Reproduction des vaches laitières :Economic indicators and impacts
In dairy farming, reproduction management strongly influences the productivity of the farm.
Indeed, animal reproduction involves two types of costs:
- The direct costs (apparent) = veterinary fees (curative and preventive), for example.
- The indirect costs (non-apparent) = renewal costs (fertility problems) and maintenance (net loss in case of unproductivity estimated at €2 to €3 per day per dairy cow), etc.
It can therefore have a significant economic impact, in the form of lost income as well as losses, and must be subject to a compromise according to the farmer's objectives and work organization.
Theoretical introduction
Fertility objective
In dairy farms, it is most often considered that the objective of fertility is 1 calf / cow / year, depending on the fertility which is the ability of a cow to reproduce or the number of inseminations needed to achieve or not a pregnancy.
Annual reproduction cycle
Knowing that a cow's gestation lasts about 275 days, the fertilizing insemination must therefore take place within the 3 months (90 days) following calving to achieve the fertility objective stated above.
During the first 30 days after calving, uterine involution occurs, that is the phase during which the uterus returns to its normal size. And even if during this period the first heats appear, fertilization is impossible. It is therefore necessary to wait for the next cycle (45-50 days) before hoping to inseminate the cow for the first time. To maintain a 365-day cycle, the fertilization time window is therefore 45 days. It is during this period that the heats of the animals must be monitored. This duration corresponds approximately to 2 ovarian cycles (21 +/- 2 days), so the farmer can detect up to 3 potential heat periods to meet his fertility objective.
Other fertility indicators
- CI : Calving Interval, considered optimal at 365 days for cows producing about 8,000 L of milk per year. It is generally longer for more productive animals: in 2019 in France, it was on average 421 days for prim'Holsteins with an average annual production of 8957 L / cow[1].
- CFI : Calving to Fertilizing Insemination Interval, for a CI of 365 days the CFI should ideally be less than 90 days (see previous paragraph), in the 2016-2017 campaign the national average was 136 days[2]
- CR : Conception rate, the pregnancy rate = number of pregnant cows over number of inseminated cows.
- NDR : Non-Return Rate, percentage of females not returning to heat 2 months after insemination, thus potentially pregnant.
- Nb AI/CFI : Number of Artificial Inseminations per Fertilizing Insemination, the average number of inseminations needed for a female to become pregnant, at herd level (national average all breeds combined = 1.99 in 2018-2019[3]).
To go further:
Consult the REPROSCOPE website, an online and freely accessible database for reproduction indicators from 2013 to 2019, click here.
Reproduction management in practice
Global context
Over the last decades, a global decline in fertility has been observed in dairy cows, particularly in the Holstein breed, the reasons cited being selection orientation[4] and the emergence of epizootics[5].
It is estimated that in Europe, the costs caused by a fertility drift can range between €15 and €34/cow/year[6], which can weigh heavily on farms with tight margins as well as those with large herds.
In France, animal insemination by the farmer, regulated since 2006[7], is an increasingly used practice [8].
In this context, it appears to be a key issue for farmers to take ownership of reproduction control indicators and/or to call on quality technical support.
Example of 195 Breton farms
From 25 February to 30 April 2021, a reproduction practices observatory was conducted by EILYPS (Livestock Advisory) on farms in the south of Ille-et-Vilaine (35), mostly composed of Prim'Holsteins (87%).
The objective was to characterize reproduction control through 3 indicators: the CI, the first AI success rate, and the average age at heifer calving.
Observations were made by interviewing dairy farmers face-to-face. Once extracted, these were analyzed and provided an overview of how reproduction is managed there. The general procedure was to ask farmers about their objectives regarding the 3 indicators, then compare these with actual average values from the database.
The observatory report is available here in PDF version.
Calving interval
Among the 195 farms surveyed, 157 (80%) had determined a "target CI" in their reproduction strategy.
On average, this average delay objective between two calvings was 400 days, with 2 main strategies emerging: around 400 days, and around 370 days (see graph 1). The data collected allowed calculation of the difference between actual and target CI in 104 of these farms, this difference is shown by the following curve:
In graph 2, the vertical red bar represents all responses for which the target CI is exactly equal to the actual CI. Values located to the right of this mark correspond to the situation target CI > actual CI, and those to the left of the mark: target CI < actual CI. It is therefore observed that 92% of farmers did not reach their target, and that on average the actual CI is 21 days longer than the target CI, which could generate an average net loss of €42 per cow (considering €2 / day of unproductivity / cow).
It is also interesting to note that among all 195 farms surveyed, only 115 (59%) were able to estimate an average CI in their herd. And the estimates collected were mostly underestimated values (7 days shorter than the actual CI on average).
First AI success rate
In the observatory, the same approach was applied to study the first Artificial Insemination success rate. As with CI, the majority (80%) of farmers surveyed declared having a target success rate, with again several strategic trends: a target at 50% (a quarter of responses), a target at 60% (a third of responses) and one at 70% (a fifth of responses).
The same calculation was made from Landfiles data to determine the difference between these targets and the actual success rate observed on average on the farms. Across the sample, an average difference of 17.4 points is observed (see graph 3.) : the average target rate being 59.1% and the average actual rate 41.7%.
As before, the red line indicates farms where the target success rate is equal to the average actual rate. In fact, the vast majority (98%) of farmers obtained an actual success rate lower than their target (values to the right of the red line).
If it is considered that losing one point on the first AI success rate causes a cost of €3, then on the sample an average loss of €51 per dairy cow can be estimated.
Age at heifer calving
Lowering the age at which heifers calve allows, among other things, to shorten the period during which they generate costs (feed etc.) without being "productive". Optimizing the costs related to this activity could save about €40 / month / heifer.
Indeed, the average objective of 188 farmers surveyed is to have their heifers calve at 25 months. Values were very tightly grouped around this value since 82% of responses gave a target between 23 and 26 months. In comparison, the average actual age calculated on the respondents' farms is 27 months: the potential loss is therefore €80 per heifer.
95% of farmers therefore did not reach the target value they had set.
Summary
Dairy cow reproduction must be reasoned by a delicate compromise between productivity, animal health and work management. It is increasingly taken in hand by farmers (21% of respondents involved in Farmer Insemination in the study presented), which implies a need for training and support. There are many indicators to manage it, but poor management can lead to the accumulation of losses that are difficult to detect in an accounting statement.
To go further
Consult the EILYPS website, a consulting and expertise company in livestock:
La technique est complémentaire des techniques suivantes
References
- ↑ Prim'holstein France, 2019 Dairy Control Results, 2020. https://primholstein.com/2020/resultats-2019-du-controle-laitier/
- ↑ F. Bidan, IDELE, Seen in Reproscope, Farm performances 2016-2017, The letter of the French cattle reproduction observatory - no. 2, 2018. https://idele.fr/en/detail-article/performances-en-elevages-2016-2017
- ↑ REPROSCOPE - National bovine reproduction observatory, accessed in January 2022. http://164.177.30.205/pentaho/api/repos/:public:reproscope:accueil_reproscope.wcdf/generatedContent?&userid=public_user&password=_Repr0sc0pe_Pu
- ↑ F. Mecheklour, REUSSIR Lait, Fertility rapidly deteriorates in Prim'Holstein, 2003. https://www.reussir.fr/lait/la-fertilite-se-degrade-rapidement-en-primholstein#:~:text=La%20moiti%C3%A9%20de%20la%20d%C3%A9gradation,la%20s%C3%A9lection%20dans%20cette%20race.&text=Les%20petites%20filles%20de%20ce,avoir%20une%20moins%20bonne%20fertilit%C3%A9.
- ↑ P. Le Mezec et al., Evolution of fertility and impact of BTV on reproduction of the French dairy herd, 2010. http://www.journees3r.fr/spip.php?article2996
- ↑ Dairy Production Technical Office, Web-Agri, How to measure reproduction results?, 2021. https://www.web-agri.fr/reproduction/article/203004/comment-mesurer-les-resultats-de-reproduction-
- ↑ Légifrance, Order of 28 December 2006 relating to the practice of insemination within the framework of public mating in bovine, ovine and caprine species. Current version as of January 21, 2022. https://www.legifrance.gouv.fr/loda/id/JORFTEXT000000821256/
- ↑ D. Scohy, Web-agri, More and more farmers are taking insemination into their own hands, 2019. https://wiki.tripleperformance.fr/index.php?title=Reproduction_des_bovins_lait_:_quels_objectifs_et_quelles_cons%C3%A9quences_%3F&veaction=edit
