Drying off, or halting milk production, is a common management practice in dairy animals. Typically, goats are brought into a dry period in which they produce no milk. This practice is done to improve milk production and control udder health issues such as intramammary infections (mastitis) before the animal’s next lactation. In 2013, then PhD candidate Gosia Zobel, and her supervisors Drs. Ken Leslie and Marina von Keyserlingk from the University of Guelph and the University of British Columbia, partnered with the Centre of Excellence for Goat Research (COE) and Innovation, Natural Science and Engineering and Research Council (NSERC) and Ontario Goat to examine how dry off impacts dairy does in Ontario.
Dry off
The average length of the dry period for Ontario dairy does is 50 to 60 days, but there is a significant range among farms, and even among does on the same farm. The reason for this variability is that some producers make dry off decisions based on days until kidding (for example, they always dry off a doe 60 days out from her expected kidding date) while others make dry off decisions based on milk production (for example, they only dry off does that are producing less than one litre of milk per day). The “Guide to Udder Health for Dairy Goats” recommends a dry period of 28 to 60 days to allow the doe’s udder to rest and prepare for kidding. In dairy cows, omitting the dry period can reduce milk produced in the next lactation by up to thirty per cent; interestingly, the 2013 COE study did not find this result for dairy goats. Nonetheless, drying off has other benefits. For instance, the dry period gives producers the opportunity to address any udder health issues (mastitis) before the doe begins milking again. The dry period should be long enough to ensure that no drug residue from dry doe treatments will be present in colostrum at kidding or when the doe enters the milking herd. As there are no drugs labelled for use in goats in Ontario, any drugs used are considered “off-label,” and you will need a prescription. Work with your veterinarian to develop a dry doe treatment protocol.
Reducing milking frequency and restricting or changing feed are the most common methods to reduce milk production ahead of dry off. Producers should be aware that abrupt changes to a routine and restricting feed intake can reduce welfare by causing stress and hunger. Restricted feed can also lead to diseases such as pregnancy toxemia and ketosis. Some producers restrict water to reduce milk production. This is not a recommended practice and has serious welfare concerns. Restricting water intake can lead to health problems such as dehydration, other health complications, or even death.
There is a large body of research that suggests performing any livestock management change should be done gradually, rather than abruptly, to reduce the impact on the animal. The way milking is ceased is important: in an experimental setting, Zobel et al. found dairy cows, when abruptly dried off but left in the same pen, are more likely to spend time waiting at the gate to the parlour. This may indicate pain, from a full udder, as well as frustration from the change in routine. Cows that were dried off by a series of skipped milking did not perform this behaviour. Of further interest, the cows that were abruptly dried off also experienced more milk leakage, a risk factor for mastitis.
More research is needed to determine how different dry off strategies impact productivity and welfare of dairy goats. However, milking once per day for several days before dry off will help reduce milk production, especially in does that are hard to dry off.
Dry doe treatment
It is important to note that preliminary research suggests that the dry period is a key time for mastitis to occur. It has been shown that the use of a dry period mastitis treatment product can prevent and cure infections in dairy goats. However, the majority of Ontario producers do not use such treatment at dry off. This likely stems from difficulty in infection identification and therefore a low perceived prevalence. Indeed, when surveyed as part of the 2013 COE study, over half of the respondents indicated minimal to no concern regarding subclinical mastitis. When does were sampled on a subset of these farms, 40 per cent of them entered the dry period with a subclinical infection. When the does kidded, 49 per cent had an infection in at least one half of the udder. The impact these infections have on the animal is dependent on the bacteria, with many showing no symptoms or only minor increases in somatic cell count, but some cases can be severe, significantly decreasing milk production and even causing death. The prevalence of infections found around the dry period indicate that dairy goat producers may need to reconsider their level of concern. While not always easy to identify, infections around kidding are likely higher on most farms than perceived. Discussion with the herd veterinarian can identify simple changes that can improve udder health, such as ensuring does are lower in milk production, and fully milked out and teat dipped prior to dry off, or improving dry doe housing to be dry and clean.
Preventative treatment for mastitis can be done selectively, only administering treatment to does that have been identified as having past issues with mastitis, preferably by using a CMT (California Mastitis Test) prior to dry off. Producers can also use blanket treatment, where every doe is treated at dry off. Selective treatment reduces the cost of treatment and prevents unnecessary antimicrobial use. Producers using selective treatment should have a low prevalence of mastitis and good control of environmental management of mastitis (for example maintaining clean, dry bedding). In cows, selective treatment method is gaining popularity as the livestock sector experiences pressure from human health agencies to reduce antimicrobial use to help prevent antimicrobial resistance. Blanket treatment is often used in herds with a high prevalence of infection and somatic cell counts. This method is more expensive, but is an established method of reducing udder health issues in the next lactation in dairy cows, ultimately saving money in treatment costs and loss of milk. However, in dairy goats, there is not enough research to prove this is the best way to reduce mastitis. Producers are recommended to talk to their herd veterinarian about appropriate treatment and management protocols to manage subclinical mastitis.
Extended lactation
Extending lactation beyond the usual 305 days can reduce the number of dry months and the number of kiddings over the life of a doe. Extended lactations with a longer kidding interval protect does from some of the health and welfare concerns around dry off and kidding, such as mastitis, pregnancy toxemia and ketosis. However, longer lactations do result in fewer kids being born, as well as plateaued lactation curves. Therefore, it is important for individual producers to be aware that such management requires a balance to be sought betw
een reduced treatment costs and improved longevity of does, and the potential loss of profits from lower milk production and kid sales. However, overseas literature demonstrates that with feeding regimes focused on milk production, and selecting high producing animals, does can maintain production levels upwards of three to four litres per day for well past the traditional lactation length. As an alternative method to extended lactation (where the doe is not mated), some producers also practice skipped dry periods (where the doe is mated, but not given a dry period). While evidence in dairy cows has found calving without a dry period results in lower milk production in the next lactation, the 2013 COE study did not make this link. In fact, does with shortened or skipped lactations had less metabolic issues and did not have reduced milk production in the first two weeks of lactation. A cautionary point with skipping the dry period is that colostrum quality is likely to be reduced, and therefore producers feeding dam colostrum to the kids should be aware that supplementation may be needed.
An added benefit of continuing to milk does past standard annual lactation lengths is that this practice encourages animals to dry off at a lower production level. This production level more closely resembles the level at which a kid would be naturally weaned, in turn this prevents some of the health and welfare concerns associated with drying off high producing does. Producers considering extending lactations or skipping dry periods should work with their herd veterinarian to determine if such management is suitable for the specific herd.
Summary
The traditional perspective towards dry periods in dairy cows is that they are required to increase the amount of milk produced in the next lactation. Downtime from milking is also a key period to address udder health issues. While these facts remain largely relevant for dairy goats, it is important to consider that this information has stemmed from dairy cow literature. The science behind dry period management in dairy goats is still developing. Ontario’s dairy goat producers are in a unique position to add to this development. The recent COE study demonstrated that while producers in Ontario do aim to dry off their goats, many practice alternative management practices like extended lactation lengths and continued milking within an annual mating cycle. This flexibility in management stems from many producers focusing attention on the needs of individual goats.
If you are interested in improving your lactation and dry off management, talk with your herd veterinarian to find a management scheme that works best for you and your does.
This project was funded in part through Growing Forward 2 (GF2), a federal-provincial-territorial initiative. The Agricultural Adaptation Council assists in the delivery of GF2 in Ontario.
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The statistics about management practices in Ontario dairy goats in this issue of the Goat Gazette are from a study that combined a survey of all of Ontario dairy goat milk producers with intensive on-farm measurements in 2013 by Zobel, G., Leslie, K., and von Keyserlingk, M.
Dr. Gosia Zobel is currently based at AgResearch Limited in Hamilton, New Zealand, where she continuing dairy goat welfare work. She can be reached at gosia.zobel@agresearch.co.nz.
For more information about dairy goat udder health, order a copy of the new Udder Health Manual. To order your copy of the Udder Health Manual please contact Ontario Goat at 1-866-311-6422 or info@livestockalliance.ca. The price for the manual is $45 ($15 for licensed Ontario dairy goat producers). The price includes shipping within Ontario.