Chapter 1: Introduction
Cattle are raised mainly for meat and dairy products in Mauritius. Cattle breeding are an essential component of modern agriculture. According to norms, safe food of animal origin must be free from pathogens and contaminants. There is a need to reduce the risk and if possible, eliminate it at the ‘on the farm stage’. Cattle disease compromise animal welfare, reduce productivity and can also infect human beings. Sanitary conditions and perceptions in cattle breeding farms are very important to ensure a better health of the cattle and consumers of the products. The main reason for disease prevention and management for breeders is the gain in productivity. Sanitary conditions are very crucial in the disease prevention and management.
The health of the cow and its environment, improperly cleaned and sanitized milk handling equipment, and workers who milk cows and come in contact with milk due to a number of reasons could serve as sources of microbial contamination of milk (Yirsaw A.W,2004). Contaminants in the form of chemical residues are also of concern to public. Controlling the safety of food of animal origin at the primary production stage therefore involves all the measures (implemented at the farm or production unit level) necessary to ensure that these contaminants do not end up in animal products, or, if they do, that their levels do not exceed the maximum permissible levels, notably the maximum residue limits and microbiological criteria set by Codex Alimentarius Commission (OIE, 2008). Many factors influence milk composition and hence the nature and abundance of the microbial load. The conditions of raw milk production, in particular the hygienic practices of farmers (e.g washing of milking equipment and pre and post milking udder preparation), determine the contents in useful products and spoilage microorganisms (lafarge V et al, 2004).
Henceforth, this case study of dairy cattle breeders, help in meeting the following objectives of the project.
The main objective of the study is to assess sanitary practices and perceptions in dairy cattle breeding farms.
The specific objectives are:
To assess the sanitary milking practices in dairy cattle breeding farm through pre-milking teat disinfection, foremilk rejection and post-milking teat disinfection.
To investigate on sanitation practices in dairy cattle breeding farm through practices of cleaning and sanitizing milking equipment.
To assess level of awareness on mastitis and sanitary conditions at farmers working place.
To evaluate responses based on survey questionnaire on sanitary practices and perceptions on dairy cattle breeding farms.
Chapter 2: Literature Review
Evolution of dairy cattle breeding
Mauritius is categorized as a net food importing country. The dairy production contributes negligibly to the country’s economy with only 2% local milk production (AREU, 2007). According to Milliken (1986), there were about 22,000 milch cattle in 1914, representing a little more than 50% of the total cattle herd at this time (Heera MK, 2008). However the number of cattle head and farmers has been steadily declining over the years, leading to the current situation of only 7150 heads for 1758 breeders (CSO, 2008). Traditionally, the dairy industry in Mauritius was dominated by backyard producers, mostly women. But many of them abandoned farming in the 1980’s to take higher paid jobs in the textile and clothing manufacturing industry (Ackbarally N, 2009). Simultaneously the sanitary problems (number of complaints due to lack of sanitation) and diseases, poor management also accounts for the decline.
Food crisis in relation to dairy cattle rearing
The food crisis which has hit with alarming speed and force the planet over the past recent years has showed how vulnerable net importing countries, like Mauritius, are against such situation. The milk (UHT and powdered) import bill has increased from Rs 975 M in 2001 to Rs 1.8 billion in 2007, representing a 85 per cent rise, while the import volume has remained unchanged (around 17,500 tonnes) (Anon, 2009a). Since the early 1980s milk consumption has grown more than 3 percent per year in developing countries and is projected to grow even faster through 2020. Meat consumption has been growing about 5 percent per year and is expected to grow 2.7% per year through 2020 compared to a low 0.6% per year in rich countries (Zessin K.H, 2002). Hence in response to the global rising food prices and shortages, the government is implementing measures to foster local production of milk and meat to mitigate, in short and medium term, the dependency of the country on imported food commodities. To stimulate dairy production, the government has introduced a battery of grants and loans to purchase equipment, import improved genetic breeds and acquire land for grazing (Ackbarally N, 2009).
Importance of Sanitation in dairy cattle breeding farm
‘Sanitary condition’ is defined as the state of sanitation whereby sanitation is the formulation and application of measures designed to protect public health (wikipedia). The cattle breeding are often viewed as a lucrative opportunity. There are nevertheless a series of complications which may arise during such an event if proper hygiene and sanitation is not maintained. When it comes to sanitation at farm, it is closely linked with “Food safety” which is now universally recognized as a public health priority. There are a series of precaution that can be taken by farmers, right at the first stage of the food chain, to optimise the food safety control of products of animal origin (OIE, 2006). This inevitably means controlling the health status of the animals from which food products are derived.
World organization for animal health (OIE)
In this age of globalisation, ensuring healthy, hazard-free food is one of the key issues for international organisations working in this field. To this end, the World Organisation for Animal Health (OIE), the Food and Agriculture Organization of the United Nations (FAO), the World Health Organization (WHO) and the Codex Alimentarius Commission (CAC) work closely together, each in its area of competence (OIE, 2008). Since 2002, the OIE has had responsibility for “animal production food safety”. The renewed importance conferred by the Sanitary and Phytosanitary measures (SPS Agreement) to the OIE and to WHO/FAO has spurred the interest of countries around the globe (Zessin K.H, 2002).
Preliminary Environmental report
Cattle rearing do have certain direct and indirect impacts on the environment which require special attention while setting up a farm. Those impacts are mostly associated with solid and liquid waste originating from the farm such as; wastewater from cleaning activities, urine, and manure. Other problems such odour nuisance and flies nuisance are not to be omitted. In case the farm is near residential areas, consultation with neighbours and all other bodies who are likely to be affected by the farm is compulsory. According to Environmental Protection Act 2002, livestock rearing on a scale of up to 20 heads require a Preliminary Environmental Report in which all the environmental and socio-economic parameters are addressed and their impacts are identified and taken into account in the project design (Anon, 2009b).
Dairy cattle breeding
There are mainly three types of farms in Mauritius. These are:
Small Scale farms
Locally cattle breeding are more of a family business. Cattle rearing are carried out in a traditional manner in the backyard as a part time activity. The small cattle breeders also known as cowkeepers mostly live in the country side and they own on average two to three lactating cows that are kept in enclosed shed(RATES, 2004). The level of inputs and management vary greatly among the farmers and they are generally low because of limited facilities and lack of financial resources.
Medium Scale farms
Medium scale farm is quite similar to small scale farm. However they have slightly better management practices in terms of inputs (e.g. better feeding system) and modern techniques are applied e.g. use of milking machine ( Ackbarally N, 2009).
Large Scale farms
Presently there are two private farms namely Golden Cream Dairy farm ltd at Salazie and SKC Surat Co Ltd at Rose-Belle who are operating at large scale for commercial milk production. Another type of large scale farms which have almost ceased to exist is the Government Dairy farm. In the past there were three Government dairy farms that would keep around 200 head of cattle. Richelieu Livestock Breeding Station (RLPU) has been converted into a quarantine station and recently the Palmar Livestock Breeding Station has been closed. Presently there exists only the Curepipe livestock Research station where other species of livestock are also reared with the main objective to carry out research and development activities in livestock production and training for the benefit of farmers.
Guiding objective for good dairy farming practice
The guiding objective for good dairy farming practice is that milk should be produce on-farm from healthy animals under generally accepted conditions. This is achieved by applying good agricultural practice in the five areas.
Cows that produce milk need to be healthy and an effective health care programme should be in place. Animal health care includes different veterinary treatments given to the animals for early detection of diseases, prevention of disease spread among healthy animals, prevention of transmission of zoonoses and to ensure traceability (FAO/IDF, 2004). It is important to have strict control of any animal introductions to prevent the movement of the infectious diseases onto the farm. Sick animals are liable to be a major source of disease to healthy animals and hence need to be segregated to reduce the chances of diseases spreading. In case where animals are imported or brought from other local farms, they need to be kept in isolation from the existing herd for about 30 days. This is done again to prevent contamination of existing herds by parasites and pathogens (AREU, 2004). Other activities such as vaccination and deworming schedules, hoof management and routine health assessment form part of a good Health Management.
Guidelines to be followed for effective housing of cows
Dairy housing systems have a substantial impact on the overall health and longevity of dairy cattle (Barberg A.E et al, 2007). In addition to keeping animals healthy, a critical part of husbandry is also to make sure they are kept visibly clean. It is of particular importance, to reduce the possibility of contamination of the food, for milking animals and for animals destined for slaughter not to have dirty outer coats. A major influence on the cleanliness of the animals is the type of housing, the material used as bedding and the underfoot conditions if the animals are kept outside (A M Johnston, 2000). Where cows are kept indoors it is important that suitable and adequate buildings be provided if the cows are to be fully productive. Good dairy farm buildings are extremely important in considering any of the hygienic aspects of milk handling (WHO, 1962). The design of the housing system is also important so that there is adequate space and facilities to optimize feeding, collection of manure, cleaning, washing, artificial insemination.
The housing system can be either loose or tied system with adequate space and facilities to optimize feeding, collection of manure, cleaning, washing, artificial insemination and milking (AREU, 2007).
The general layout of a dairy farm should be according to the number and category of animals to be housed. The cowhouse is a specialized building which should be carefully designed and constructed so as to provide comfortable and healthy housing for the cows and at the same time to enable them to be milked in clean conditions. Housing must be managed hygienically to avoid soiling of animal. A standing of 1.5m long has been found most suitable to enable cows to lie clean, but with the smaller breeds of cow 1.4m or less may be sufficient (WHO, 1962). Moreover it should be free of obstruction and hazards; dead ends, and steep and slippery pathways should be avoided. It should be resistant to adverse weather conditions and consequences thereof especially cyclones, unseasonal change causing cold or heat stress (FAO/IDF, 2004). The windows should be fitted with hinged shutters to be used in case of cyclonic conditions.
The floor should be non-slippery to minimize slipping and bruising due to rough uneven floors. Unsuitable floors may inhibit mounting or lead to injuries during mating. The floor should be preferably sloping 10 cm above surrounding ground to enable drainage of urine in a canal leading to a suitable point of disposal as required by the Sanitary Authority (AREU, 2007).
Plastering of the wall to a height of at least 1.5m is recommended to prevent accumulation of dirt, disease germs and to facilitate cleaning (WHO, 1962). Cowshed should be provided with at least two doors, one opening on the feeding passage and the other one on the manure cum milking passage.
Ventilation and lighting
The regular renewal of the air in a cowshed is essential for the maintenance of the health of the cows and prevention of contamination of milk (WHO, 1962). The cowshed should have sufficient openings to allow natural ventilation and adequate sunlight. This will enable proper supply of fresh air to remove humidity, allow heat dissipation and prevent build-up of gases such as carbon dioxide, ammonia or slurry gases (FAO/IDF, 2004). Direct sunlight helps to keep the shed dry and would act as a germ killer.
Water supply plays an imminent role in maintaining a proper sanitary balance in breeding farms. Besides being used for drinking purpose, efficient water supply helps in cleaning and other activities leading to part of proper sanitation. The cow needs a lot of water (up to 50L daily) to be able to produce saliva for rumination and milk production. It is best to allow the animal continuous access to ample fresh and clean water (AREU, 2004). Water is an obvious potential source of pathogens because it can contain nutrients from feed or manure and be contaminated with pathogens, thereby serving as a vehicle to contaminate or infect animals on consumption (CAST, 2004). E. coli 0157:H7 is found commonly in water troughs on farms and feedlots and persists in these environments for as long as four months (Lejeune J.T et al, 2001). Water supplies should be clear and free of excrement (FAO/IDF, 2004).
For healthy living and proper growth, reproduction and milk production, dairy cattle require a daily balanced diet. The feed contains nutrient namely carbohydrates, fat, proteins, minerals (e.g. calcium, phosphorus) and vitamins (A, D, E, K). Moreover, foodstuffs which are fed to animals must be free from both pathogens and undesirable residues. Since Mauritius is mainly based on a zero-grazing system, breeders have to make provision for forage based on a cut-and-carry fodder system. The source of forages varies among breeders; they are collected from Sugar Cane Estates or along roadsides, fallow lands, riverbanks, and state lands or vegetable fields (Heera M.K, 2008). Withholding periods should be applied to forage crops if they have been treated with agricultural chemical, prior to use as feed.
Control storage conditions of feed
The different control measures in relation to feedstuffs and its storage are as follows:
Feeds intended for different species should be separated. No animal material should be included in dairy cattle feed rations.
Appropriate storage conditions should be ensured to avoid feed contamination. It should be ensured that animals are not able to come into contact with contaminants in areas where these feed products are stored and mixed.
Hay and dry feeds should be protected from a moist environment, silage and other fermented crops should be kept under hermetically sealed conditions(AREU,2004)
Moldy feed should be rejected (FAO/IDF, 2004); feeding of any moldy stock feed to milking cows should be avoided. Particular care should be taken with wheat bran, silage, hay, bagasse, cotton seed cake as these contain poisonous fungal toxins that can be transferred to milk.
Fungal mycotoxins may also be present in pasture. In New Zealand, the ingestion of saprophytic fungus containing the toxin, sporidesmin, causes the disease facial eczema with impaired liver function, photosensitivity, decreased milk production and sometimes death (Ferraud C, 1995). Although the disease is uncommon in other temperate countries, it is important to realize that increased forage use carries the risk of an increased incidence of pasture borne mycotoxicoses.
Milk plays an important role in our daily diet. Cows’ milk contains a wide array of key nutrients that help support human health. It is an excellent source of protein, calcium, potassium and phosphorus. Apart from being a nutritional food, milk has a high water activity, moderate pH of 6.4 to 6.6 and ample supply of nutrients, making for an excellent medium for microbial growth. There is wide spectrum of bacteria present in nature which can contaminate milk rendering it unsafe for human consumption or unfit for further processing.
Human pathogens known or likely to contaminate raw milk
Microorganisms are widely present in animals and in their environment. Disease in animals is inevitable on farms, no matter how good the husbandry (Johnston, 2000). The diseases that form the greatest threat to animals are caused by microorganisms that invade the body. Diseases could be infectious (of viral or bacterial origin), non-infectious (caused by parasites) or metabolic (caused by imbalanced diet). Specific infectious diseases are generally restricted to the large farms and metabolic diseases are more commonly seen in cattle belonging to small breeders (Sibartie D, 2001). Healthy dairy cattle are considered a reservoir for several of the most important food borne human disease pathogens (Tauxe, 1997). Nontyphoidal Salmonella spp. and Campylobacter jejuni are considered important treats to food safety because of the enormous number of illness they cause. Cattle have been shown to carry Salmonella at rates as high as 64% (CAST, 2004). Listeria monocytogenes and Escherichia coli 0157:H7 are priority pathogens because of the severity of symptoms associated with infection and because of the number of deaths that occur in infected people. All of these pathogens are shed in cattle feces and can contaminate dairy farm premises including unpasteurised bulk tank milk (Ruegg P.L, 2003).
Milk borne diseases
Human-health threats from livestock come in two basic forms: (i) zoonotic diseases, and (ii) food-borne illnesses. Zoonotic diseases are those that arise in animals but can be transmitted to humans. Potentially pandemic viruses, such as influenza, are the most newsworthy, but many others exist, including rabies, brucellosis and anthrax (FAO 2009).
A joint FAO/WHO Expert Committee (1970) on milk hygiene classified milk-borne diseases:
infections of animals that can be transmitted to man:
Primary importance: Tuberculosis, Brucellosis, Streptoccocal infections, ;Staphyloccocal enterotoxin poisoning, Salmonellosis, Q fever.
Lesser importance; cowpox, Foot and mouth disease, Anthrax, Leptospirosis and Tick-borne encephalitis
infections primary to man that can be transmitted through milk:
Typhoid and paratyphoid fevers, Shigellosis, Cholera, Enteropathogenic Escherchia coli, Non-diarrhoeal diseases, Streptococcal infections, Staphylococcal food poisoning, Diphtheria, Tuberculosis, Enteroviruses and Viral hepatitis (Kamalam S, 2005)
Outbreaks associated to milk
Warnings to consumers about the risks of drinking raw milk have been stepped up over recent years because health professionals are trying to protect health and have seen a resurgence in milkborne diseases that had dropped dramatically with pasteurization, as raw milk has become trendy and its marketing has increased (Szwarc S, 2009).
Worldwide, mastitis is the most common disease in dairy cattle (Tan et al, 2009). Mastitis is defined as an infection of the udder, caused by bacteria entering the quarter through the teat end. According to the US national mastitis council(1996); mastitis is an inflammation of the mammary gland in response to injury for the purpose of destroying and neutralizing the infectious agents and to prepare the way for healing and return to normal function ( Fadlelmoula A.A, 2007). This results in physical, chemical and microbial changes in the milk. It can be caused by a variety of bacteria or even fungi, the most common in Mauritius being Staphylococcus epidermidis (Sibartie D, 2001).
Mastitis in dairy cattle represents a disease problem which is difficult to prevent or control effectively, since so many different workers have pointed out special instances which indicate that the susceptibility to mastitis manifested by related animals might have genetic basis: various studies have given heritability estimates for mastitis resistance ranging from 0.05 to 0.38 (Warwick E J et al, 1979).
Principles of mastitis control
Worldwide, farmers have achieved tremendous success in reducing the incidence of contagious mastitis by adopting five basic principles of mastitis control (Ruegg P.L, 2003):
Postmilking teat disinfection
Universal dry cow antibiotic therapy
Appropriate treatment of clinical cases
Culling of chronically infected cows
Regular milking machine maintenance
Sources of contamination of raw milk
There are several principal sources of contamination of milk. From the time the milk leaves the udder, until it is dispersed into containers, everything with which it comes into contact is a potential source of more microorganisms.
Within the udder
For many years, it was believed that milk drawn directly from the udder of a healthy cow was a sterile fluid, that is, it contained no living microorganisms (Yirsaw A.W, 2004). In healthy cows, many microorganisms resides in the teat cistern, teat canal and teat apex. Natural flora within the udder of healthy animals is not considered to contribute significantly to the total numbers of microorganisms in the bulk milk, nor the potential increase in bacterial numbers during refrigerated storage (Murphy S.C et al, 2000). The first few streams of milk from each teat should be collected, separated, discarded. This flushes out the organisms that entered the teat through the teat opening (FSA, 2006).
In cows having mastitis, the infected udders can shed lots of microorganisms into the milk. Selim and Culor (1997) found that Streptococci and coliforms are the most dominant isolated bacteria from milk followed by Staphylococcus spp (Yagoub S.O et al, 2005 ; Murphy S.C et al, 2000).
Exterior of the udder
Usually the microorganisms from the skin of the animals and the microorganisms from the environment where the cow is kept and milked cause contamination to the exterior of the udder. Common organisms associated with the bedding materials are staphylococci, streptococci, coliforms, spore formers, and other gram-negative organisms (Murphy et al, 2000; Elmoslemany A.M, 2009).
Surface of milk handling and storage equipment
The most important factor affecting the total bulk milk bacteria count is the cleanliness of the milking system. Utensils and equipment are known to be the greatest sources of contaminants. They may account for as much as 100,000 to billion organisms per milliliter (Murphy S.C et al, 2000). Pails, strainers, milking machines, cans, pipes bottles, and other equipment used for the handling of milk are sometimes not properly washed and sanitized. Organisms survive in the cracks, corners, crevices, dents, scratches and other irregularities of the utensils. Such neglect affords ideal conditions for the growth of microorganisms before the utensils are being used again. Refrigeration is also essential to prevent or slow the growth of bacteria in raw milk.
The consumers are nowadays well conscious about food hygiene and they demand high standards of milk quality. Hence it is fundamental that breeders respect the quality criteria of their product to satisfy the demand and to remain in competition. Milking performed under strict hygienic conditions, with strict attention to sanitary practices, will reduce the entry of microorganisms into the milk. Naturally the fewer the organisms that get into the milk, the fewer have a chance to grow.
Personal hygiene of milk handler
At all stages hygiene is necessary to prevent contamination of milk. This starts from the person first handling the milk that is the milker and all throughout its handling. It is the responsibility of the milker to follow strict level of personal hygiene to prevent direct contamination of the milk.
Personal hygiene of milk handler includes the following (CAC, 2004):
The milker should be in good health; those with an open wound or suffering from any skin disease or any other contagious disease should not come in contact with the milk. Any injury on hands or forearms must be covered with a water-resistant bandage.
He should possess a valid food handler certificate issued by Sanitary Authority
Effective washing of hands and arms with proper means; adequate clean water, soap, nail brush, and thereafter drying hands and arms with a clean cloth or disposable paper towel.
He should properly trim nails and must not wear ring or any other jewelry so as not to injure the udder or teats.
Neat appearance; wearing clean clothes, hair cap to cover hair.
Smoking is not permitted in areas for milking, and milk storage (FSA, 2006).
A good milking technique is essential for the production of safe raw milk. Cleaning of teats before milking is important to remove both visible soiling (e.g. feces, bedding, mud, residual post milking disinfectant) and bacteria which could contaminate the milk. Washing with water gives the cleanest udder, teat and flank. The water should be between 200C to 400C. Long hairs from the flank and udder should be removed regularly. The wet udder should be dried with paper towel which should be used only once to prevent the spread of bacteria and other pathogens to other cows. If paper towels are not available, sterilized cloth can be used but should be replaced regularly. Thorough washing and drying may be followed by treating with disinfectant (e.g. sodium hypochlorite solution or Dipal), an approved pre-dip solution which must be effectively removed before hand milking or cluster attachment. The use of predipping using iodine has demonstrated to reduce standard plate count and coliform counts in raw milk by five- and six-fold respectively as compared to other methods of premilking udder preparation (Galton et al, 1986). The overall reduction of microbial loads in raw milk through the use of predipping should result in reduced numbers of zoonotic pathogens. Predipping has been shown to reduce the risk of listeria monocytogenes in milk filters by almost four-fold (Ruegg, 2003).
Before the real milking can start each quarter should be inspected for physical/chemical/organoleptic abnormalities by checking the foremilk. The first milk should be spread on a dark surface, a foremilk cup or a dark tile. Abnormal milk shows discoloration, flakes, shreds, clots, blood spots and/or wateriness (Bonnier et al, 2004). If the milk shows such warning signs then the milk should be kept aside because of the risks to humans. The examination of milk must also be done before attaching milking units. Fore-milking assists early detection of mastitis removes potentially contaminated milk from the teat canal and stimulates milk let down. Cows with infected udder (mastitis) and those under treatment with antibiotics should be milked last and the contaminated milk disposed of properly (FSA, 2006).
After fore-milking the milker will be aware if milk quality is satisfactory or not. If milk is free from warning signs, milking of the healthy udder can carried out for human consumption. To milk the cow clean, dry hand must be used and the whole hand should be used instead of only thumb and forefinger because the latter grip is considered bad for udder health and flow rate (Bonnier et al, 2004).
Equipment used during milking
As soon as milk comes out from the udder it gets into contact with the surface of the recipient vessel for example bucket/pail or aluminium can. Surfaces are usually metal, stainless steel, tinned steel or plastic and they should all be kept in good hygienic conditions. Nowadays Stainless Steel is used as the material of construction for Dairy and Food processing equipments world over to achieve the most exact requirements for easy maintenance, sanitation, product preservation, corrosion resistance and to avoid health hazardous effects of aluminium and plastic (http://www.busiverse.com/dairyproducts). The design of milking equipment, where used, and cans, should ensure there are no crevices or recesses that can interfere with proper cleaning (CAC, 2004).
Chapter 3: Methodology
Data collection was done by carrying out a questionnaire based survey. The questionnaire assessed the various sanitary practices and perceptions on the dairy farms. Desk study of recent reports on cattle breeding sector was also conducted to get relevant information on the topic. Moreover key informants like the Agricultural Research Extension Unit situated at St Pierre and the Veterinary Service Division at Reduit were approached. An appointment was fixed through contacts by email and phone call. After interviewing the concerned party, an idea of the current situation as concerned the cattle breeding of the livestock sector was obtained. The names, contact numbers and addresses of the dairy cattle breeders around the island were obtained. Statistical data was obtained from the government website of central statistic division.
The study was based on questionnaire survey among the dairy cattle breeders. While designing the questionnaire, the data collected was considered. The survey covered both management practices used on the farm and it was also composed of questions regarding beliefs and opinions about selected dairy breeding farm issues. The questionnaire consisted of different parts namely the sanitary condition of the cowshed, Pre-milking practices, post milking practices, and animal health. The types of questions used were mainly close ended type and only a few open ended.
The sampling population was the dairy cattle breeders in Mauritius. It is obvious that the whole population cannot be surveyed, thus a total of 26 breeders were randomly selected using random numbers from a sampling frame that included addresses of all dairy cattle breeders registered by AREU. The her