ani muscle of PP cows showed decreased muscle intensity with increasing muscle thickness. However, imaging of the levator ani muscle of NP cows showed a decrease in both intensity and muscle thickness. There was a significant difference in the mean value intensity of the scanning view analysis results of the levator ani muscle of the PP cow (523.6 AU increased to 672.1 AU) and the NP cow (515.9 AU decreased to 465.4 AU). Furthermore, there was a significant difference (p<0.05) in the mean value thickness of both scanning view analyses of the coccygeus and levator ani muscles of PP cows (5.8 mm increased to 6.5 mm and 3.8 mm increased to 4.8 mm, respectively) and NP cows (8.8 mm increased to 9.1 mm and 5.9 mm decreased to 4.9 mm, respectively). CONCLUSION: We found that the perineal muscles, namely, the levator ani muscle and coccygeus muscle, change in size, and intensity during uterine involution as demonstrated on Madura beef cow.

Assessing Extensive Semi-Arid Rangeland Beef Cow-Calf Welfare in Namibia: Part 1: Comparison Between Farm Production System's Effect on the Welfare of Beef Cows.

A proposed animal welfare assessment protocol for semi-arid rangeland-based cow-calf systems in Namibia combined 40 measures from a protocol developed for beef cattle in New Zealand with additional Namibia-specific measures. Preliminary validation of the protocol had been undertaken with five herds in one semi-commercial village. The aim of the current study was to apply this protocol and compare animal welfare across three cow-calf production systems in Namibia. A total of 2529 beef cows were evaluated during pregnancy testing in the yards of 17 commercial, 20 semi-commercial, and 18 communal (total: 55) herds followed by an assessment of farm resources and a questionnaire-guided interview. Non-parametric tests were used to evaluate the difference in the welfare scores between the production systems. The results indicated a discrepancy of animal welfare between the three farm types, with a marked separation of commercial farms from semi-commercial, and communal village farms in the least. The differences in these production systems were mainly driven by economic gains through access to better beef export market for commercial farms and semi-commercial villages, as well as by the differences in the available grazing land, facility designs/quality, and traditional customs in the village systems. The results indicate an advantage of commercialization over communalization.