Bovine Mastitis Control Strategies with Emphasis on Developing Countries

Abstract

Mastitis is a major problem that reduces milk production and quality in the whole world. Because mastitis is an endemic disease, farmers in most countries have mastitis control programs to keep mastitis prevalence at a low level of less than 5%. However; a mastitis control program cannot be implemented unless the prevalence and the risk factors of mastitis are known. Therefore; a systematic review was conducted to provide broad information on mastitis prevalence and associated risk factors and propose appropriate control strategies with emphasis on developing countries. This book chapter recommends dairy farmers to monitor milking cow’s udder health, improve hygiene, regular use of teat dips, practice dry cow therapy, appropriate and effective treatment of affected animals.

1. Introduction

Mastitis prevalence rates from the developing countries tend to be much higher than those from developed countries. Plozza et al. [1], working in New South Wales in Australia and using the California Mastitis Test (CMT), reported a mastitis prevalence rate of 29% while Fadlelmoula et al. [2] reported a prevalence rate of 27.6% from Germany. Elbers et al. [3] reported the lowest prevalence of 12.7% from The Netherlands.

In Bangladesh Rahman et al. [4] used CMT and estimated that the prevalence of mastitis was 19% in the dry and 44% in the wet season. In Uruguay, Gianneechini [5] used CMT and reported a mastitis prevalence of 52.3%. Figures from Ethiopia vary from between 10–23% for clinical mastitis and 22–71% for subclinical mastitis. Abera et al. [6] from Ethiopia using the CMT found an average prevalence of 46%. Of this 10% was due to clinical mastitis and 36% from subclinical mastitis. Using the same method (CMT), Almaw et al. [7] reported a subclinical mastitis prevalence of 25.22% from Gondar, Ethiopia. Mekibib et al. [8] from a different location also in Ethiopia reported a cow level mastitis prevalence of up to 71%. Of this prevalence, 22.4% was due to clinical mastitis and 48.6% was due to subclinical mastitis. Girma [9] conducted a study on prevalence of bovine mastitis on crossbreed dairy cows around Holeta, Ethiopia, and found that the prevalence of mastitis in general was 44.1%. About 10.3% was due to clinical mastitis and 33% was due to subclinical mastitis. According to Biffa et al. [10] the general prevalence of mastitis in lactating dry cows in southern Ethiopia was 34.9%.

Karimuribo et al. [11], reporting from Tanzania and using the CMT and culture, estimated the prevalence of mastitis at 75.9% and 43.8%, respectively. Kivaria et al. [12] found the prevalence of mastitis was 43.3% in smallholder dairy cows in Dar es Salaam region, Tanzania.

In Rwanda official publications indicate that the prevalence of subclinical mastitis was more than 67% by Mpatswenumugabo et al. [13] and 52% by Iraguha et al. [14]. Based on sampling from bulk chilling tanks in Nyagatare District, Chatikobo [15] reported a prevalence rate of 58.6%. However, this figure does not indicate mastitis prevalence at farm and cow levels which are the focus of any mastitis control measures. Moreover, the report of Shem [16] broadly states that mastitis is a problem in dairy herds in Rwanda but does not have adequate figures.

2. Mastitis risk factors

The risk factors associated with mastitis are many and no single article has ever attempted to deal with all of them. Individual factors that are of particular importance in the individual mastitis cases have been extensively reviewed by Cunningham [17].

According to Abera et al. [6], Almaw et al. [7], Mekibib et al. [8], and Biffa et al. [10], in Ethiopia the main risk factors identified to be associated with mastitis are age (over 6 years), housing systems (muddy houses), lactation stage (over 6 months), wearing gloves, using paper towels, feeding after milking, injured teat, udder conformation, udder condition (unwashed udder), season (long rain season), and system of production. Benhamed et al. [18] from West Algeria also added breed as an important factor. Karimuribo et al. [11] and Kivaria et al. [12] from Tanzania identified body condition score, parity stage, and udder consistency, housing condition and milking practices as important factors.

According to Iraguha et al. [14], the prevalence of infected quarters increases with age, peaking at seven years and teat end conditions (damaged teats). Most new infections occur during the early part of the dry period and in the first two months of lactation, especially with the environmental pathogens.

The greater the prevalence of the disease in the herd, the greater the risk of new infections, Blood and Anderson [19] assert that the incidence of mastitis is greater in Holstein Friesian than in other breeds.

High milking rate and large teat canal diameter have been associated with increased somatic cell count (SCC) or risk of intra-mammary infection. Normal teat ends with a slight amount of callosity do not appear to increase the risk of mastitis and may be a beneficial response of the teat during machine milking. However; abnormal teat ends that are extremely rough and showing evidence of hyperkeratosis are associated with an increase of new mastitis infections as [14] and Vitamin E, vitamin A and selenium may be involved in resistance to certain types of mastitis [20].

Poor housing and bedding quality management increase infection rate and incidence of clinical mastitis due to environmental pathogens [21]. According to Rahman et al. [4] a clean environment and udder were mandatory for reducing mastitis in Bangladesh. This would apply across the whole world. Although very rare, intramammary infection (IMI) may also occur due to hematogenous spread.

Doherr et al. [22] from Switzerland reported that the risk factors associated with subclinical mastitis in dairy cows in Switzerland were dry cow therapy, nutrition and poor milking practices. Elbers et al. [3] working from the Southern Part of The Netherlands identified trampled teats, no disinfection of the maternity area after calving, consistent use of post-milking teat disinfection, use of a thick layer of bedding in the stall, and the stripping of foremilk before cluster attachment as the major risk factors. Oliver et al. [23] from Tennessee identified calving time, milking practices, age at first calving, presence of pathogens on the body as significant factors. Fadlelmoula et al. [2] working on large scale dairy farms in Thuringia-Germany mentioned early stage of lactation, summer calving, udder cleanliness, milk yield and peri-parturient diseases as predisposing factors for developing mastitis. Plozza et al. [1] working on mastitis and its associated risk factors on dairy farms in New South Wales revealed that wearing gloves, using paper towels, and feeding after milking were the risk factors associated to mastitis prevalence whereas dipping teats was not significantly associated.

3. Types and causes of mastitis

In addition to the foregoing classification, mastitis can also be divided into contagious and environmental mastitis [8]. Bacteria involved in the pathogenesis of contagious mastitis include Staphylococcus aureus, Streptococcus agalactiae, Corynebacterium bovis and Mycoplasma bovis [17]. Environmental causative agents include the streptococci, Streptococcus uberis and Streptococcus dysgalactiae and the coliforms Escherichia coli, Klebsiella spp., Citrobacter spp., Enterobacter spp., and Pseudomonas spp. [5].

Minor pathogens include coagulase-negative Staphylococcus spp. and the list of uncommon pathogens is endless: Trueperella pyogenes, Nocardia spp., Pasteurella spp., Mycobacterium bovis, Bacillus cereus, Serratia marcescens, anaerobic bacterial species, fungi and yeasts [17].

The source of mastitis is therefore either contagious pathogens or environmental pathogens. Infection of each mammary gland occurs via the teat canal, the infection originating from either an infected udder or the environment. In dairy cattle the infection originating from infected udders is transmitted to the teat skin of other cows by milking machine liners, milkers’ hands, wash cloths, soils, bedding, contaminated milk, washing water, drying cloth/paper, udder and any other material that can act as an inert carrier [24].

With mastitis, the danger of bacterial contamination from affected milk rendering it unsuitable for human consumption looms large. Coupled with this is the potential for food poisoning or interference with manufacturing process or, in rare cases, a mechanism of spread of disease to humans and potentially antimicrobial resistance to humans [25].

4. Mastitis detection

The diagnosis of clinical mastitis is not difficult if careful clinical examination of the udder is done as part of the complete examination of a cow with systemic clinical findings. Examination of the udder is sometimes omitted in a recumbent animal only to find later that severe mastitis was present [26]. The diagnosis of mastitis depends largely upon the detection of clinical abnormalities of the udder and gross abnormalities of the milk or the use of an indirect test like California Mastitis Test to detect subclinical mastitis [27].

The detection of subclinical mastitis can be either by surveillance of the herd through periodic examination of the udder health by evaluation of milk at the herd level or at the individual cow level. This is done by examination of either bulk tank milk or individual cow tank milk or individual cow composite milk samples using indirect tests for evidence of subclinical mastitis.

There are many chemical methods for mastitis detection at farm level and these include pH, chloride test and the CMT [28]. The majority of the chemical methods depends upon the demonstration of abnormalities in milk composition and is therefore indirect tests for mastitis. Abnormal changes may not appear with regularity in the milk of all cows having an udder infection. In most cases a positive test indicates an infected quarter, but a negative test does not indicate that the quarter is not infected [28].

The most commonly indirect tests used for the existence of mastitis include the use of chemicals. Milk from affected udders is abnormally alkaline with the degree of alkalinity depending upon the severity of inflammation. Abnormal milk may have a pH as high as 7.4; where as normal milk has a pH of 6.4−6.8. The reaction of milk may be determined by several different methods, the most common of which is the use of indicators that change color at near the normal milk pH. The pH should be determined on freshly drawn milk although milk held at refrigerator temperature for 24−48 hours may be used [28]. Due to the influence of fat on the result reading, it is necessary to use milk drawn at the beginning of milk removal. The test is of a little value for cows in late lactation because will result in false positive alkaline reaction [28].

The recent technologies that can used in field settings include portable devices such as Draminski®, PortaSCC® test, California Mastitis Test (CMT) and the UdderCheck® test [14] all these tests for presence of indicators of inflammation of the quarter/udder.

5. Mastitis control strategies

The disease cannot be eradicated but can be reduced to low levels by good management of dairy cows and its environment. After each milking the teats should be dipped or sprayed with disinfectant teat dip and keep cows standing for at least 30 minutes after milking (e.g., offer them food). Treat clinical mastitis using antibiotics in intra-mammary infusion and/or injection. It is also highly recommended to give intra-mammary infusions or injection under veterinary supervision.

Hygiene and milking best practices such as wash dirty udders before milking with clean water and dry thoroughly, wash and disinfect hands before milking each cow, foremilk all teats into a strip cup and check the milk for mastitis, milk cows affected by mastitis last and discard the milk and treat all functional quarters of cows at drying off with specifically designed infusions of antibiotics will reduce the incidence of mastitis. Cows with repeated clinical mastitis should culled.

When hand milking is used; practice proper milking hygiene such wearing milking gloves, wash hands and equipment thoroughly, etc. When milking machine is used it has to be properly designed, operated and maintained. Keeping the cows healthy such as improved immune function of the udder would prevent mastitis even if bacteria enter the teat canal (Figures 1 and 2).

Figure 1.

Teat dipping after milking.

Figure 2.

Antibiotic infusion in infected teat.

5.1 Standard operating procedures for mastitis control and prevention

The following routine will reduce the number of infected cows and clinical mastitis by at each milking: adopt good cow management practices as the essential basis for a mastitis control routine (e.g., feeding, housing, hygiene). Reduce exposure to pathogens by cleaning thoroughly all equipment used when milking, hygiene of milkers, avoid housing cattle under dirty conditions preferably change organic bedding materials regularly, wash dirty udders before milking with clean water preferably with the hand, a disposable paper towel or a disinfected cloth and dry thoroughly.

Teat dipping/spraying using appropriate products (e.g., Chlorine, Chlorhexidine, hydrolyzed fatty acids, Iodine, Quaternary ammonia based, etc. Adopt practices that prevent the occurrence of teat lesions and always milk cows affected by mastitis last and discard the milk. Additional benefits can be obtained by disinfecting hands before milking each cow, using individual paper udder cloths, dipping teat cups in disinfectant before each cow is milked.

Reduce mastitis in non-lactating cows in the dry period by avoid using low lying grazing land and damp wooded areas where flies are common, use good fly control measures and treat cows at drying off with antibiotics recommended by veterinarian.

Three key control measures include teat dipping by appropriate variant, practice dry therapy program and effective treatment of sick animals.

5.2 The do’s for hygienic milker

Milkers may spread mastitic pathogens and other diseases e.g., typhoid and paratyphoid fever, tuberculosis, dysentery, scarlet fever, septic sore throat, diphtheria and cholera are milk-borne and enter the milk from infected workers causing disease infection to consumers.

Therefore, milkers should be in good health and their hands free from any infections. Hands with infected wounds can add bacteria to milk and cause milk contamination and subsequent human infections. Have a medical check for diseases such as typhoid, tuberculosis, dysentery, diphtheria and cholera regularly from a medical center is mandatory.

Wash your hands thoroughly before milking each cow to avoid any contamination and disease’s spread. Wear clean clothes and cover your head or have short hair to prevent loose hairs falling into the milk.

Ideally, milkers should use disposable milking gloves that are maintained clean and regularly disinfected during milking, particularly between cow.

Milk quickly and quietly in a stress-free environment and milk the cows at regular times daily is very important.

5.3 Standard operating procedures for a good environment in hygienic milk production

The milking shed should be constructed on windward side of roads to avoid dusty conditions in the shed. The floor should be constructed of cement with a strong concrete finish. The milking shed must be kept clean and dry and well-ventilated house to allow sufficient supply of fresh air. Avoid buildup of dung, urine or excreta as this may cause floors to be slippery and create suitable environment for bacteria growth. Avoid using muddy pens which are contaminated with feces as this causes outbreaks of mastitis.

Waste storage areas for example: manure heaps should be sited away from milk shed avoiding possible pollution of watercourses, lakes, reservoirs, wells, boreholes and underground water. When bedding material is used in the pens it should be changed frequently, preferably daily. A good supply of clean water is required for cleaning the floors.

5.4 The do’s of the milking cow

The cow should be in health condition and regularly examined for diseases such as mastitis and zoonotic diseases.

The body of the cow should be free of soil, dirt and manure and contamination of milk from external sources such as animal hairs and dirty water dripping from the cow’s body should be avoided. Use regular milking routine and proper milking techniques which do not strain the teats. Use teat dip disinfectant after each milking to reduce udder infection by bacteria. Renew bedding materials frequently, avoiding sawdust where bacteria proliferate.

5.5 Standard operating procedures for cleaning utensils in hygienic milk production

Dairy utensils should be of approved type, seamless with close fitting lids. They should not be used for any other purpose. Do not use containers that previously contained paint, paraffin, herbicides and other chemicals because traces of these substances can taint your milk reducing its quality. After using utensils, they must be rinsed with clean cool or warm water. Scrub the utensils using a detergent, such as washing soda solution (1.5 tablespoons washing soda in 5 liters of water) and a disinfectant such as bleach (2 tablespoons bleach in 4.5 liters of water). In developed countries specialized washing acid and alkaline products are used.

Rinse several times with clean hot water to remove any remaining detergent and disinfectant. When disinfectant is not available, after scrubbing the equipment in hot detergent solution, disinfect the utensils by immersing it in hot (above 75°C) water for at least 3 minutes.

Milking buckets, cans and measuring jugs should be stored turned upside down on a rack to keep them free from dust.

5.6 Standard operating procedures for hand milking in hygienic milk production and mastitis control

Good hand milking is a skill which can be learned. Good hygiene is of the utmost importance because the level of hygiene influences the quality of the milk. There are a number of general rules which should always be followed:

Maintain clean and healthy cows. Keep a clean milking environment. Keep milking routines and times consistent and regular. Milk in the correct way to avoid the damage of the teats and udder. Wash hands with soap and clean water before milking and between milking of cows. Wash the udder with warm water and dry the with a clean dry cloth. Make the first draw into a strip cup to check for mastitis and throw away from the milking area even if it appears clean. Use clean containers for milking. Cows with mastitis should be milked last and their milk discarded. The milker should not: (a) have long nails, (b) sneeze or cough, (c) smoke.

Milk from cows under antibiotic treatment should not be sold until, at least, three days after the last treatment or as advised by the veterinarian.

After every milking, dip/spray the teats into an “antiseptic dip.” Release the cow from the milking area as soon as milking is finished.

Milk filtering (to reduce contamination) using clean sieve/filter cloth. After milking and filtering, cover the milk to avoid contamination and move the milk to a clean and cool area. To reduce the dust content of the air in the shed avoid: sweeping the milking area before milking, handling hay and feeds before and during milking, brushing the cow immediately before milking, dusty bedding and accumulation of dirt and dust in the pens.