Implementing selective dry cow therapy
The "selective dry cow therapy", or "selective drying-off" is a health management protocol for dairy cows during the drying-off period, aiming to optimize (reduce) the use of antibiotics.
This protocol is obligatorily implemented by a veterinarian, and not all farms are necessarily concerned: because certain health conditions must be observed beforehand.
Definitions and description
Principle and stakes of drying-off
Drying-off corresponds to the period during which a cow stops producing milk, generally about ten months after calving. Drying-off can then be strategic or spontaneous depending on whether the farmer chooses to stop milking (if the udder is no longer stimulated, milk production eventually stops) or if the secretory activity of the mammary gland exhausts itself.
The objective of a strategic drying-off is to allow a rest to the animal so that it rebuilds its fat and bone reserves, but also to prevent and eliminate mammary infections, thus ensuring good productivity for the next lactation. Consequently, it conditions the health of the cow and her calf at calving.
From an economic point of view, the choice of drying-off duration can have multiple consequences: shortening or prolonging the current lactation, productivity of the next lactation, and improvement of the animal's body condition score. In short, it is established that the health benefits, and sometimes economic benefits, of drying-off are optimal for a duration (often recommended) of 60 days.
This period is therefore the result of a compromise between productivity and health of the cows, at the crossroads between production and reproduction of the latter.
Selective drying-off
Conventionally, drying-off a group of producers involves a series of systematic care and antibiotic treatments. The goal of so-called selective drying-off is to categorize dried-off cows according to their risk of exposure to various infections, so as to refine and reduce this use of antibiotics. This practice is part of the fight against antibiotic resistance, coordinated notably by the Ecoantibio plan.
Methodology and conditions of application
The principle is to determine at the herd level and for each producing cow whether the health status of the animals and the environmental risk factors allow or not to reduce or even eliminate the use of antibiotics.
To know if such management is compatible with the functioning of the farm, two criteria are generally listed: the mammary health status of the herd animals, as well as their environment at the time of drying-off (housing, calving place ...).
Mammary health indicators
To assess the mammary health status of an animal at the end of lactation, one often refers to the somatic cell count in the milk of the animal. Indeed, to consider implementing selective drying-off this indicator can be studied:
- At the herd level, with the average cell count in the tank over the last 6 months (% tank cells).
- Then at the individual level, with the cell counts of each cow to be dried off, taking the value at drying-off as well as the average of the last 6 months (%SCC).
- Total absence of mastitis during the 3 months preceding drying-off.
For these two indicators, the thresholds are as follows:
- An average herd somatic cell count < 200,000 cells/L. (Selective drying-off can still be considered for a higher value, subject to tank analysis).
- Somatic cell count at the individual level < 100,000 cells/L for a primiparous, and <200,000 cells/L for a multiparous but subject to California Mastitis Test (CMT) on the day of drying-off and bacteriological analysis 7 days before.
- Total absence of mastitis during the 3 months preceding drying-off.
Environment and risk conditions
The second criterion to consider before resorting to a selective drying-off protocol is the immediate environment of the dairy cows during this dry period: where are they housed and where will they calve?
The diagram below lists a non-exhaustive list of conditions for which a health risk is estimated. If two or more risk factors are identified on the farm, then the use of selective drying-off is not recommended.
Summary
Selective drying-off refers to a set of measures to reduce antibiotic treatments during the dry period. Before these measures are deployed in a farm, it is imperative to ensure that the herd's health conditions and environmental risks allow it. In this way, a rational management of antibiotics is ensured without compromising the health and performance of the animals.
Further reading
Consult the website of EILYPS, a consulting and expertise company in farming:
https://breeder-connect.com/article/mettre-en-place-le-tarissement-selectif-des-vaches-laitieres
La technique est complémentaire des techniques suivantes
References
- ↑ F. Séreys, Produire mieux, Édition France Agricole, Le tarissement des vaches laitières, 1997. https://www.google.fr/books/edition/Le_tarissement_des_vaches_laiti%C3%A8res/dSonbGju-jgC?hl=fr&gbpv=1&printsec=frontcover
