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2015-R1 Longevity dairy cows

2018-8-14 15:01:56 Comments:0 Views:354 category:Project Introduction

Research on Cow Longevity and Primary Reasons for Culling in China Dairy Farm with more than 100 Cows

4.1 About Principle Investigator


Short Curriculum Vitae

Education & work experience

Jun. 2011-Present    Associate Professor

College of Animal Science and Technology, China Agricultural University

Mar. 2010-May 2011       Visiting Associate Professor

Department of Animal Science, Cornell University, USA

Jan. 2010-Feb. 2010         Associate Professor

College of Animal Science and Technology, China Agricultural University

Jul. 2007-Dec. 2009 Assistant Professor

College of Animal Science and Technology, China Agricultural University

Sept. 20016-Oct. 2006     Visiting Scholar

Department of Dairy Science, University of Wisconsin-Madison. USA

Jun2006-Sept 2006 Exchange Student

Dairy Science Department, South Dakota State University. USA

Oct. 2002-Mar. 2006        Research Assistant

College of Animal Science and Technology, China Agricultural University

 

Field of expertise

Nutrition and Management in calves and heifers, Starch digestibility in lactating cows, Farm Management, Forage evaluation

 

Scientific publications are available at:

Http://cast1.cau.edu.cn/art/2015/8/11/art_19148_389853.html



4.2 Background and objectives of the study:


Recently, cow longevity attracted more attention in dairy industry in the world. More and more researchers try to find the correlations between risk factors and cow longevity, culling rate, from several aspects, such as genetic, breeding, reproduction, nutrition and farm management are related to cow longevity, in order to develop corresponding improvement and adversely affecting the cow longevity and farms’ profit. Compared with 2014, the number of dairy cows in China fell by 1.3 million, 8.7%, which is the greatest reduce in a decade. Compared with developed countries, the statistic of cow longevity and culling is still in blank stage in China. There were some researches related just focusing on some specific farm or district, which were hardly to show the real situation in china dairy industry. This research was aimed to show the real situation of cow longevity in china dairy farm and primary culling reasons.

Through farm visiting and questionnaire collecting, this research altogether collected data of 355,000 cows from 100 farms in total, from Northeast China (Heilongjiang), North China (Beijing, Hebei, Tianjin, Inner Mongolia, Shanxi), East China (Shanghai, Anhui, Shandong), Northwest China(Ningxia) and parts of the South of China (Guangdong, Hubei), eliminated from 2013 to 2015, which can represent 909,000 cows, 10.4% of all cows in China.
Objective:
1. The general situation of cow longevity in China dairy farms with more than 100 cows
2. Analyse the main culling reasons and risk factors
3. Practical recommendations for farm


4.3 Main report of the research

4.3.1 General situation of cow longevity

Table 4-1 shows the general situation of farms in survey and culling rate of culling cows. From 2013 to 2015, the average herd size is increasing, which reflected the process of china dairy farms from small farmers to large-scale farms. The average culling rate in 2014 is the lowest and the percentage of 2015 is highest, about 30.4%.

Table 4-2 shows that the average lifespan, the average productive lifetime and the average parity all increased year by year. That may related to the increasing proportion of large scale dairy farms. The unified management of high level is beneficial to the improvement of the cow longevity.

Figure 4-1 shows that less than 10% of farms have longevity more than 6 years. In 2013, 2014 and 2015, the proportions of these good performance farms are 9.0%, 5.4% and 5.5%, respectively. While more than 15% of farms have a longevity less than 4.5 years and the proportions in three years are28.4%,21.6% and 15.1%.


Combine figure 4-1 and figure 4-2, we found that most farm have a longevity between 4.5 and 6, but the average lifespan of most culls are lower than 4 years and higher than 6 years. In addition, it can be observed visually that as time, the average lifespan of farms became longer and the distribution of culls was changed. Compared with 16.4% farms in 2013, only 5.5% farms’ average lifespan was lower than 4. The proportion of farms with average lifespan over 5 years increased from 35.8% (2013) to 54.8% (2015). About 38.3% of culls lived shorter than 4 years in 2013 while the proportion declined to 29.8%. The proportion of culls lived longer than 6 increased from 19.1% (2013) to 28.6% (2015).


In figure 4-3 and 4-4, 71.9% farms located in the range of 4.5-6 years and only 31.7% culls located in the same range, which means more culls left herd before 4.5 in the other 29.1% farms.

These 4 figures show quite some potential to improve cow longevity in China, and apparently indicate the improvement in China cow longevity. As time goes by, farmers and farm managers started to pay more attention to cow longevity and make some improvement on it to reduce culling in lower parity.

According to the parity record and herd size of 90485 culls in the survey farms, the average parity is 2.7. Figure 4-5 shows 72% culls were culled in the first 3 parities and the proportion of the 2nd parity is the highest, about 26.2%. Observing the distribution in 2013, 2014 and 2015, the most culls all happened in the 2nd parity, but the proportions of the first and second parity were declined. Compared with 2013 and 2014, culls left the herd after parity 4 increased apparently. The proportion of culling in the first three parities is 76.5%, 72.5% and 68.3%, respectively in three years, which shows a declining trend.


*Data of distribution of 90485culls across parity classes in three years

There are many reasons for the high culling rate of the 1st parity cows. Firstly, the age of first service is too early. Secondly, the feed of fresh cow is over nutrition,which made the calve so big that hurt the birth canal. The high culling rate in early parity cows also reflects the management problems in feeding, breeding and diseases prevention. But the data also shows that the situation is becoming better.

4.3.2 Main culling reasons
Culling reasons of dairy cows divided by involuntarily and voluntarily culling reasons and most involuntarily culling due to reproduction problems and health disorders. There are kinds of diseases of dairy cow, in this research we divided all the disease into 7 parts, digestive disorder, udder disease, respiratory system disease, hoof disease, cycle system disease and nerve system disease. And the voluntarily culling divided into low production, sale and other (including old, bad body condition, bad temperament, et al.).
Figure 4-6 shows that more than 74% culls left the herds due to health diseases or reproduction problems. Among these culling reasons, the most-frequent primary culling reasons were “Repro”(infertility or reproduction problems), “Diges” (digestive system disorders and metabolic disorders), and “Udder” (udder-related disorders, such as mastitis and teat injuries), which accounted, respectively, for 20.9%, 20.7% and 13.7% of total culls. Hoof diseases was also important, accounted for 8.5%.
However, a larger percentage of cows (8.4%) were removed from the herd due to “Uno” (unknown or unspecified) culling reasons. This may indicate missing data recording in cow files, particularly in some farms in China. There have been studies trying to ascertain why cows die on farm and from which diseases, but the information gathering is hindered by inaccurate and inconsistent data entry.
In addition, only 11.4% were voluntarily culled cows and the highest voluntary or “selected” reason for culling is “Low Pro” (Low milk production) at 8.6%. That might show us farmers hardly cull their cows, unless the cows can’t bring benefits any more.



4.3.3 Culling reasons in different lactating days
There have been many studies suggested that culling rate for cows in earlier lactating days is very high. Figure 4-7 shows that about 27% culling cows culled before the first 60 days in lactating and the proportion is highest. Feed changing, calving and group turning are all stress for transition cows. If there are problems in these cows, the culling rate for cows in earlier lactating days will be always high. Culling also often occurs after 450 days in lactating days. In this stage, the main reason of culling is reproduction problems.

The figure 4-8 to figure 4-11 shows the distribution of culls across DIM classes in different culling reasons.
Figure 4-8 shows that more than 60% of culling cows removed by reproduction problems left herd after 350 days in milking. And 11.9% of cows with reproduction problems were removed before 60 days in milking.


Figure 4-9 shows that 35.5% cows with digestive diseases culled before 60 days in milking and 19.1% culled after 350d. While 68% cows with metabolic diseases culled before 60 days in milking and 15.7% culled after 350d. Metabolic diseases always happened before 60 days in milking, which might due to the changing ration after calving and kinds of stress.

Udder diseases are influenced by many factors, including the environment in barn and milking parlor, milking equipment and hygiene management, and operation of milking and dry milk program, etc. Figure 4-10 shows that most cows were eliminated within 180 days after calving, especially within 60 days, which may be due to problems in dry milk program and dry milk period management.


Figure 4-11 shows that 27.9% cows with hoof diseases culled before 60 days in milking and 15.1% culled after 350 days. Hoof diseases affected by various factors, physical factors such as the hard ground, uncomfortable bed, biological factors such as manure pile, disinfection not in time, and management factors such as unreasonable diet, trimming not in time, will lead to cows’ hoof disease.

 

4.3.4 Culling reasons in different parities




Figure 4-12 shows that in each parity level, the main culling reasons are still reproduction problems, digestive system diseases and udder diseases and hoof diseases. However, in cows culled after parity 6, 21.8% of culls due to voluntary reasons and the low milk production accounted for 13.7%. The proportion of low production and other voluntary culling reasons both increased gradually as the parity rise. By contrast, in the first parity, up to 28.4% due to reproduction problems were culled, which was 7.5% more than the proportion of reproduction reasons in all culling reasons in the whole group. As the parity rise, the proportion of culls with reproduction problems gradually reduced. In addition, the proportion of culls by the digestive and metabolic diseases, udder diseases and hoof diseases was highest in the 4 to 6 parity, more than 50%. While in the first parity, the proportion of cows eliminated due to the three categories of culling reasons was less than 35%.


4.3.5 Culling reasons in different milk production



All culling cows divided into three average milk yield levels, respectively are low yield (< 10.4 kg/day), middle (10.4 kg/day - 22.5 kg/day), and high yield (> 22.5 kg/day).

Figure 4-13 shows that no matter the milk yield in high or low level, reproduction problems, digestive and metabolic diseases and udder diseases are still the main culling reasons. But in low milk yield level, cow culled by more digestive and metabolic diseases, while in middle level, the proportion of reproductive problems obviously increased.

In the high milk yield level, ratio of culls with udder diseases was the highest and the ratios of culls due to hoof diseases, emergency and urgency, low milk production are obviously increased.

Though the milk production of this part of the cows was in the medium level in the herd, but the udder diseases and hoof diseases is likely to require using antibiotics in the treatment process, which not only affects the normal milking, the milk is also can not for sale. For the farmers or managers, these cows don’t have economic value, so they will be selectively eliminated. In addition, once the milk yield of high productive dairy cows decrease, even if there is no obvious symptom, they were also more likely to be culled.


4.3.6 Recommendations

In China, there is almost no attention to cow longevity. Farmers and farm managers are prone to put all their reflection and energy on how to make profits from cows and how to reach milk production targets. So the first thing we may do is communicating farmers and farm managers the importance of increasing longevity of cows.

Surveys show that the major reasons for culling are reproduction failure, mastitis, and lameness. Our data also show the similar conclusion that reproduction disorders, udder-related disorders, digestive system disorders and hoof diseases are assured known causes of culling in China, accounting for 68% of all culls. For most average herds these are the areas requiring attention to improve herd longevity.

Before, we have mentioned that milk production influences farm managers’ decisions. In fact, milk production is intimately connected to fertility and udder health. Hoof health and rumen health will also indirectly affect milk production. If a cow does not breed back and calve again, she will gradually (or suddenly) drop in production to levels beneath profitability. A mastitis cow produces less milk, if subclinical, or goes into the hospital group and incurs additional medical treatment and labor costs if clinical. Severe or chronic infections are costly.

If we want to increase cow longevity, we should improve the health and welfare of dairy cattle and minimize kinds of diseases of our cows.

The first step in improving longevity within a herd is to establish the current position by benchmarking key figures for the herd against group averages. Once a factor has been measured, it can be managed and priority areas can be identified for attention. Prepare a list of all culled cows in the last year. For each one identify the reason for leaving from the list. Then calculate some following indexes, such as:

1. Culling rate

Take the total number of culls over the 12-month period and divide by the rolling average herd size for the same period.

2.The percentages leaving for each of the main culling reasons

Calculated by taking the totals for each reason divided by the total number of culls.

3. Average lactation age (average parity)

Calculated using the latest set of records for the herd.

4. Involuntary or forced culling rate

The total number of culling cows for an involuntary reason divided by the rolling average herd size.

Using the calculated figures for the herd and comparing data with group averages, a farmer will find the relative situation. If this relative position is suboptimal, then he  can select a herd strategy to achieve his optimal position (reduce overall culling rate or reduce the level of a specific reason). All the problems cannot be fixed at once. So we should draw up a priority action list and address the biggest problems first.

Identify the major reasons cows are getting culled and generate possible solutions. If all culling reasons are higher than expectation, start from focusing on one or two to determine causes and begin action plans to correct the problems. Further investigation is needed once a category has been selected to better understand reasons for culling and generate possible solutions.In addition, if the total involuntary culling rate is greater than average or the farm target, or the involuntary culls are over 65% of all culls, there is opportunity to improve it. We can set an achievable guideline. However, the goal should be to minimize the involuntary cull rate.

For example, cows leaving the herd when less than 30 days in milk (DIM) usually are cows that have died or have serious metabolic or infectious disease problems at calving. It is important to distinguish between cows that are culled and cows that die. Analyse the records to determine early lactation culling cows and the broad categories causing cows to leave.The farmer should develop guidelines to support decisions about culling, especially for decisions in early stage of lactation. Farms also need todevelop a farm specific action plan and set up a monitoring plan. Work with the appropriate team of advisors and employees to develop an action plan based on your on-farm investigations and also some key monitors to determine if your plan is working. Make modifications to the plan if it does not deliver the expected results.

Many researches were about the main risk factors for involuntarily culling reasons and built economic models. However, how to let producers approved to accept the knowledge through the best management to improve the cow health and welfare is still an ongoing challenge.We called for the establishment of a clear standard of animal welfare and clear standards of digital, allowing farmers to clear what is their management level, in order to help them overcome these challenges.


4.4 Conclusion

1.The average yearly culling rate of China dairy cows in herds with more than 100 cows was calculated, which were 24.7%, 22.9% and 30.4%, respectively from 2013 to 2015. The average lifespan was accounted for 1616d、1749 and 1829d, while the productive lifetime was accounted for 747d、847d and 916d, respectively. The average parity at culling were about 2.5, 2.7, and 2.9.

In these 3 years, Dairy farming in our country is still in the transition to a intensive large-scale dairy farm, with the average herd size increasing and the ratio of farms with more than 100 cows increasing. Therefore, China dairy farms are equivalent to keeping expanding the scale. In addition, the farm operators and managers also gradually realized the importance of the cow longevity.In the daily management,they consciously to improve cow welfare and health, so the research data shows that the cow longevity was increasing year by year.At the same time, the increasing also reflects greatly improving space and potential in China dairy cow longevity.

2. Reproductive problems is the most serious accounted for 20.9% of the total number of obsolete, followed by digestive diseases, accounting for 20.7%, udder diseases (13.7%), hoof diseases (8.5%) and unknown reason (8.4%).

More than 74% of culls were culled because of kinds of diseases or reproduction problems.The voluntary culling proportionwas much less than other countries, accounted for 11.4%. And the highest voluntary or “selected” reason for culling is Low milk production at 8.6%, which might reflect that farmers always focus on profit and milk production. In addition,a larger percentage of cows (8.4%) were removed from the herd due to unknown or unspecifiedculling reasons, which indicate the omissions and contempt of data recording in China dairy farms.

3. Most Culling occurs before 60 days or after 450 days in milking, which ratio is about 27% and 22.6% respectively. Cows with reproduction problems and respiratory system diseases usually culled at early parities (1-3 parity), while cows with digestive system disorders, metabolic diseases, hoof diseases and udder diseases often culled at peak lactations (3-6 parity). More cows with reproductionproblems and digestivesystem disorders were low production cows while cows with high milk production often culled by udder diseases and hoof diseases. Therefore, farm shouldfocus on strengthening the management of transition cows, pay attention to the cow welfare, in order to reducing involuntary culling proportion.

 

4.5 Appendix

Longevity and culling rate: how to improve?

Proposed authors: Jelle Zijlstra*, Ma Jiayang**, Cao Zhijun** and Bennie van der Fels*

* Wageningen UR Livestock Research, Wageningen

** China Agricultural University, Beijing


4.5.1 The importance of longevity and culling rate

Animal health problems in dairy herds create extra costs, reduce milk production and will lead to high involuntary culling rates. In the Netherlands as well as in China dairy experts consider disease incidence rates and suboptimal culling rates as indicators of bottlenecks in dairy farm management. Improving health and animal welfare will result in longer living cows and this is why high longevity and lifetime production are seen as indicators for good dairy farm management. Improvement of this longevity is associated with lower culling rates.

Health problems are not only causing loss of profit but also disturb the workflow on the farm. Sick cows have to be treated and need extra attention until recovery. They will also cause infectious risks for the rest of the herd and should therefore be kept in isolation to avoid contamination.

The vision of farmers and consultants on longevity and culling is strongly influenced by views within the dairy industry and by the state of knowledge on animal health within the sector. These points are the reason that both topics evoke different associations in China and in the Netherlands. Table 4-1 lists some of these cultural differences.




The Netherlands have a long tradition in aiming at high lifetime production of cows. For many decades cows that pass the limit of 100,000 kg milk or 10,000 kg fat and protein are honoured at a party on the farm. And of course the farmer who cared for the cow, is part of this tribute. In the last five years longevity receives extra attention from society because it is seen as an indicator of good care for cows. This is why the dairy sector is now aiming at increasing longevity by half a year during the period until 2020. This goal is part of the sustainability program of the united Dutch dairy companies and dairy farmer unions.

The goal of this paper is to present the results and experiences of collaborative work on longevity and culling rate on dairy farms. In 2015 Wageningen UR Livestock Research and China Agricultural University investigated the present situation on longevity and culling in both countries. Wageningen UR livestock Research summarized the efforts done in the Netherlands to come to an improvement program on longevity. China Agricultural University collected data of 81 farms with 113,367 dairy cows aiming at getting a better insight into culling practices on Chinese dairy farms.


4.5.2 Present situation in the Netherlands

The average age at culling (also defined as longevity) of Dutch dairy cows is 5.8 years. In the last five years this figure has been quite stable. As mentioned before the Dutch dairy sector has the ambitious goal to increase it by six months in the period until 2020. Research showed that there is much variation between farms for this trait. The 25% farms with highest longevity have an average longevity of 7.1 years, whilst the 25% farms with lowest longevity have an average longevity of 4.9 years. This variation shows quite some potential to improve longevity.


Figure 4-14 shows the division of culls by parity for Dutch cows on farms where culling reasons were recorded. The proportion of herds that record culling reasons has steadily grown in the last decade. In 2012 it was increased until 32% of all farms participating. The pattern shown by the bars in figure 2 is strongly connected to longevity. If longevity increases, a larger part of the culls will take place in higher parity numbers.

Figure 4-15 shows the reasons for culling on Dutch farms. Fertility, cell count/mastitis and legs and claws are the most frequently mentioned reasons for culling. The fourth reason ‘fattening’ is a kind of indirect reason for culling. Farmers will usually only fatten cows if they have decided to cull the cow at a later stage but like to combine milk production with fattening in the remaining productive life of the cow. The underlying reason for this decision can be e.g. infertility or disease incidences. Fattening is a kind of voluntary culling with an involuntary underlying reason. The same can be more or less true for other voluntary culling reasons like excess cows, low production and old age. This combined voluntary and involuntary culling reasons show that the differences between these two main categories are not easy to mark. However, Figure 4-16 shows very clearly that that fertility, mastitis, claws and miscellaneous health problems are the main reasons for involuntary culling on Dutch farms.



4.5.3 Present situation in China

As mentioned before China Agricultural University collected data from 81 farms with 113,253 dairy cows (including dry and lactating cows) in total. The average herd size of these farms was 1398 cows.

Actually, the study comprised two main parts:

1) Individual cull information (farm visits and questionnaire)

2) Group dairy farm data

Firstly, participating dairy farms noted the reasons for culling of every cow that left the herd over a twelve-month period, starting in 2013. Secondly, these culling records provided primary culling reasons for each cow leaving the herd, resulting in a list of 50 culling reasons. Thirdly, each participating herd was sent a questionnaire asking for specific and detailed information on the management system of their herd. The questionnaire asked for details about the herd management system including fertility management, herd replacements, housing, milking, labour, and nutritional aspects. Table 4-2 shows a summary of the general statistics of the participating farms.


Among these farms, 31 farms have lower culling rate than 23.3%. 76 of the farms recorded the parity of 25,917 culled cows and 65 farms recorded both the birth date and cull date for 23,881 cows. The average lifespan of culls is 4.9 years and the average productive life of these dairy cows is 2.7 years. Among the 65 farms, the 25% best performing farms have an average longevity of 5.6 years, while the 25% worst performing farms have an averaged longevity of 4.0 years. 
Figure 4-17 shows that 6.2% of the 65 farms have a longevity of more than 6 years, while the cow longevity in 16.9% of these farms is lower than 4.5 years. 49.2% of the farms have a longevity of less than 5 years in figure 4-17, while figure 4-18 shows that more than 57% of culling cows leave the herd before they reach the age of 5 years old. This difference is caused by the larger average herd size of the farms in the two low longevity classes in figure 4-17. However, 22.5% of culling cows leave the herd after 6 years old.
In figure 4-19, the annual variation in the percentage of culling cows shows that more cows leave the herd after 6 years old and less cows were culled before the age of 4.5.
Figures 4-17 and 4-18 both show quite some potential to improve cow longevity in China, while figure 4-19, apparently, indicate the improvement in China cow longevity.



Figure 4-20 shows the distribution of 26,341 culls by parity and there were 514 culling cows with no parity recording. And figure 4-21 shows that among the 25,917 culled cows, more than 73% of them are culled in the first 3 lactations and the highest percentage of cullings is in parity 2 with 26.3% of all cullings. This division of cullings about parity leads to an average parity of culling of 2.7.

The most-frequent primary culling reasons were “Diges” (digestive system disorders and metabolic disorders), “Repro” (infertility or reproduction problems), and “Udder” (udder-related disorders, such as mastitis and teat injuries), which accounted, respectively, for 23.9%, 22.7% and 12.9% of total cullings. More than 81% of the cullings were declared in relation to health or reproductive disorders. Among these health related culling reasons, “Hoof” (hoof diseases) is also important to note, accounting for 7.3%. 
However, a larger percentage of cows (4.1%) were removed from the herd due to “Uno” (unknown or unspecified) culling reasons. This may indicate missing data recording in cow files, particularly in some farms in China. There have been studies trying to ascertain why cows die on farm and from which diseases, but the information gathering is hindered by inaccurate and inconsistent data entry.
”Urg”(urgency)is also an important reason for culling. 4.1% of culled cows were sudden death or accidental injury, which exposed several problems in farm management.
Dairy cows, experiencing a disease or a reproductive disorder, are exposed to higher culling risks. This category of culls is usually designated as `involuntarily (or forced) culled cows', in contrast to all the other culls or sales, which are designated as `voluntarily (or selected) culled cows'. In Figure 4-22, only 8.83% were voluntarily culled cows and the highest voluntary or “selected” reason for culling is “MPro” (Low milk production) at 7.9%. That might show us farmers hardly cull their cows, unless the cows can’t bring benefits any more.
Possible reasons of fluctuation in culling rate may be the levels of milk production and milk and beef prices. Some farm managers suggest that these factors determine their culling decisions. So farmers may cull more cows in times of low milk production, low milk prices, and/or high beef prices. Some first results of our analysis show a negative relationship between milk price and culling rate.  As the milk price drops, the culling rate increases. It means that farm managers tend to remove more cows from the herd in times of low milk price, due to unprofitable production.

4. International differences in average productive life 

The great variation in Table 4-4 between all these countries in which Holstein-Friesian-type cows dominate the dairy cow population, suggest that farming systems play a role in determining longevity. Apparently dairy cows live longer in countries with grass-based farming systems (in New Zealand, United Kingdom and the Netherlands large part of the farms have grass based farming systems). One may add that the average production per cow per day is usually also lower on farms with grass based farming systems compared to cows in confinement systems. This could also lead to the assumption that these cows in grass based farming systems might be exposed to less metabolic stress resulting in a longer productive life. In USA, Canada and Israel the average production per cow per day is relatively high compared to the other countries in the table.


4.5.4 Sector approach to improve longevity in the Netherlands

As part of its Sustainable Dairy Chain Agenda the Dutch dairy sector has explored the possibilities to increase longevity by improving health and welfare of dairy cattle. A qualitative expert approach to appoint bottlenecks and solutions resulted in four key proposals to stimulate dairy farmers to increase in longevity at farm level:

1.      Create awareness about the added value of longer living cows by demonstrating results of farms that have increased longevity in the past and by using a tool that can forecast the financial results of adaptations in farming practices.

2.      Develop a Plan-Do-Check-Adjust (PDCA) approach and teach farmers how to work at farm level on their bottlenecks to increase animal health and welfare. The PDCA approach requires from farmers to appoint the performance indexes they want to improve and challenges them to define targets, actions and deadlines to achieve the desired higher level of animal health and welfare. Working this way is expected to increase longevity and the financial results of the farm.

3.      Create incentives to stimulate farmers to work on longevity. These incentives can comprise: workshops or trainings, bonus milk price or extra permits or licenses for farmers with higher average longevity level of the herd.

4.      Organize trainings about better labour organization to avoid that a high work load will result in suboptimal animal care.

Till so far the dairy sector has made a start with implementing proposals 2 and 3. The other proposals are not yet turned into actions. Proposal 2 has also led to the development of nine key themes to improve health and longevity: longevity, production, culling, transition management, udder health, fertility, claw health, rearing of young stock and use of antibiotics. For each of these themes experts have recommended performance indexes that can be combined to two one-page reports: one report for annual evaluation and another report for monthly monitoring and evaluation. The performance indexes for this monthly report are listed in Table 4-5.


This report is made to provide farm managers with a quantified insight into the status of their farm for these themes. It also offers benchmarking possibilities by comparing farm figures with average performance indexes of peer groups. And in the Netherlands farmers, veterinarians and other consultants are also stimulated to formulate their own targets for some key performance indexes. These indexes are also valuable in the process to of the PDCA approach mentioned before. Improving indexes might require the introduction or adjustment of certain standard operating procedures that can support the right actions needed to move in the desired direction. 

 

4.5.5 Recommendations to improve longevity in China

In China, there is almost no attention to cow longevity. Farmers and farm managers are prone to put all their reflection and energy on how to make profits from cows and how to reach milk production targets. So the first thing we may do is communicating farmers and farm managers the importance of increasing longevity of cows.

Surveys show that the major reasons for culling are reproduction failure, mastitis, and lameness. Our data also show the similar conclusion that reproduction disorders, udder-related disorders, digestive system disorders and hoof diseases are assured known causes of culling in China, accounting for 68% of all cullings. For most average herds these are the areas requiring attention to improve herd longevity.

Before, we have mentioned that milk production influences farm managers’ decisions. In fact, milk production is intimately connected to fertility and udder health. Hoof health and rumen health will also indirectly affect milk production. If a cow does not breed back and calve again, she will gradually (or suddenly) drop in production to levels beneath profitability. A mastitis cow produces less milk, if subclinical, or goes into the hospital group and incurs additional medical treatment and labor costs if clinical. Severe or chronic infections are costly.

If we want to increase cow longevity, we should improve the health and welfare of dairy cattle and minimize kinds of diseases of our cows.

The first step in improving longevity within a herd is to establish the current position by benchmarking key figures for the herd against group averages. Once a factor has been measured, it can be managed and priority areas can be identified for attention. Prepare a list of all culled cows in the last year. For each one identify the reason for leaving from the list. Then calculate some following indexes, such as:

1.         Culling rate

Take the total number of cullings over the 12-month period and divide by the rolling average herd size for the same period.

2.         The percentages leaving for each of the main culling reasons

Calculated by taking the totals for each reason divided by the total number of culls.

3.         Average lactation age (average parity)

Calculated using the latest set of records for the herd.

4.         Involuntary or forced culling rate

The total number of cullings for an involuntary reason divided by the rolling average herd size.

Using the calculated figures for the herd and comparing data with group averages, a farmer will find the  relative situation. If this relative position is suboptimal, then he  can select a herd strategy to achieve his optimal position (reduce overall culling rate or reduce the level of a specific reason). All the problems cannot be fixed at once. Draw up a priority action list and address the biggest problems first:

·           Identify the major reasons cows are getting culled and generate possible solutions. If all culling reasons are higher than expectation, start from focusing on one or two to determine causes and begin action plans to correct the problems. Further investigation is needed once a category has been selected to better understand reasons for culling and generate possible solutions

·           If the total involuntary culling rate is greater than average, or the involuntary cullings are over 60%[1] of all cullings or if the involuntary culling rate is higher than the farm target, there is opportunity to improve it. We can set an achievable guideline. However, the goal should be to minimize the involuntary cull rate.

·           Cows leaving the herd when less than 30 days in milk (DIM) usually are cows that have died or have serious metabolic or infectious disease problems at calving. It is important to distinguish between  cows that are culled and cows that die. Analyse the records to determine early lactation cullings and the broad categories causing cows to leave.The farmer should develop guidelines to support decisions about culling, especially for decisions in early stage of lactation (e.g less than  100 DIM)

·           Develop a farm specific action plan and set up a monitoring plan. Work with the appropriate team of advisors and employees to develop an action plan based on your on-farm investigations and also some key monitors to determine if your plan is working. Make modifications to the plan if it does not deliver the expected results.

 

4.5.6 Conclusions

1.      Longevity as indicator

In the Netherlands high longevity is considered as indicator for health and welfare of dairy cows. In China longevity is more connected to sufficient available young stock and milk price. In case of lack of young stock and high milk prices, longevity will increase. 

2.      Reasons for culling

The most important culling reasons for dairy cows in both countries are almost the same. Reproduction problems, udder problems and hoof problems are in the top 4 in both countries. The difference in top 4 reasons are: digestive problems on place 2 in China and other (clustered) health problems on place 4 in the Netherlands.

3.      Average productive life

Average productive life of dairy cows is 3.7 years in the Netherlands and first data of 19 Chinese dairy farms with an average herd size of 813 cows show an average productive life of 3.0 years. This productive life is exclusive the rearing period of about 2 years.

4.      Recommendations to improve longevity

In both countries we suggest to improve longevity by:

a.      Give the farmers clear insight into? their present longevity situation by benchmarking based on data about longevity, culling reasons and health problems.

b.      Make a priority list of targets on animal health and welfare that will support minimizing involuntary culling (action plan).

c.       Make a list of measures or best practices to adopt and apply them.

d.      Monitor results and modify the plan to make a better fit to the specific farm situation.

 

Acknowledgement

We thank  Erwin Koenen and René van der Linde of CRV for sharing data about culling reasons in the Netherlands and for their comments on draft versions of this paper. 


Notes:

1.CRV, 2015
2.Zijlstra et al., 2013 (data of Dutch farms during the period 2006 until 2012)
4.Analysis of longevity and reasons for culling high-yielding cows, Adam Oler et al., 2012
5.Reasons for culling in French Holstein cows, H. Seegers and F. Beaudeau, 1998
6.Preliminary results Ma Jiaying and Cao Zhijun, 2016
7.USDA. Dairy statistics[DB/OL]. 2013. Available at http://future.aae.wisc.edu. 
8.Source: CanWest DHI and Valacta
9.FAO, 2013. Available at http://faostat.fao.org/site/569/DesktopDefault.aspx?PageID=569#ancor 
10.Zijlstra et al., 2013
11.Uk M D C. Longevity - controlling culling to improve herd profitability.[J]. Publication - Milk Development Council, 2000.