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Passive immunity in calves is evaluated or quantified by measuring serum or plasma IgG or serum total protein within the first 7 d of age. While these measurements inform about circulating concentrations of this important protein, they are also a proxy for evaluating all of the additional benefits of colostral ingestion. The current individual calf standard for categorizing dairy calves with successful passive transfer or failure of passive transfer of immunity are based on serum IgG concentrations of ≥10 and <10 g/L, respectively. This cutoff was based on higher mortality rates in calves with serum IgG <10 g/L. Mortality rates have decreased since 1991, but the percentage of calves with morbidity events has not changed over the same time period. Almost 90% of calves sampled in the USDA National Animal Health Monitoring System's Dairy 2014 study had successful passive immunity based on the dichotomous standard. Based on these observations, a group of calf experts were assembled to evaluate current data and determine if changes to the passive immunity stan-dards were necessary to reduce morbidity and possibly mortality. In addition to the USDA National Animal Health Monitoring System's Dairy 2014 study, other peer-reviewed publications and personal experience were used to identify and evaluate potential standards. Four options were evaluated based on the observed statistical differences between categories. The proposed standard includes 4 serum IgG categories: excellent, good, fair, and poor with serum IgG levels of ≥25.0, 18.0-24.9, 10.0-17.9, and <10 g/L, respectively. At the herd level, we propose an achievable standard of >40, 30, 20, and <10% of calves in the excellent, good, fair, and poor categories, respectively. Because serum IgG concentrations are not practical for on-farm implementation, we provide corresponding serum total protein and %Brix values for use on farm. With one-third of heifer calves in 2014 already meeting the goal of ≥25 g/L serum IgG at 24 h of life, this achievable standard will require more refinement of colostrum management programs on many dairy farms. Implementation of the proposed standard should further reduce the risk of both mortality and morbidity in preweaned dairy calves, improving overall calf health and welfare.

The objectives of this observational study were to use time-lapse video photography to document dairy cow behavioral patterns, examine factors affecting lying behavior, and to develop guidelines for visual assessment of free-stall usage during summer conditions in a high producing dairy. Four video cameras were placed in a free-stall pen containing 144 stalls and 129 high producing cows. The videos were recorded over a 6-d period in July 1999 and then were reviewed using 60-min scan sampling techniques. Cows were counted as lying, standing in alley without eating, standing in free stalls, or eating in each of the four sections of the pen. Temperature probes were placed on the feedline, free stalls, on both ends of the pen, and at an outside location. Relationships between proportion eligible lying and ambient temperature, feeding time, and time since milking were examined. Proportion eligible lying was equal to number of cows lying divided by total number of cows lying or standing but not eating. Cattle showed a significant pattern of temporal cyclicity in their lying behavior, with the highest average proportion of eligible cows lying at 6:00 a.m. (85%) and the lowest at 9:00 p.m. (53%). Increasing environmental temperatures and time elapsed since milking negatively impacted proportion of eligible cows observed lying when evaluated using 60-min scan sampling techniques.

BackgroundAdipose tissue is an active endocrine organ which secretes a wide range of hormones and protein factors, collectively termed adipokines. Adipokines affect appetite and satiety, glucose and lipid metabolism, inflammation and immune functions. The objectives were to evaluate serum concentrations of adipokines (adiponectin, leptin, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6) in lactating dairy cows with postpartum uterine inflammatory conditions (metritis, clinical endometritis or subclinical endometritis) and in cows experiencing loss of body condition, and to assess the relationship of adipokines and body condition loss in the establishment of persistent uterine inflammatory conditions.MethodsLactating multiparous Holstein cows (N = 40), with body condition scores (BCS) from 2 to 4 (eight cows for each 0.5 score increment) were enrolled. Body condition was monitored for all cows weekly for 7 weeks post calving; cows with uterine inflammatory conditions were also re-evaluated 2 weeks later. Blood samples were collected from 1 week prior to calving to 7 weeks after calving for determination of serum concentrations of adipokines, insulin and insulin like growth factor (IGF)-1.ResultsCows with metritis or clinical endometritis had higher serum concentrations of adiponectin, leptin, TNF-alpha, IL-1beta and IL-6 compared to normal cows (P < 0.05). Furthermore, serum leptin, TNF-alpha, IL-1beta and IL-6 were higher in cows with subclinical endometritis compared to normal cows (P < 0.05), and insulin and IGF-1 concentrations were lower in cows with metritis or clinical endometritis. Cows with low BCS (2 and 2.5) had significantly higher adiponectin, TNF-alpha, IL-1beta and IL-6 than those with high BCS (3 to 4). Cows with persistent uterine inflammatory conditions had higher adiponectin, leptin TNF-alpha, IL-1beta and IL-6 and insulin compared to normal and spontaneously recovered cows, except for IGF-1 (P < 0.05).ConclusionsSerum concentrations of adipokines, insulin, and IGF-1 had significant associations with BCS categories (low vs. high) and postpartum uterine inflammatory conditions. Perhaps loss of body condition mediated increases in anti- and pro-inflammatory cytokines, whereas increased pro- and anti-inflammatory cytokines concentrations mediated body condition loss and thereby prolonged persistence of uterine inflammation in dairy cows.

The objective of this study was to describe the influence of in-feed and therapeutic antimicrobials on resistance in commensal fecal Escherichia coli isolated from preweaned calves. Four groups of 30, day-old calf-ranch calves were enrolled and raised until 4 weeks of age. Groups 1 to 3 were raised without antimicrobials in the feed. Group 1 was isolated from the other groups and received no antimicrobial therapy. Group 2 was housed on the calf ranch and did not receive antimicrobial therapy, whereas groups 3 and 4 could be treated with antimicrobials. Group 4 was fed neomycin and tetracycline HCl in the milk replacer. Fecal samples were collected from calves on days 1, 14, and 28. Three E. coli isolates per sample were evaluated for susceptibility to 12 antimicrobials. Cluster analysis was used to group isolates having similar susceptibility patterns. Cumulative logistic regression was used to evaluate factors associated with increasing levels of multiple antimicrobial resistance. In-feed antimicrobials were associated with higher levels of multiple antimicrobial resistance in fecal E. coli.f In calves not receiving in-feed antimicrobials, older calves had higher levels of resistance compared to day-old calves. Individual antimicrobial therapy increased resistance in these calves but appeared to be transient. There was no environmental influence on resistance in E. coli populations among study groups.Although antimicrobials are used in calf rearing to treat and prevent disease, their use is increasingly viewed as a factor in the emergence of bacterial antimicrobial resistance in animal and human pathogens (13,15,16). Bull calves destined for beef are often raised on dedicated calf ranches in the United States. In these systems, calves are brought onto the ranch as day-olds and individually housed in hutches until they are weaned between 50 and 70 days of age. The challenge to management is that assembling large numbers of calves from multiple sources can create a highly susceptible population to infectious disease. To counteract this, antimicrobials such as tetracycline and neomycin are often incorporated into the milk replacer to prevent disease and raise healthy calves (8,21,24). The practice of adding antimicrobials into feed (milk or grain) creates a selection pressure for antimicrobial-resistant bacteria that could affect human health, but data associating antimicrobial resistance with prophylactic and metaphylactic antimicrobial use in animals are limited (23).Multiple studies have shown that the young, preweaned calf harbors a multiply resistant commensal Escherichia coli enteric flora (17,20,25,27). A recent study of commensal E. coli isolated from preweaned calves on calf ranches and dairies described the many factors associated with antimicrobial resistance in these organisms (4, 5). The central finding was that multiple-resistant fecal E. coli were predominant in preweaned calves regardless of antimicrobial exposure. Farm type (calf ranch versus dairy) and individual antimicrobial therapy were both a...

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Nonsaleable whole milk from dairy farms is potentially an economical, nutritious source of feed for neonatal calves but it can have serious quality problems. Many calf-rearing operations that utilize this milk have no system in place to assess or manage quality problems other than pasteurization. The purpose of this investigation was to evaluate the quality of nonsaleable whole milk from dairy farms being used to feed neonatal calves using a set of standard milk quality monitors. In this study, nonsaleable whole milk samples from 12 dairies supplying both milk and calves to one calf ranch were collected and evaluated for total solids (TS) percentage, bacterial counts, coagulation with ethanol, somatic cell counts, and pH. Milk quality was not uniform among the farms. Bacterial counts provided relatively little useful information to assess milk quality, because most samples (9/12) had very high bacteria counts. The most variable quality finding was TS percentage. Many samples were low in TS, contributing to a low TS percentage in pooled milk being fed to calves, which created a poor nutritional product delivered to them. Although there are advantages to feeding nonsaleable whole milk to preweaned calves, there can be significant disadvantages if the quality of the product is poor. Microbial quality is an important aspect of milk, but most of the samples were highly contaminated and the need for pasteurization was assumed. Simpler and more immediate monitoring methods such as milk pH, the alcohol test, and TS could be used at the ranch to make decisions on whether to use the milk. On the study ranch, a program to evaluate the TS of nonsaleable whole milk was implemented and a chart to add solids was devised for the producer so that the neonatal calves would not be underfed nutrients. Implementing these measures will help improve the health and growth of young calves.

Interventions, such as dog bite prevention education, vaccination of pets against rabies, appropriate use of PEP, and reduction of feral cat populations, should be instituted, enhanced, or better enforced in communities.