The goal of health management programs for dairy cattle is to ensure the optimal care and well-being of the cows and to decrease losses in productivity caused by disease and management errors. The herd veterinarian and the dairy producer generally cooperate to develop a health management program in which the herd's actual performance on key health and production measures is regularly evaluated against predetermined targets, enabling problem areas to be identified and addressed.
The structure of dairy cattle health management programs is unique to each farm. Typically, though, these programs are keyed to the scheduled veterinary herd visits that combine routine reproductive examinations, review of selected herd performance records, and decisions and actions related to specific herd management issues.
Scheduled Farm Visits for Dairy Cattle
The frequency of scheduled veterinary visits for dairy cattle depends somewhat on herd size:
In herds of < 100 cows, one or two cows calve every week, and scheduled biweekly or monthly veterinary visits are probably appropriate. These herds might have more unscheduled visits for examination of sick cows than do herds visited more regularly.
Larger herds in which cows are calving daily warrant more frequent veterinary visits, and weekly scheduled visits are not uncommon for herds of > 200 cows.
A trend on even larger dairy farms (> 2,000 cows) is to employ a full-time staff veterinarian to oversee and direct day-to-day management of issues regarding health and performance.
The frequency of scheduled herd visits for grass-based seasonal dairy operations varies depending on the herd’s stage of lactation. More frequent visits are necessary in early lactation and during the breeding period.
Veterinary activities at herd visits fall into four general categories: provision of individual animal health care and emergency services, scheduled technical activities, scheduled analytical and training activities, and provision of quality control programs. The frequency of these activities varies.
Individual-Cow Health Care and Emergency Services for Dairy Cattle
The examination and treatment of individual cows is an important activity during scheduled veterinary visits to dairy herds. Frequent visits enable veterinarians to examine cows early in the course of disease, when the likelihood of successful treatment is higher.
Routine visits also enable veterinarians to monitor the outcome of treatments and modify treatment protocols as needed. In addition, these visits make it possible for veterinarians to work closely with farm personnel for training and information exchange.
Ideally, dairy herd monitoring programs include a system to detect cows that are not performing as expected. Special attention should be paid to the highest-risk cows, including frequent observation during the periparturient period. Cows identified as sick are treated according to predefined criteria or examined further by farm personnel or the herd veterinarian.
All treatments administered to dairy cows must be recorded in treatment logs (either computerized or handwritten) to ensure adherence to proper meat and milk drug residue withholding periods.
The frequency of unscheduled visits for emergency medical services usually diminishes in herds that adopt a health and production management program.
Scheduled Technical Activities for Dairy Cattle
Routine reproductive examinations account for much of the veterinarian’s time during scheduled dairy herd visits. Reproductive success is an essential determinant of herd productivity (see Management of Reproduction: Cattle for reproductive program details).
The goals of reproductive examinations should be to identify nonpregnant cows that can be returned to the breeding program and to generate data that can be used to determine the success or failure of breeding programs. The implementation, success, and cost-effectiveness of scheduled breeding programs should be reviewed frequently.
On smaller farms, it is often customary for the veterinarian to perform routine individual animal treatments (such as IV injections), prophylactic activities (such as vaccinations), and some technical tasks (such as dehorning calves) during scheduled herd visits. It is appropriate for the veterinarian, or a technician under the veterinarian's supervision, to perform these tasks, because the farm staff might not perform them often enough to become technically proficient.
On larger farms, farm employees should be trained to perform these tasks, because often they must be carried out daily.
Scheduled Analytical and Training Activities for Dairy Cattle
Conducting scheduled or unscheduled technical activities is not effective unless a system exists to capture the results of the activities to enable analysis and ongoing revision. The health and production management program should allocate dedicated time for the farmer and the herd veterinarian to jointly review and discuss herd management issues that affect both adult cattle and youngstock.
In herds that depend on hired personnel to implement designated tasks, time must be scheduled to effectively train and observe personnel who will be responsible for performing the activities. The development of standard operating procedures is essential to ensure that agreed-on practices are implemented.
Disease management protocols establish standardized case definitions, including clinical signs and treatment approaches, for common diseases on dairy farms. They should be developed by a herd's veterinarian together with farm personnel who work with sick cows and calves. Protocols are essential when multiple people have the responsibility to diagnose and treat cattle, especially when they are administering antimicrobials to dairy cattle or when extralabel drug dosages are prescribed.
Preventing drug residues from contaminating food products is a major responsibility of dairy practitioners. Increased scrutiny regarding antimicrobial use in food-producing animals has arisen because of concern about the development of antimicrobial resistance in foodborne pathogens.
Although the amount of detected antimicrobial residues in meat and milk products is extremely low, antimicrobial residues in bulk milk and carcasses occur occasionally. In the US, contamination of salable bulk tank milk is rare because of an effective surveillance system based on rapid testing for selected antimicrobial agents of every load of raw milk. Milk contaminated with antimicrobials is discarded, and the producer is fined.
The requirements for extralabel drug use in the US have been defined by regulatory officials under the Animal Medicinal Drug Use Clarification Act (AMDUCA) and should be closely followed. The American Association of Bovine Practitioners has responded to societal and regulatory concerns about the use of antimicrobial agents by adopting guidelines for the prudent and judicious use of antimicrobial agents in dairy cattle.
In response to concerns about the development of antimicrobial resistance in human medicine, the FDA requested that drug manufacturers eliminate the labeling and use of certain antimicrobials for production purposes (eg, to increase feed efficiency or weight gain). Specifically, antimicrobials important in human medicine are no longer permitted to be provided to food-producing animals in feed or water solely for production purposes, and no new antimicrobials will be approved for production purposes; however, they can be approved for use in feed or water for treatment or prevention of disease.
Pearls & Pitfalls
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US dairy producers who want to use an antimicrobial in feed or water must receive a feed directive from their veterinarian (essentially a prescription). Over-the-counter sales of antimicrobials for use in feed or water is no longer allowed. Also see The Veterinary Feed Directive.
Some dairy veterinarians function as nutrition specialists for the dairy farms they serve. They might collect feed samples for laboratory nutrient analysis, formulate rations, and advise farmers regarding crop and harvesting conditions and the purchase of feeds. These veterinarians often devote a considerable amount of their professional time to nutritional management.
Other dairy farms might employ a professional nutritionist or use a nutritionist employed by a feed company or local cooperative to formulate rations and submit feed samples for nutrient analysis.
Regardless of who oversees a dairy operation’s nutrition program, the veterinarian can perform an essential oversight function simply by observing body condition and general health in cows in certain high-risk situations (the periparturient period and periods of high milk production), by monitoring the incidence of nutrition-related diseases such as parturient hypocalcemia and displaced abomasum, and by ensuring that the diet described on paper is adequately formulated and delivered to the cows.
Assessing pasture conditions by periodically inspecting pasture is an important component of managing nutritional programs of herds that use management-intensive grazing.
These quality control activities should be conducted routinely as part of the health and production management program.
Quality Control Programs for Dairy Cattle
Quality control encompasses activities that ensure consistency in performing key management processes. Vital management areas for most dairy herds include nutritional management, milking management, animal welfare, sick animal diagnosis and treatment, and youngstock programs. Some farms also develop quality control processes for environment and housing and for farm-specific management of breeding bulls.
Milking management should be a standard element of quality control programs for dairy operations. Tasks such as observing the milking routine and scoring the condition of teats should be performed at least quarterly. A scheduled system of routine screening for mastitis pathogens can be implemented as part of the milking management program.
The veterinarian can teach farm personnel how to perform the California Mastitis Test (CMT) as part of a surveillance program. Animals routinely screened include cows at dry-off, fresh cows and heifers, and newly purchased cows. Any CMT-positive quarters should have milk samples submitted for culture.
Newborn calves and replacement heifers are often housed separately from lactating cows and might not be observed routinely by the herd veterinarian. However, routine surveillance of critical management issues such as adequate delivery of colostrum to calves (which can be indirectly assessed through serum total protein analysis) and growth rates of replacement heifers can be done as part of scheduled herd visits.
The environment of dairy cattle can have considerable effect on health and productivity. Some veterinarians routinely schedule “walkabouts” through the housing areas to assess factors related to animal comfort and hygiene. Udder cleanliness, hoof and hock lesions, and respiratory disease are often affected by housing conditions. Herd walkabouts should include areas often ignored, such as dry-cow and heifer housing.
Performance Targets for Dairy Cattle
Performance targets are defined benchmarks that serve as indicators of successful dairy herd management. They are useful as comparison values for herd performance and as a starting point to initiate discussions about potential areas for improvement.
For performance targets to be useful, it is necessary for a herd to have a recording system that enables the generation of comparable herd indices. In many instances, performance targets have been calculated as arithmetic averages, which are useful indicators of herd performance when the contributing data (such as milk, fat, and protein yields) are normally distributed and have a reasonable degree of variation.
The many reproductive indices and variables (such as somatic cell counts [SCCs]) that are not normally distributed rely solely on averages, which can lead to misleading conclusions about herd performance. For these types of data, evaluating frequency distributions using defined cut points (and the proportion of animals exceeding those thresholds) provides a more informative and accurate assessment.
Key performance indicators and their corresponding targets should be clearly defined. The monitoring system should specify the indices used, the animals included, and the time interval to reassess progress made toward reaching each target.
Typical performance indicators include milk production, reproductive performance, milk quality, replacement management, cow removal, animal health, and special reports (see the table Examples of Routinely Monitored Parameters in Dairy Herds).
Examples of Routinely Monitored Parameters in Dairy Herdsa
Cow Monitoring | Environment Monitoring | Records Monitoring |
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aAdapted from Noordhuizen JP. Dairy herd health and production management practice in Europe: state of the art. In: World Buiatrics Congress - Quebec, Canada, 2004. World Association for Buiatrics; 2004. https://www.ivis.org/library/wab/wbc-congress-canada-2004/dairy-herd-health-and-production-management-practice-europe | ||
Performance targets should be reviewed at appropriate intervals with realistic expectations regarding the amount of time it takes to effect change in an index. For example, management actions taken to decrease the number of days to first calving would require ≥ 9–10 months to become apparent. A more timely value, such as age at conception, would more rapidly reflect current management changes.
In addition, whereas standardized performance targets are essential for benchmarking, it is equally important to assess changes within a herd over time, rather than relying solely on comparisons with other herds or industry targets.
Recordkeeping for Dairy Cattle
A system of unique individual cow identification is a prerequisite for a successful health management program for dairy cattle. The most common methods of animal identification are ear tags, collars, and branding. Increasingly, farms are using electronic identification via transponders on ankle bands or neck straps.
At a minimum, data must be recorded for individual cows' birth, breeding, and calving dates; periodic milk yield; disease events; and removal from the herd. Under ideal circumstances, summarized data should be available for the nutritional program, disease occurrence, and financial performance.
The herd veterinarian should ensure that collected data are used in a timely manner. Accurate data collection is most likely when the producer is using the data frequently and understands their value, which can be supported through timely veterinary analysis and feedback. The validity of data generated from both manual and automated data collection systems should be reviewed and critically assessed.
Most dairy record systems can be characterized broadly as one of the following:
manual (handwritten) card systems
dairy herd improvement (DHI)–based systems with remote data storage and report generation
on-farm data collection and storage via on-farm computer systems
DHI and on-farm computer systems
Modern record systems should allow on-farm electronic access to performance data. Regardless of the type of system used, it should be easy to use and relevant to the day-to-day operations of the dairy.
Record systems on dairy farms have three important functions. The most immediate purpose is to enable herd managers to learn about individual animals and to facilitate managing those individuals. For example, a herdsman might ask why a cow's milk production is so low. What is her stage of lactation? Has she been sick? Is she pregnant? Or could she be in estrus? Does she have a history of poor production? Such information should be easily retrievable.
A second important function of dairy record systems is the generation of “action” lists (due to calve, due to dry-off, etc). This function is critical in large herds in which cattle are not individually known by the animal handlers and can be overlooked easily. As an example, timed insemination programs require up to six injections at varying intervals from 2 weeks to 2 days, and program compliance is essential for satisfactory results. Computerized herd management programs must be able to keep track of injection requirements and artificial insemination schedules for individual animals.
Finally, dairy record systems must support herd-level analysis by generating timely, actionable performance reports for important areas, including production, reproduction, and health outcomes. Some programs can also generate statistics. The recordkeeping system should enable the producer, veterinarian, and any third-party consultants (eg, nutritionists) to tailor herd analyses to answer their particular interests. Examples include reproductive performance for veterinarians or body condition scores and nutritional disease incidence for nutritionists.
For parameters and values for monitoring herd health and production, see the table Parameters Useful to Monitor Health and Production of Dairy Herds.
Parameters Useful to Monitor Health and Production of Dairy Herds
Parameter | Target |
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Adult Cow Disease | |
Average percentage of herd that is lame | < 25% |
Metritis/endometritis incidence | < 5–25% |
Subclinical ketosis (> 1.2 mmol/L) | < 10% |
Clinical ketosis | < 2% |
Left displaced abomasum | < 2% |
Milk fever | < 2% |
Retained fetal membranes | < 3% |
Cut point for ruminal acidosis | pH < 5.5 |
Clinical mastitis monthly incidence | < 3% of lactating herd |
Culling and Death Loss | |
Annual average overall cull rate | 35% |
Annual average selective cull rate | > 15% |
Annual death loss | < 10% |
Annual disease and injury culling | < 5% |
Annual reproductive cull rate | 5–10% |
Percentage removed < 60 days in milk (lactation = 1) | < 4% |
Percentage removed < 60 days in milk (lactation > 1) | < 6% |
Udder Health and Milk Quality | |
SCC farm goal (US legal limit = 750,000 cells/mL) | < 150,000 cells/mL (or adjust for a dairy) |
Standard plate count farm goal (US legal limit = 100,000 CFUs/mL) | 2,000–4,000 CFUs/mL |
Preliminary incubation count | 2,000–6,000 CFUs/mL |
Bacteria in Bulk Tank Cultures | |
Streptococcus agalactiae | 0 CFUs/mL |
Staphylococcus aureus | < 50 CFUs/mL |
Staphylococcus spp | < 1,000 CFUs/mL |
Mycoplasma spp | 0 CFUs/mL |
Environmental streptococci | < 1,000 CFUs/mL |
Coliforms | < 500 CFUs/mL |
General Reproductive Standards | |
Average days open | 100–110 (ideally lower end of range to achieve 12-month calving) |
Average gestation | 279 days |
Calving interval | 13.5 months |
Average days in milk | 150 |
Percentage of cows < 90 days in milk | 25% |
Percentage of cows 90–180 days in milk | 25% |
Voluntary waiting period (VWP) | 60–70 days for cows; 80–90 days for heifers |
Days in milk at first breeding | VWP + 11 days |
First-service conception rate | ≥ 40% |
Estrus detection | Overall, ≥ 60% (national average, < 40%) |
Intervals between breedings | 18–24 days for 65% of cows |
Length of estrous cycle | 18–24 days |
Overall conception rate | ≥ 40% |
Services per conception | 2 |
Definition of pregnancy rate (estrus detection rate × conception rate) | 21-day interval |
First-cycle pregnancy rate | > 30% |
Percentage pregnant by three cycles | > 50% |
Overall pregnancy rate | > 25% |
Percentage of herd pregnant by 150 days in milk | > 75% |
Pregnancy Diagnosis | |
When to do pregnancy checks | 28–32 days after being bred |
Ability to locate amnion | 35–65 days |
Membrane slip | Day 30 to term |
Ability to locate fetus | 65–95 days |
Placentomes present | After 3 months of gestation |
Ability to sex fetus | After 60–70 days of gestation |
Pregnancy stage estimation by amnion size: | |
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Pregnancy stage estimation by fetal crown-to-nose length: | |
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Postpartum Involution | |
Lochia (normal): | |
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Entire uterus palpable | 2 weeks |
Full decrease in size | 40–45 days |
Epithelialization complete | 40–45 days |
Occurrence of endometritis | > 26 days after calving |
Full uterine involution | 40–45 days post partum |
Abortion | |
Normal embryonic loss (< 50 days) | < 10% |
Average rate of early embryonic loss | 15% |
Normal rate of abortion | 3% |
Major infectious abortion agents | Bovine viral diarrhea, mycotic, leptospirosis, Neospora |
Youngstock | |
Transfer of passive immunity | Excellent: ≥ 40% (> 6.1 g/dL) Good: approx. 30% (5.8–6.1 g/dL) Fair: approx. 20% (5.1–5.7 g/dL) Poor: < 10% (< 5.1 g/dL) |
Preweaning respiratory disease morbidity rate | < 15% |
Preweaning mortality rate | < 3% |
Lung consolidation (≥ 3 cm2) at weaning | < 15% |
Average daily weight gain | ≥ 800 g |
Abbreviations: SCC, somatic cell count; VWP, voluntary waiting period. | |
Unusual results and deviations from normal dairy cow performance targets should be challenged. The producer and the veterinarian should agree on defined actions based on the herd status and goals. Actions are generally oriented toward diagnosis, prevention, or treatment.
Investigation of Health and Production Problems of Dairy Cattle
Even on the best-managed farms, unexpected health and production problems arise. Surveillance programs incorporated into health and production management programs should detect problems early, before considerable financial damage has occurred.
Systems to investigate herd disease outbreaks have been described. Epidemiological concepts of disease investigation are useful to identify risk factors and to stimulate corrective action.
For More Information
Lombard J, Urie N, Garry F, et al. Consensus recommendations on calf- and herd-level passive immunity in dairy calves in the United States. J Dairy Sci. 2020;103(8):7611-7624.
Wean Clean. The Dairyland Initiative.
NMC Resources. NMC: The Global Milk Quality Organization.
NAHMS [National Animal Health Monitoring System] Dairy Studies. Animal and Plant Health Inspection Service, USDA.
Calf Care & Quality Assurance (CCQA) Animal Care Reference Manual. Farmers Assuring Responsible Management (FARM).
