About Biosecurity_Cattle

What is biosecurity?

Biosecurity at a cattle farm includes all measures taken to minimize the risk of introduction and spread of disease agents and thus, includes all actions for keeping the animals and the farm healthy. By taking these biosecurity measures and performing efficient management, on-farm animals are protected against both endemic and epidemic diseases (Barceló and Marco, 1998; Amass and Clark, 1999; Damiaans et al., 2018).

A distinction is made between external and internal biosecurity. 

External biosecurity focuses on the contact points of the farm with the outside world and aims to prevent that pathogens can enter or leave the farm. This applies both to exotic diseases, which occur rarely in a country, as well as to endemic diseases, which are common in a country but do not occur at every farm (Ribbens et al., 2008). All measures taken to counteract the spread of infectious agents within a farm are covered by internal biosecurity (Laanen et al., 2010; Anonymous, 2010).

Why biosecurity?

The main objective of biosecurity is to keep the infection pressure at the farm as low as possible. This way, the immune system of a certain animal will be less stressed, resulting in a lower risk of a disease outbreak and, consequently, better animal health and welfare.

By reducing the potential risks for a disease outbreak with the implementation of biosecurity measures, other favourable consequences may also be established for the farm. For example, in several studies with pigs, biosecurity showed a positive association with the production results (such as daily growth) and the profitability of the farm. Along with this, the use of antibiotics can be greatly reduced (Laanen et al., 2011; Siekkinen et al., 2012; Laanen et al., 2013; Postma, 2016a; Postma et al., 2016b; Postma et al., 2016c, Postma et al., 2016d). In addition, decreasing the use of antibiotics within animal production will reduce antibiotic resistance and this is good for both animal and human health (Angulo F.J., 2004; Chantziaras et al., 2014).

Disease transmission routes

Regarding disease transmission, not all transmission routes are of equal importance. Therefore, it is not easy to rank the different routes according to their relevance. This is mainly due to the large variation among the infectious agents in their ability to infect a living creature, such as their survival chances in the environment. So it is clear that not all biosecurity measures will contribute in the same way to the prevention of different infectious diseases (Dewulf and Van Immerseel, 2018).

Direct contact between animals is considered to be the main transmission route of infectious agents. Therefore, more attention will be paid to biosecurity measures which avoid direct contact between animals than to measures taken to prevent indirect transmission through, for example, work material or persons (Amass, 2003a; Pritchard et al., 2005; Amass and Baysinger, 2006).

An additional but still important factor is the frequency to which a pathogen can infect an animal population along a specific pathway. A less crucial transmission route may become very important the moment it creates an entrance for pathogens at the farm multiple times (Fèvre et al., 2006; Laanen et al., 2013).

The combined risk (chance of transmission x frequency) can be calculated using the following formula:

P = 1-(1-p)ⁿ

with p = the risk of disease transmission per event, n = the number of events and P = the combined risk (probability).

Example

If you assume that a certain transmission route has only one chance at 1000 (= 0.1%) to effectively transmit the disease and if you also know that this route occurs 50 times a year (e.g. weekly activity), the chance of disease transmission at the end of the year will be 1 - [(1 - 0.001)⁵⁰] = 4.88 % (Dewulf, 2017).

On the other hand, the risk of disease transmission through a specific transmission route, which has a chance of 1 to 50 (= 2%) to transmit the disease, but which occurs only twice a year will be 1 - [(1 - 0.02)²] = 3.96%.

(Laanen et al., 2010)

Therefore, you should be well aware of the fact that any transmission pathway, also the less important ones, may pose a risk to the introduction and spread of infectious disease. In this way, vigilance on all biosecurity levels will always be very important for the farm.

The figure below illustrates the relative importance of the different pathways of pathogen transmission between farms (Laanen et al., 2010).

External biosecurity

Purchase and reproduction

Disease transmission between animals

The introduction of new cattle through purchase is the most cited risk factor for introduction of disease pathogens in a herd (Valle et al., 1999; Boelaert, 2005; Cuttance & Cuttance, 2014). Although the risk of introducing pathogens depends on the frequency of purchase and type of purchased animals (e.g. young stock, breeding bull, pregnant heifers, lactating cows), every introduction of new cattle poses a risk of entering disease into a herd. Therefore, the general advice is to avoid purchase of cattle as much as possible. However, for some reasons it is possible that cattle have to be purchased. E.g. a breeding bull may be needed when the conception rate through artificial insemination is too low, or some female young stock could exceptionally be added to the herd when too many male calves were born. 



Whenever the purchase of cattle is necessary, measures to avoid disease transmission through direct and indirect contact should be applied. As veal farms cannot avoid purchase, these measures should be considered even more important.

When cattle is transported to the farm, contact with cattle (or other animals) from an unknown disease status, should be avoided (Mee et al., 2012). Ideally, only the cattle destined for your farm should be present on the transport vehicle. When using your own transport vehicle, you also know the cleaning and disinfection status of the vehicle.

Production cycle

Veal calf farms are a special case, as they typically purchase all their animals, which originate from many different farms. Nevertheless, the number of purchases are highly important. Therefore, production cycles should not be shorter than 6 months, and preferably longer than 9 months. At the start of a production cycle, each compartment should be filled in as short a period as possible so the age difference of the animals in direct contact with each other is as low as possible, never exceeding two weeks.

Source herds with a high health status

The risk of disease introduction can be reduced by purchasing cattle from farms with a sanitary status and health management that is equal or higher than your own farm (Griffin et al., 2010; Sweiger & Nichols, 2010). When your farm has a Specific Pathogen Free (SPF) health status for a disease (e.g. infectious bovine rhinotracheitis or bovine viral diarrhoea), it is advised to purchase cattle from farms with the same or a higher health status. Furthermore, farmers who want to obtain an SPF-status for some diseases are more likely to have a good health management in general and by consequence less occurrence of other diseases. Also when purchasing semen, embryos or colostrum, attention should be paid to the health status of the farm/institution of origin.

Limit the number of source herds

Limiting the number of farms of origin where cattle are purchased, can reduce the risk of disease introduction (Edwards, 2010; Mee et al., 2012). Cattle should always be purchased from the initial farm of origin. In particular, for veal calves farms, this can pose a problem, since the animals originate from many different farms. In such cases, calves could be divided into smaller risk groups, depending on one or more specific disease statuses (Pardon, 2012).

Animal entry protocol

Even when cattle is purchased from farms with a sanitary status and health management that is equal or higher than your own farm, the individual disease status of the purchased cattle should be checked by testing the animals, preferably at the farm of origin (Gorden & Plummer, 2010). This way you avoid that diseased animals enter the farm and whenever a test result would be positive, the purchase is cancelled. One should realize that the animals can be carriers of other disease agents (e.g. Mortellaro disease, Psoroptes ovis mange, Staphylococcus aureus mastitis, Q-fever) than those few tested for. Testing a milk sample of lactating cattle and checking maternal immunity in calves under 4 months old, is advised.

Respect a good quarantine

Once purchased cattle arrive on the farm, they should be quarantined, i.e. the animals are placed in isolation without contact with the own herd for a sufficiently long period of at least 21 days (Maunsell & Donovan, 2009; Gorden & Plummer, 2010; Raaperi et al., 2014). It has to be pointed out that quarantining purchased cattle cannot be replaced with only testing of those animals, as they can be carriers of other disease agents than those few tested for (see above). Quarantine allows the newly introduced animals to adapt to the farm (e.g. feed, climate) and avoids that purchased cattle can transmit disease to the herd. The recommended isolation period length varies, depending on the disease. But for diseases with a short incubation period preferably three to four weeks is advised (Wells et al., 2002; Barrington et al., 2002; Callan & Garry, 2002; Villarroel et al., 2007; Maunsell & Donovan, 2008). An appropriate quarantine area is a space that prevents disease transmission through direct contact, but also indirect contact (e.g. aerosols). Therefore, a quarantine area is preferably a separate building where no other animals are present (Edwards, 2010). A pasture or an old premise can also serve as quarantine area. Furthermore, one should also take into account that:

-A quarantine period of three to four weeks is insufficient for diseases with a long incubation period, e.g. Mycobacterium avium subspecies paratuberculosis (Johne's disease);

-When purchasing cattle in lactation, those cattle preferably are milked inside the quarantine area to avoid alien pathogens entering the milking parlor

-When purchasing pregnant cattle, calving preferably occurs in the quarantine area and the new-born is tested immediately after birth (before the intake of colostrum) and should be quarantined until test results are available;

-The all-in/all-out principle should be applied for animals in quarantine. The quarantine stable should be completely empty after removal of the animals, leaving room to clean and disinfect the stable.

Indirect disease transmission from cattle in quarantine is possible through people entering the quarantine area, the material that is used and the feed and water that are provided to the cattle. Specific clothing and boots (and/or a disinfection footbath) should be available at the entrance of the quarantine area, and can only be used for this purpose. Everyone who enters the quarantine area should make use of these facilities. Preferably hands are washed when entering and leaving the quarantine area (Edwards, 2010). Moreover, in the daily routine, farmers are advised to enter the quarantine area only at the end of their working scheme. Specific material (e.g. feeding utensils) should be available in the quarantine area and cannot be used in the own herd. Feed that is present in the quarantine area should not be used to feed the own herd (Edwards, 2010; Gorden & Plummer, 2010).

Sometimes cattle leave the farm but come back afterwards, e.g. a breeding bull shared with other farms or for auctions, contests or markets. Such animals should also be quarantined when they return to the farm according to the same principles as mentioned above (Gorden & Plummer, 2010).

Disease transmission by genetic material

Venereal transmission is a risk in all reproductive activities, natural insemination by one or more breeding bulls, and also artificial insemination. In order to control these risks as good as possible, the semen of bulls used for breeding, should be tested for venereal diseases before reproduction. In case the semen is imported, it should be imported from an institution with a health status equal to or higher than that of the own farm.

Transport and carcass removal

Cattle transport and disease transmission

Although animal movements are generally considered as the major cause of disease spread, (professional) visitors and vehicles entering the farm should also be considered when establishing a biosecurity strategy for the farm (Alvarez et al., 2011). The risk of disease transmission depends among other things on the type of vehicle: for instance, rendering company trucks are considered a higher biosecurity risk than feeding company trucks (Ribbens et al., 2009). Therefore, the carcass storage should be located close to the public road to avoid the truck of the rendering company to enter the premises. Although feed and milk collection trucks rarely come in contact with the animals on a farm (Nöremark et al., 2013), these vehicles should be considered as a biosecurity risk as they visit several herds on the same day (Ribbens et al., 2009). Therefore, all vehicles entering the farm should pass through a disinfection bath.

Cattle stables are designed in such a way that tractors can easily enter the premises to feed the animals and clean the pens. However, this means that vehicles from professional visitors can also enter the stables. By doing so, these vehicles come close to the animals and visitors will less likely take the route that is passing through the sanitary transition zone. Therefore, it is recommended that vehicles do not enter the stables and parking space is provided close to the sanitary transition zone. Feed should be delivered and tank milk collected without the need for the driver to enter the stables.

When cattle leaves the farm, the animal transportation truck is preferably empty, cleaned and disinfected upon arrival at the farm (Crookshank et al., 1979). However, often cattle from other farms are already present on the truck. Therefore, farmers are recommended not to enter the truck when loading animals to avoid contact with cattle from other farms. Above that, the transporter should not be allowed to enter the stables to avoid contact with the animals on the farm. Furthermore, cattle that leaves the farm can be moved to a separate building or loading area. E.g. male dairy calves that are sold at young age can be housed at a different location than the female calves that remain on the farm.

When equipment is shared with other farms, such as a transportation vehicle or manure spreader, the equipment must be cleaned and disinfected before returning to the farm (Brennan et al., 2008).

Cadavers and disease transmission

For every dead animal the cause of death may be infectious and therefore dead animals should be removed from the farm as quickly as possible to avoid disease transmission through direct and indirect contact.

Until the carcasses are collected by the rendering company they should be stored in a separate storage space with at least a cemented floor (Smart et al., 1982). Preferably this storage space is located close to the public road to avoid trucks of the rendering company from entering the farm.

When carcasses are manipulated, the use of disposable gloves and/or cleaning and disinfection of the hands and all material used for the manipulation afterwards is recommended. Furthermore, cleaning and disinfection of the carcass storage place after each use is advised. To avoid disease transmission through rodents, cats and dogs the storage place should be sealed off. Ideally, waste water must be collected in a well.

Feed and water

Feed and disease transmission

Contamination of feed with pathogens and/or (myco)toxins can occur at all stages of feed production and storage. Crops can be contaminated with manure during fertilization of the crops or neighbouring pastures. Therefore, attention should be paid when manure from other farms is used close to own crops or pastures. Furthermore, excretions and secretions of carrier animals may contaminate feed (Maciorowski et al., 2007). All feeding utensils should be cleaned after each use to remove remnants as a possible source of contamination. To avoid the growth of pathogens and/or production of myco(toxins), good procedures of handling and storing feed should be respected, e.g. by adding products for a better preservation of the silage pH.

Water and disease transmission

Contamination of water can occur at the water source, in a reservoir or in the pipes and at the outlets. It is therefore recommended to test preferably twice a year the water quality by bacteriological and chemical analysis at each of these places. Furthermore, the water troughs should be checked and cleaned regularly to avoid contamination with faeces, urine and feed. For this reason, water troughs are preferably placed somewhat higher and far from feeding troughs (Wright, 2007).

To avoid contamination of feed and water by rodents, birds, dogs and cats, access to the food storage facility and water reservoirs should be limited as much as possible.

Visitors and farmworkers

Disease transmission between humans and animals

Cattle farms are very often visited by professionals (Nöremark et al., 2013; Sarrazin et al., 2014). Professional visitors enter farms for work-related reasons and may hereby come into close contact with cattle. Besides veterinarians, other professional visitors are for instance the artificial insemination (AI) technician, the cattle salesman, the feed supplier, the milk collector, the rendering company, the hoof trimmer and possibly also other caretakers (personnel).

Very often (professional) visitors can freely enter the farm and stables where cattle are housed (Sarrazin et al., 2014). Nevertheless, it is recommended that every visitor can only enter the farm after notifying the farmer, and the stables should only be entered together with the farmer. Fencing the farm and closing the entrance with a gate, making the phone number of the farmer visible and restricted area signs (pictograms), are practical tips that make visitors aware that they should not freely enter the farm and stables.

Hygienic measures

Other adequate biosecurity measures for professional visitors are the use of herd-specific protective clothing and boots, well-maintained disinfection footbaths and washing hands/wearing gloves before entering the stable (Villarroel et al., 2007; Nöremark et al., 2013). These basic biosecurity measures should be very accessible for all visitors, since it was noticed that although these measures were present in the majority of the cattle farms, they were rarely used (Sarrazin et al., 2014). Furthermore, it has to be pointed out that not only veterinarians but every (professional) visitor can represent a source of indirect transmission. In a recent study it was noticed that biosecurity measures at the farm entrance were not implemented by all visitors in the same extent: veterinarians used protective clothing and boots more often than AI technicians, followed by cattle salesmen (Sarrazin et al., 2014). A sanitary transition zone where visitors can change clothes and wash their hands should be accessible with a minimum of efforts so one has to first access the sanitary transition zone and the stables afterwards.

All traffic in and out of the stables constitutes a risk for disease spread by indirect contact, including employees’ entrance. Therefore, it is advised that employees should not visit other farms and the same measures as described above should be applied by all members of the farm’s staff entering the stables.

Vermin control and other animals

Disease transmission between animals

Very often direct contact is possible between the own animals and cattle from other farms, through an adjacent pasture or a common passage, constituting a high risk for disease transmission. Furthermore, disease transmission between cattle from different farms is possible when they have access to the same surface water in the pastures. The general rule should therefore be to avoid contact on the same or adjacent pastures. Whenever this is not possible, double fenced pastures may reduce the risk of disease transmission (Valle et al., 1999; Nafstad & Gronstol, 2001; Raaperi et al., 2014). These risks exist as well for contact with other species (sheep, goats, pigs, poultry,…) and other herds of cattle on the same farm (e.g. possible contact between beef cattle and veal calves on the same farm). However, for a disease that is not transmitted through air such as bovine viral diarrhoea (BVD), a distance of at least 3 meters is recommended (Laureyns et al., 2010). Another recommendation is to pasture high risk groups (i.e. infection of those animals may have huge consequences, e.g. abortion of animals in gestation) on land with no adjacent pastures. Indirectly, crops can be contaminated with manure during fertilization of the crops or neighbouring pastures. Therefore, attention should be paid when manure from other farms is used close to own crops or pastures. Furthermore, excretions and secretions of carrier animals may contaminate feed (Maciorowski et al., 2007).

Control measures

The presence of rodents, insects, wild birds and stray cats is difficult to avoid on cattle farms. Also domestic cats and dogs are very often present. To avoid disease transmission through these animals (e.g. neosporosis, leptospirosis), their access to the stables, manure storage facility and feed storage facility should be limited as much as possible by closing or shielding doors, windows and gates and placing traps (Synge et al., 2003; Fossler et al., 2005; Nielsen et al., 2007). Moreover, cats are not considered a good rodent control program. Traps and/or poison are recommended to control vermin.

Internal biosecurity

Health management

Sick animals

A hospital pen is a space where sick animals are housed to prevent disease transmission towards other animals in the herd through direct and indirect contact (e.g. aerosols!) (Gorden & Plummer, 2010; Maunsell et al., 2011). A hospital pen should never be used as maternity pen and vice versa (Fossler et al., 2005). After each use the hospital pen should be empty in order to be thoroughly cleaned and disinfected (Edwards, 2010).

When lactating cattle is diseased, it is advised that they are milked in the hospital pen or, whenever this is not possible, as the last animal in the regular milking facility to avoid contact with the healthy animals (Hage et al., 2003; Fossler et al., 2005). In case of the latter option, special attention should be paid to the cleaning and disinfection of milking material that is also used for healthy animals.

Chronically infected animals (e.g. paratuberculosis, bovine viral diarrhoea virus persistently infected animals, chronic subclinical mastitis, …) are a continuous source of infection and produce suboptimal. Therefore they should be removed from the farm. Such animals are often kept in the herd or in isolation until the moment of slaughter, but this practice should be discouraged because of the high risk of disease transmission through direct and indirect contact.

Measures between compartments

Similarly as entering the quarantine area at the end of the daily working scheme, diseased animals should be taken care of after the healthy animals (Maunsell et al., 2011). The same biosecurity measures to avoid indirect disease transmission in the quarantine area, apply to the hospital pen: the use of specific clothing, washing the hands before and after contact with diseased animals and specific material only to be used in the hospital pen, are strongly recommended.

If multiple animals in the same group are diseased, it might be a better choice to isolate the unit and take measures such as providing boots and clothing specific for the unit, instead of moving several animals separately to the hospital pen.

Animal health register

A register with animal health data is strongly advised, so an overview of the health and treatment status of individual animals and groups is present (Edwards, 2010; Pardon et al., 2012). Such a register can contain the following information:

-Which animals are currently under treatment and which treatment do they receive?

-Which animals are sick on a regular basis?

-What are the vaccination protocols for the different diseases and which (groups of) animals have to be vaccinated?

-For cattle that go on pasture: when do they have to be rotated (every 2 to 6 weeks) or treated against endoparasites and ectoparasites?

-When do cows have to go through a disinfection footbath?

-How is the udder health of lactating cows?

Calving management

The period around calving is known to be a very critical period for the dam, which experiences a temporary decrease in immunity, and for the new-born calf, which is born without acquired immunity. Therefore, much attention should be paid to the calving management to avoid disease transmission through direct and indirect contact (Klein-Jöbstl et al., 2014).

Maternity pen

A maternity pen is a space where the dam is housed shortly before and after calving and is never used to house sick animals. In the maternity pen there should be no contact with other cattle, although visible contact may be recommended to avoid stress (Svensson et al., 2003). Before and after each calving, the maternity pen should be cleaned and disinfected (Gorden & Plummer, 2010). Therefore, after each calving, the maternity pen should be empty. The use of specific clothing and boots, washing of the hands before and after contact with the animals and specific material only to be used in the maternity pen should be applied, similarly to the quarantine area and the hospital pen.

When calves cannot be born through natural calving, a caesarean section has to be performed by the veterinarian. For this type of calving, similar biosecurity measures apply: a separate, clean and disinfected space without contact with other cattle and the use of herd-specific clothing by the veterinarian.

Hygiene during calving

It is recommended that the farmer is always present at the moment of calving. Hands, together with all obstetric material, should be cleaned and disinfected before and after each calving. Before a natural calving the dam is prepared by cleaning and disinfecting the udder and vulva (Meganck et al., 2015). After calving, the foetal membranes and tissues are removed from the calving area and attention has to be paid that especially dogs do not eat these membranes and tissues (Anderson et al., 2000; Wouda, 2000).

Immediately after birth the navel of the calf is dipped with a fresh disinfectant in a clean vessel. A disinfecting spray can also be used, but one has to be sure that the entire navel is sprayed and only manipulated with clean and disinfected hands (Mee, 2008; Gorden & Plummer, 2010). Except for suckling calves, new-born calves should be removed from the dam within one hour after birth (Maunsell et al., 2011; Gorden & Plummer, 2010).

A dam that has aborted, should be considered as a sick animal and therefore housed in the hospital pen until the reason for abortion has been determined.

Calf management

Colostrum

Since calves are born without acquired immunity, the ingestion of sufficient maternal antibodies through colostrum within the first hours of life is crucial (Harp & Goff, 1998; Mohammed, 1999). The administration of colostrum should fulfil the following requirements:

-A sufficient amount of colostrum has to be administered, i.e. 300 grams IgG antibodies (Lombard et al., 2020). The concentration of IgG antibodies in the colostrum can be verified in several ways and depends among other things on the age and type of cattle. Given the amount of milk that dairy cattle produce, the concentration of maternal antibodies is lower, and therefore more colostrum has to be given in comparison to beef cattle.

-The best quality colostrum is obtained from the first milking. The mother’s colostrum is preferred over that of other cows and fresh colostrum is preferred over frozen colostrum. Frozen colostrum should never be thawed in a microwave oven but instead in warm water of 40-45°C as antibodies are destroyed above 50°C. Using colostrum from other farms is not advised given the fact that the maternal antibodies in the colostrum of the dam or other cows present in the herd reflect the herd immunity better than colostrum from other farms. Above that, there is the possibility of transmission of pathogens through colostrum (e.g. paratuberculosis).

-The absorption of antibodies through the gut quickly drops in calves. Therefore, the required amount of colostrum should be administered within 6 hours after birth (Gulliksen et al., 2009).

-Given the small capacity of the abomasum, colostrum should be administered frequently to avoid flow into the undeveloped rumen. Therefore, not all colostrum can be given at once, but should be spread over more feedings (Gorden & Plummer, 2010). Between feedings, colostrum should not be left in the stable but cooled in the refrigerator.

-Materials used, such as bottles and tubes for colostrum administration, should be cleaned and disinfected after each use.

Housing of the calves

During the first weeks of their life, calves are preferably housed in individual calf boxes or hutches without physical, but with visible contact with other calves (Klein-Jöbstl et al., 2014). Hutches should be draught-free and placed on a paved/cemented and easy to clean surface (Lundborg et al., 2005). Attention should be paid that urine and faeces cannot be spread from one hutch to another.

When calves leave their individual housing, regrouping to pens of 7-10 calves of the same age is advised. Both group housing and individual hutches should be well cleaned, disinfected and dry before new animals enter. In group housing, different groups should not be able to have contact with other groups.

Feeding the calves

Calves should receive milk in their own and always in the same bucket. This can easily be done by numbering the boxes/hutches and buckets. After each feeding, the buckets are cleaned and placed upside down until the next use to avoid dust, water, flies… getting into the buckets (Lassen et al., 2009; Meganck et al., 2015). Feeding of calves with milk from cows under antimicrobial treatment is strongly discouraged (Virtala et al., 1999).

Dairy management

Maintenance of equipment

An optimal milking management starts with well-functioning milking equipment. A yearly maintenance and control of the milking equipment should be performed by a static (without milking cows) and dynamic (while milking cows) test. A dynamic test evaluates the milking process by the machine and farmer and therefore only by this test a complete overview of the well-functioning of the milking process is obtained. The frequency of replacing teat cup liners depends on the type: rubber and silicone teat cup liners should be replaced after 2500 and 10 000 milkings, respectively.

Milking technique

An optimal milking technique is a next crucial factor in the milking management. The following recommendations more specifically apply to manually milking, but in general also apply to robot milking:

-The farmer should wash, clean and disinfect the hands before milking and/or use gloves

-Teats should be cleaned drily before milking with a clean cloth. When teats are also disinfected before milking, teats should be dried after disinfection. Teats should be disinfected after removing the teat cups

-Foremilk should be examined visually

-The milking equipment and parlour should be cleaned after milking

-Between cows the milking equipment should be disinfected, preferably with steam or water over 75°C.

Milking management

Cows should be milked in optimal conditions by optimising comfort and hygiene:

-The flanks, udders and tails should be clipped

-To avoid stress, the hierarchical order among the cows should be respected, but still keeping in mind that sick cows in lactation (e.g. mastitis) are preferably milked last

-After milking, the teat openings remain open for about 30 to 60 min. It is therefore advised to keep the cows standing after milking for at least 30 min. This can be facilitated by providing fresh feed at the feeding fence

-When cows are housed in stables with slatted floors, rubber mats or an equivalent surface should be present in the resting spaces to avoid that cows lie down on the slatted floors

-Cows with chronic subclinical mastitis should be removed from the herd and a bacterial examination of all cows’ udders should be reviewed at least once a year.

Adult cattle management

Even though adult cattle is less sensitive to disease than calves, infection pressure should be kept as low as possible. Consequently, the stables of adult cattle should be fully empty, cleaned and disinfected at least twice a year. Before animals enter, the stable should be dry.

In order to limit spread of hoof-related pathogens, adult cows should pass through a hoof disinfection bath regularly, depending on the infection pressure present on-farm.

Animal groups

As the animals grow older, age is no longer the most important factor to group the animals. However, especially dairy cows should still be divided into groups according to their production cycle. As a bare minimum, the dry cows should be separated from lactating cows. Fresh cows can be kept separately to assess their health. Ideally, also first lactation cows are grouped together, and a high, (mid-,) and low lactation group can be made.

Working organisation and equipment

Disease transmission between animals

Preferably calves and young stock are housed in another stable than the adult cattle, or at least well separated (i.e. no physical contact and a distance of minimum 3 meters between the boxes) to avoid disease transmission through direct and indirect contact, including aerosols and air transmission (Maunsell et al., 2011). To further avoid indirect contact, the same measures as for the quarantine and hospital pen (e.g. farm-specific boots and clothing, washing hands) can be applied. Injection needles should be dedicated for each age group and regularly replaced.

Age groups

When calves leave their individual housing, regrouping to group pens of the same age is advised. Initially this means that variation in age of 1 week is allowed, for older calves variation in age of about 8 weeks can be allowed (Gulliksen et al., 2009). Calves that do not grow well, should not be put back in a younger age group, but have to be examined for the presence of disease and should be isolated to avoid that they serve as a continuous source of infection.

For calves, the transmission through aerosol is highly important. Therefore the position of the different age groups in the stable is important. When there is a specific direction in the airflow within the stable, and if the stable hosts different age groups, attention should be paid that air flows from the younger calves to the older animals. If necessary the climate (temperature, humidity, …) should be controlled in the stables (Daugschies et al., 2005; Gorden & Plummer, 2010).

To avoid stress and lesions, it can be decided to group beef cattle per sex (Sanderson et al., 2008).

Working lines

It was already mentioned that sick animals and animals in quarantine should be taken care of at the end of the daily routine. It is furthermore recommended to work from young to old in the daily working scheme, i.e. farm-specific working lines (Maunsell & Donovan, 2009; Gorden & Plummer, 2010; Maunsell, 2011). Farmers often argue that this from-young-to-old scheme is difficult to apply, since lactating cows first have to be milked to give this milk to the calves. This issue can be solved by feeding the calves with tank milk or by performing the milking of the cows and feeding of the calves by different persons. 

Hygiene lock

Ideally a sanitary transition zone (changing clothes, washing hands) is present for each age group of animals and is correctly used. The application of these biosecurity measures together with the use of age-specific material can be encouraged by providing physical barriers between the age groups. This can be a different stable, but also a bench or door which has to be passed to go to the next age group.

Material and disease transmission

For each age group the use of age-specific material is advised and feeding utensils should only be used for feed, i.e. no double use for removing manure. Distinction between age-specific material or feeding-specific utensils can easily be made by labelling the material. Preferably, feeding utensils are cleaned and disinfected after each use.

Sharing tools with other farms that came into contact with the animals, such as a feed mixer or a hoof care crush, should be avoided. If it cannot be avoided, these tools should be cleaned and disinfected before entering the farm.