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Guide to udder health released for dairy goats

Paula Menzies for Progressive Dairyman Published on 31 December 2018

The detection and control of clinical and subclinical mastitis in dairy goats is critical for the production of healthy milk for human consumption. Dairy goat producers want to produce the highest-quality product – specifically, milk – for their consumers.

Part of the process of achieving this goal is to maintain the health of the animals that produce that milk and, in particular, the health of the udder.

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To facilitate this, we wrote a guide designed to help educate producers, veterinarians, and extension and dairy support personnel on how best to do that.

This project was funded by the University of Guelph – Ontario Ministry of Agriculture Food and Rural Affairs (OMAFRA) Partnership – Knowledge Translation and Transfer program, along with the help of many veterinarians and producers who beta-tested the guide for us.

The information in this guide has come from a number of sources but includes extension information from both the small-ruminant and cow sectors, and new information from the latest research from around the world. It is available for download at the International Goat Association website.

Quality milk is defined by its characteristics: level of bacteria, somatic cell counts, freezing point, residues of veterinary drugs, other chemicals and toxins, and by its colour, flavour and odour. Udder health refers to measures to keep the udder and the doe healthy, so it can produce high-quality milk. Mastitis is the number one reason for poor udder health and is defined as inflammation of the udder.

The guide is divided into eight sections that will be reviewed briefly here:

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Section I – Normal lactation

This section reviews the normal anatomy of the udder and teat, and the physiology of milk production, including how various hormones work to initiate lactation, dry-off and milk letdown. Milk is produced by apocrine secretion in goats, different from cows. Non-disease factors that affect milk production are reviewed.

Section II – Mastitis: What causes it and how it is detected

The costs associated with mastitis are reviewed in this section in terms of economic impact, welfare costs and public health risk, and compared to the costs of an udder health program. The causes of mastitis are detailed, in particular important contagious and environmental organisms, and the risk factors that increase the likelihood of mastitis developing in a goat are reviewed.

How mastitis is detected in a gland or udder is covered with particular attention to detection and interpretation of somatic cell counts (SCCs) either from an SCC counter or from the use of a California Mastitis Test. How to properly take a milk sample for culture and how to interpret the results is included.

Section III – Milking management

This section assists the producer in applying correct procedures for milking the goat, including udder preparation, milk-out time and teat dipping. The risks of overmilking, dirty udders and teat trauma, and how to avoid this are highlighted. Proper management of the doe post-milking to reduce risk of mastitis is discussed.

Section IV – Proper maintenance and use of milking equipment

How goats are milked in different systems, including types of parlours and entrances and exits, as well as hand-milking, is covered. Care of the equipment is dealt with in detail. This includes the basics of cleaning milking equipment and containers and types of residual films on the milking equipment.

Routine setup and inspection of milking equipment, as it pertains to dairy goats, is covered in depth. Values for pulsation, vacuum, etc., are taken from recommendations by the International Dairy Federation. Expected maintenance schedules for equipment and parts are reviewed. How equipment should be inspected and what may signal a potential issue is listed.

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Section V – Milk quality

Although the guide is not regulatory in nature, the requirements for Grade A goat milk at pick-up in Ontario are covered. Bacterial numbers should be less than 321,000 individual bacteria cells (Bactoscan) or 50,000 bacteria per millilitre milk (standard plate count). This section helps the producer troubleshoot causes when milk quality fails the regulations.

This includes parlour, bucket milking and hand milking systems. The role of mastitis in causing elevated bacterial counts is discussed. SCCs must be less than 1.5 million cells per millilitre milk, although the causes of elevated SCCs are discussed in Section II. Freezing point, detecting inhibitors (i.e., antibiotics, disinfectants) and bad flavours and odours are also discussed. Many additional articles are available on the OMAFRA website.

Section VI – Treatment and control of mastitis in dairy goats

This section first discusses veterinary drug use in lactating dairy goats – in Canada, there are no approved drugs for goats. To properly manage this issue, there is much discussion on how to detect drugs in milk and how to establish an appropriate science-based withdrawal with your veterinarian.

The difference between how antibiotics are detected in the milk using on-farm test kits versus regulatory laboratory-based testing is reviewed. To properly use drugs in an extra-label manner, it is critical to have a valid veterinary-client-patient relationship (VCPR) and all drug use be by veterinary prescription.

Treated animals must be permanently identified and communicated with the milker. Good records are critical to preventing treated animals from being accidently milked into the tank. All drugs must be properly labeled and stored. Administration technique to the goat must be done using the correct route and location of administration and in a sterile manner; use of intramammary preparations is discussed in depth.

Approaches to treatment of clinical and subclinical mastitis in lactating goats are discussed, along with pros and cons. Treatment at dry-off is most commonly done in dairy cows, but much less is known how this is best done in dairy goats.

Management of specific types of pathogens is discussed, specifically caprine arthritis encephalitis, environmental pathogens and Staphylococcus aureus. The latter is covered in most depth, as this is the most important cause of clinical mastitis in goats.

Section VII – Monitoring and goal-setting

While recordkeeping is critical to udder health, its true value is only apparent when records are analyzed and goals are set – along with an action plan to achieve those goals. The SMART (specific, measurable, attainable, realistic and timely) approach to goal-setting is reviewed. The following parameters can be used to monitor udder health:

  • Incidence of clinical mastitis events/lactation

  • Proportion of does with elevated SCC levels or changes indicating a new case or a chronic infection

  • Animal losses due to mastitis: culling, death due to mastitis

  • Measures of milk quality such as Bactoscan levels

Section VIII – Dairy goat health management

This last section gives a brief overview of other areas of herd health important to keep the dairy doe healthy. Proper management of the dairy doe during the transition period requires attention to many issues. Proper vaccination against clostridial diseases is addressed.

Abortion diseases are common in dairy goats; this section addresses the more common types and how to investigate the causes and protect humans working with goats. Late-gestation and early-lactation nutrition is addressed, including feed and water quality, necessary vitamins and minerals, and control of common nutritional and metabolic diseases.

Kidding time is a particular risk for both the doe and her kids. Kid health and prevention of common chronic wasting diseases is reviewed, including colostrum management. Housing of dairy does and how housing may affect milk quality is reviewed.

Reproductive management to ensure year-round milk is explored. Important infectious diseases of adults and youngstock are touched on, including internal and external parasites, chronic wasting diseases. Principles of biosecurity are reviewed to assist with control of infectious diseases.

Because so many aspects of keeping the udder healthy rely on a VCPR and an excellent relationship with the herd veterinarian, a section on “finding a veterinarian” assists producers on how they may locate a suitable veterinarian in their area.

Summary

This guide provides an overview of udder health for dairy goats. While there are similarities to dairy cows, there are many important differences. Its intent is to provide sufficient information for producers, their veterinarians and support personnel to investigate deficiencies and come up with good solutions to improve the health of the goat and its udder.  end mark

Authors of the guide, in addition to Paula Menzies, are Jocelyn Jansen, Animal Health and Welfare, Ontario Ministry of Agriculture Food and Rural Affairs; Michael Foran and Philip Wilman, Dairy Food Safety Program, Ontario Ministry of Agriculture Food and Rural Affairs, Guelph, Ontario; Colleen Fitzpatrick, University of Saskatchewan, Saskatoon, Saskatchewan.

Paula Menzies is a Professor in the Department of Population Medicine at Ontario Veterinary College, University of Guelph.

Save the date

Dairy goat producers may be interested in attending the
Ontario Small Ruminant Veterinary Conference 
June 17-19, 2019
Guelph, Ontario

 

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