dairy cows | OZOLEA

Preventing and/or controlling subclinical mastitis is good for everyone, including the atmosphere

Marketing 26 March 2021 News

In some of the articles published recently in OZOLEA’s website, we discussed the importance of controlling mastitis aiming at improving animal health, dairy production and, therefore, profit. In other words, we should focus on efficiency, which means an optimized use of inputs per specific quantity of output – milk.

Here the articles OZOLEA published: “What changes in milk tell us when we forestrip” and “Making money by saving milk”.

Striving to achieve all these goals also have positive and beneficial effects on the environment.

Thus, let’s discuss again about sustainability without mentioning this word throughout the post. We will make a simple overview of a scientific study¹ conducted in Norway (Özkan Gülzari et al., 2018).

Poor animal health and welfare conditions leading to clinical and subclinical mastitis may compromise production efficiency. This occurs as the result of increased mortality, reduced milk yield, reduced reproductive performance, and increased animal replacement rates.

Being mastitis one of the hardest issues to treat in dairy cows, it has been recognized as an impediment to perform an efficient and feasible livestock production.

Mastitis means milk losses due to reduction in milk yield, discharge of milk due to withdrawal periods and more dairy cows lost and replaced. Moreover, if the disease is in the form of subclinical mastitis it is hard to detect visually at udder and milk level.

The researchers focused on subclinical mastitis in Norwegian dairy farms. It is more difficult to detect visually subclinical mastitis than clinical mastitis. Therefore, there is more room for prevention and control of clinical cases with respect to subclinical cases.

Subclinical cases can be detected by checking the SCC (> 200,000 cells/mL) and deciding for milk culturing.

The results reported by Özkan Gülzari et al. (2018) were in terms of impacts of five different SCC levels on milk yield, feed intake, culling rate and net margin (expected net present value ENPV) and emission intensity.

Milk yield decreased as the level of SCC increased in all the scenarios, reflecting the impact of disease on production, as reported in table on the left.

Reduction in total feed intake occurred as SCC increased. It resulted lower in primiparous cows (1.4-2.8%) than in multiparous cows (3.3.-6.6%).

For culling rates, in the range from 400.000 to 800.000 cells/ml, there was an increase as the SCC augmented (30.9-43.7%), with an impact on average longevity of the herd.

The highest net margin (ENPV) was observed at 200,000 cells/ml. This parameter was mainly driven by milk yield and milk and feed market prices.

Impaired animal health also means increase in greenhouse gas (GHG) emissions produced per unit of milk. The findings for emission intensities were 1.01 kg and 0.95 kg CO2/kg for fat and protein corrected milk in primiparous and multiparous cows with the lowest SCC (50,000 cells/ml), respectively.

Keeping subclinical mastitis at bay, as it can be for other diseases, can be perceived as a strategy useful both to improved inputs exploitation and a strategy to reduce the GHG emissions intensity from dairy farming.

This was the perspective from Norwegian dairy farms. Performances for any parameter here described would probably give different values depending on the European area assessed.

However, these findings can give use a brighter idea about udder issues: doing our best in preventing and controlling diseases at dairy farm level will pay off.

And this is completely sustainable.

¹Şeyda Özkan Gülzari, Bouda Vosough Ahmadi, Alistair W. Stott. Impact of subclinical mastitis on greenhouse gas emissions intensity and profitability of dairy cows in Norway. Preventive Veterinary Medicine 150 (2018) doi:https://doi.org/10.1016/j.prevetmed.2017.11.021

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A comfortable pre-calving period for less stressed fresh cows

Marketing 24 March 2021 News

The highest risk period for infections related to mastitis is that occurring around calving and the reason why is quite clear: during this period, the cow faces several physiological and metabolic changes, while her natural defensive mechanism is lower. This means a higher susceptibility to infections and udder issues, and much more.

The incidence of mastitis in the first month after calving is high: special management during the period around calving will help us keep cows healthy and make milk production profitable. Any issue occurring from three weeks before to three weeks after calving can negatively affect the rest of the lactation, both at cow and herd level.

Physiological, metabolic and endocrine activities during the periparturient period are quite challenging for the dairy cow: rapid differentiation of secretory parenchyma, exceptional mammary growth, abundant synthesis and secretion, and intense accumulation of colostrum and milk occur.

Particularly before calving, the cow’s mammary gland are noticeably vulnerable to infections. Thus, the effectiveness of a good dry cow treatment is essential, but not the only strategy that needs to be implemented. Management becomes of paramount importance and many are the critical points that deserves the highest attention of dairy farmers.

Environmental bacteria remain a hard challenge during this period and we have to rely on methods of controlling mastitis. Thus, we will strive to make the housing environment a better place for the cow.

In addition to the lower defense mechanism and the threat of environmental pathogens, we have to consider stress stemming from different situations that the cows go through. Cows generally respond to stress in terms of behavioral, immunological, neuroendocrine, and autonomic responses.

Great importance is given to the specifically designed ration to meet the cow’s nutritional needs during pre-calving but this is not the only determining factor for her performance and health during the imminent lactation.

Other aspects impacting the cow around calving are related to stress affecting the animal, such as overcrowding, moving cattle between groups and animal management. In addition, a well-designed stall, trained personnel (untrained workers are a real risk for any cows on the farm) and space management are essential.

Moving cattle between specific groups is of great significance, in particular for primiparous cows. Depending on the natural existing hierarchy among cows of different ages, primiparous cows will be subordinate by the multiparous cows and the agonistic effect is amplified any time overcrowding happens. The consequent risk of moving cattle and hierarchy is to have a reduced intake of ration in addition to stress. As preventive measures, we must therefore limit the number of moves around calving and keep overcrowding at bay in the dry cow, close-up/calving and post-calving areas.

Being aware of the hierarchy established by multiparous cows, we must consider creating more homogeneous groups on the basis of age to reduce the effects of competition.

How many groups should we evaluate before calving? First of all, a dry period group (average period of 60 days), which should be located adjacent to the close-up/calving group (here is where we will move cows 14-21 days before the estimated calving date, never less then 10 days before). Then, we have to consider post-calving group of fresh cows that must be monitored for a few days.

These ideal groups must take into account, in a real dairy farm, the available space, the presence of trained personnel able to carry out both the group moves and the progress within the group and the feasibility in terms of management. Thus, there will be farms where, immediately after calving, the cows will be transferred in the lactating group. However, it is good to keep in mind that every management choice made has effects on the cows’ welfare and therefore on performance.

To reduce stress due to the re-established hierarchy in each group, in particular to avoid effects due to retarded move in the close-up/calving group, we should consider the general rule of moving animals in groups weekly and not daily.

Crowding density represents a critical point: we should be able to adequately estimate the proportion of the lactating herd that will be in a certain period of the lactation as to evaluate with a discrete accuracy the space needed for cows in any group. Managing the number of animals in the various groups is not such a simple and mathematical thing because, due to the seasonal influence on fertility, the number of calving events will rarely be constant throughout the year.

The areas intended for close-up/calving groups should ensure comfort, hygiene, safety and space for the cows, but also make things easier for the worker. They can be individual or collective boxes, but in both cases the best option is deep litter housing compared to cubicles, although these guarantee sufficient comfort. If you plan to prepare an area that will house the close-up/calving group, then a collective box, you will first need an area that is oversized in relation to the number of cows. While moving cattle, we must avoid moving the cows in the group too close to the date of calving, as indicated above. The goal is to give the cow the necessary time to get used to the new environment and avoid stress.

Having enough space to separate fresh cows in the post-calving group for about ten days (maximum 14 days) is certainly very useful, especially for the observation of primiparous cows. Fresh cows can thus be monitored to check their nutrition, rumination and health status. If the cow needs treatment, it will be moved to the nursery pen, if on the other hand she is in good health conditions she can be transferred among the lactating cows.

The ability to manage transition cows according to these principles will not only give them a more comfortable environment, but will also reduce the occurrence of problems related to calving: this reminds us how training is vital for the entire life of our dairy farms. .

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What changes in milk tell us when we forestrip

Marketing 17 March 2021 News

When our milking system is not automatic, early detection of signs of mastitis strongly depends on the ability of the milker to recognize any specific signal at cow, udder and milk level.

This is something we should deeply focus on since it would allow us to intervene promptly with the right tools. Depending also on other factors, inefficient identification of these signs would potentially lead to clinical cases.

We are all aware of the importance of good management and prevention, and early detecting mastitis is clearly included in the effective preventive strategies to set up on dairy farms.

In this article, we will focus on signs shown by the cow at milk level, in particular how milkers can recognize them and what these signs tell them.

Alterations in milk reflect the unbalance condition of the intra-mammary tissue. The different forms of mastitis show specific signs at all observable levels – cow, udder, milk.

We will not see visible changes in milk but an increase in its somatic cell count (SCC) for subclinical cases. When dealing with chronic mastitis, milk shows mild changes (e.g., wateriness). At the very early stage of mild cases, we find a few flakes or clots, while in clinical cases clots are clearly observable. When clinical mastitis gets acute the milk is abnormal, both in colour and in clots and/or blood. Finally, in case of severe clinical cases the milk may initially look normal, while the cow is sick, but soon it becomes abnormal (wateriness, blood stained).

Foremilk stripping is a key step for a good milking routine. It allows the milker to get a faster milking through the natural release of oxytocin, to avoid initial overmilking and to early detect signs of mastitis, from mild to severe.

All the efforts put to detect these signs at foremilk stripping are worth it, even when we deal with large herds. We will have less somatic cells in the tank and reduce the risk of chronic infections, along with the proper intervention.

Let’s stress it out again: the opportunity to get the problem solved lies in the ability of the milker to early recognize these signals and read them correctly.

When the milker finds a few small flecks in the first three squirts of milk from a quarter, technical advice would suggest to leave it untreated and check the quarter at the next milking. If the condition worsens, think over milk culturing to look for pathogens and verify the individual cow SCC history.

This will help to confirm whether an antibiotic treatment is needed or not. As we already discussed, 85% of mastitis cases is from mild to moderate and milk cultures suggest the cow does not need antibiotic treatment. The cow will have two options: autonomously recover or worsen. Actually, OZOLEA can provide you with the third option – OZOLEA-MAST.

A compromised intra-mammary tissue is more sensitive to a potential bacterial attack: protecting it will allow the milker to help the tissue to autonomously regenerate and exert its function.

An overview of the worst-case scenario may be helpful to understand the importance of paying more attention at foremilk stripping and protecting the intra-mammary tissue (before the situation gets worse than a tissue unbalance).

When it occurs, mammary tissue damage reduces the quantity and activity of epithelial cells, consequently contributing to a decrease in milk production. The scientific literature shows that this damage can be induced by either apoptosis or necrosis, two death mechanisms characterized by specific morphological, biochemical, and molecular variations in dying cells.

During an intra-mammary infection, bacteria and the compounds they release can cause the tissue damage. Later, the massive immune reaction can further contribute to epithelial tissue damage. Some bacteria will be able to destroy cell membranes, reducing drastically the functionality of the milk producing tissue; others will be able to colonize and multiply inside the bovine mammary cells before killing them.

The massive migration of somatic cells triggered by the immune response is towards the mammary gland, where a breakdown of the blood-milk barrier is caused, further contributing to the tissue damage. The immune response by polymorphonuclear neutrophils involves the release of reactive oxygen intermediates and proteolytic enzymes.

Alterations in milk reflect the degree of physical damage to the udder tissue. Since the blood-milk barrier is damaged in clinical and subclinical mastitis, junctions between mammary epithelial cells weaken. Thus, blood and extracellular fluid components will easily escape into the lumen of the alveolus. Consequently, these components mix with milk and lead to an increase in pH, influencing the chemical stability of milk.

We also know that in case of infections we have an increase in somatic cells in milk, thus this is a key measurement for understanding the udder health status. But it is worth noting that increased SCC can also be related to non-microbial issues that affect the udder tissue as a result of changes in environmental conditions, nutritional disorders, stressful conditions, microtraumas, etc.

In conclusion, being able to identify and distinguish the cow’s udder status will help us in understanding the situation, assessing the possible action to take and promptly intervene with the proper solution.

Foremilk stripping is another simple, easy to implement and affordable solution for all dairy farmers. Another gun to arm ourselves with for the reduction of antibiotics and against milk loss.

In some dairy farms, the owner is directly involved in the milking process. In others, dairy farmers rely on milkers, who will have therefore a high responsibility in observing the foremilk at stripping.

As employers, dairy farmers should make the working environment as comfortable as possible, focusing on proper training sessions with employees to make them aware of the importance of a good observation of milk at forestripping.

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A more valuable manure for better crop productivity

Marketing 12 March 2021 News

This brief post is meant to be the second one of a discussion series about sustainability without mentioning this word. Our main goal is to be highly efficient and good managers on our dairy farms, before making major investments.

Last time, we had a story to tell about good manure quality. We saw how feeding calves with milk rejected from the tank due to withdrawal periods is not a good option both for calves’ health and chemical and microbiological characteristics of soils when spreading.

What about crop productivity? A proper waste management and a good quality manure can help us give the right boost to our crops.

As dairy farmers, we rely on homegrown crop production. This is a great opportunity to dispose of the waste produced by our dairy cows using it as a fertilizer to meet nutritional demand of crops. Also, it is a good opportunity for the economic optimization of our own entire dairy system.

A recent meta-analysis¹ assessed more than fifty scientific studies to compare the use of dairy manure with synthetic fertilizer.

This meta-analysis showed that, when applied at rates providing equivalent levels of plant-available nitrogen content, the effects of dairy manure on crop production, quality, and digestibility were positively equal to those achieved with synthetic fertilizer.

In particular, manure application increased soil organic matter, with a suggested overall positive impact on long term-fertility. The meta-analysis reported a high variability across the studies for soil nitrate leaching and nitrous emissions, concluding that no clear trends were evident.

An increase in soil phosphorous with a potential threat to water quality may be a risk related to dairy manure application.

The good thing is that, if applied with care to limit above impacts, dairy manure is a suitable fertilizer. It is worth noting that these impacts can vary with site-specific factors (climate, soil type, and application procedures).

Now, let’s go back to the antibiotic issue. A proper management of antibiotics in dairy cows is important for our crops, as well. Dairy manure can introduce chemicals (antibiotics) and pathogens (yes, including resistant strains from calves). How do antibiotics impact the soil, in short?

Depending on a number of different factors (physical and chemical properties of the substance, climatic factors, characteristics of the soil) persistence of antibiotic residues in the soil is determined mainly by sorption to organic particles and degradation/transformation.

The effects on soil microorganisms are the change in their enzyme activity and ability to metabolize different carbon sources and an alteration of the microbial biomass and heterogeneity of microbial communities.

Soil biodiversity plays an important role in ecological processes, and this is true especially for microorganisms, most importantly for their positive role in the maintenance of soil and water quality.

Thus, we owe our crops and our fields a good waste management and rational antibiotic use – it is beneficial for us first! Now, let’s go over good manure spreading:

never forget about local and national relevant rules on manure application to soil;
know the nature and characteristic of the soil – it helps avoid water pollution;
be sure to maintain non-spread zone near vulnerable areas – water sources, settlements, etc.;
highly fertile soils do not need high quantity of fertilizer;
consider proper weather and soil conditions for the application;
pay attention to timing and level of application on heavy or impermeable soils, areas subject to flooding and sloped grounds.

¹ Peter L. O’Brien and Jerry L. Hatfield. Dairy Manure and Synthetic Fertilizer: A Meta-Analysis of Crop Production and Environmental Quality. Agrosyst. Geosci. Environ. 2:190027 (2019) doi: 10.2134/age2019.04.0027

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Blanket dry cow therapy, ban on prophylaxis from January 2022. Any alternative? Selective treatment

Marketing 11 March 2021 News

One week ago, we introduced the new VMP Regulation. Among the key measures, it will reinforce the EU’s strategy against antimicrobial resistance (AMR) by introducing a ban on the preventive use of antibiotics in groups of animals (prophylaxis) and other restrictions on irrational and unnecessary use of antibiotics. They will be used only by way of exception.

When thinking of prophylactic treatments in dairy cows, the one immediately coming to mind is blanket dry cow therapy (BDCT).

When it was first introduced more than seventy years ago, it was a revolutionary approach since it made possible for dairy farmers to deal with major udder issues as a treatment for intra-mammary infections, at the end of lactation and as a preventive measure for potential new infections at dry-off, which is one of the most delicate moment in a cow’s life.

Things have changed, and, with the help of veterinarians and technicians, dairy farmers have been playing their part in prevention better and better, year after year. Thus, while in the past blanket therapy was well justified by several reasons, now for many dairy farmers it is no more necessary.

On the contrary, it could be really detrimental, and the risk is substantially linked to AMR.

A not brand-new approach but the future: selective dry cow therapy

Despite these considerations, for all the EU dairy farmers BDCT, as a prophylactic treatment, will be banned from 28 January 2022. Time is running out, and in this pretty short period of time the ideal transition would be towards the application of selective dry cow therapy (SDCT) for all the dairy farms.

SDCT allows the dairy farmer to identify and individually treat cows or quarters likely to be infected at dry-off. Recently, scientific research has been able to verify whether SDCT could be successful in protecting udder health and to describe its effect on antimicrobial use and economics.

Actually, some dairy herds are not yet ready for SDCT.

What conditions should a dairy farmer consider for the introduction of a SDCT program in their dairy herd? Let’s make an overview.

Herd eligibility: what parameters?

SDCT can be really effective in those dairy herds with a good history of milk quality and dairy herd health. Despite its potential, SDCT involves some risks, thus we must ponder some aspects to have a successful SDCT program.

Specific questions should be made and, if the answer to all of them is yes, the herd is eligible for DCST.

Are somatic cell counts (SCC) and mastitis issues under control? At least, the followings have to occur:

bulk tank SCC constantly below the reference value of 200,000 cell/ml in the current lactation;
contagious mastitis pathogens (Staphylococcus aureus and Streptococcus agalactiae) under control;
no infections (including subclinical issues) at the time of drying-off;
no clinical mastitis events during current lactation.

We also have to think over the conditions of the environment where cows live. Are facilities for dry cows good and proper management practices in place? We will need:

excellent hygiene measures at dry-off and in calving facilities;
cleanliness maintained in housing;
the right space (1 cubicle) per each dry cow;
regular checks for any sign of mastitis.

To approach the correct SDCT program for any dairy herd, consulting veterinarians and attending training courses will be essential for the proper implementation of the therapy.

Once we have set up the SDCT program, methodically monitoring the work in progress is essential!

When the questions lead to “no”: how to prepare

When the dairy herd is not yet ready for a selective dry cow treatment, the farmer should rethink the principles on which the prevention of new infections is based. Here some basic indications:

careful hygiene management in lactation, dry period and calving facilities;
proper use of teat sealants when drying-off;
adequate management and attention in the specific diet variations during the cow’s transition period;
improvement of management and recording skills.

Remember, knowing the lactation history for each cow, for any related aspect (intra-mammary infections, treatments, SCC, etc.) is one of tool for a good SDCT program. Let’s start working on it consistently!

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Clean cows make clean milk: tips and tricks

Marketing 10 March 2021 News

Last Monday we had the opportunity to attend the webinar presented by Jim Davenport, New York dairy producer and National Mastitis Council member, and hosted by the US leading dairy magazine, Hoard’s Dairyman.

Jim Davenport shared the tools used in his dairy farm, Tollgate farm, to ensure only the highest quality milk goes into the tank. Tollgate is one of the 10 family dairy farms that produce the milk for Hudson Valley Fresh Dairy, a local reality that provides dairy products (milk, cream, yoghurt) to consumers with a particular attention to freshness and quality.

Hudson Valley Fresh also sells dairy products in New York city.

Jim is a fourth-generation dairy farmer. He got a degree in engineering at the University of Connecticut and worked as DHI supervisor for some years before getting back to dairy farming, where his heart has always been.

The attention to detail allowed the family farm to be awarded with platinum milk quality awards from the National Mastitis Council. The only dairy farmer in the nation ever to do so, as you can read here.

Let’s have a look at basic information about the Tollgate farm, located in Ancramdale since 1993. There are 64 milking cows in Tollgate. The herd consists of 70 purebred Holsteins, with a few Ayrshires descendant from Jim’s grandfather’s herd started in the 1930s.

The family manages 140 acres and began shipping milk to Agri-Mark cooperative in 1986. The family puts a lot of effort in maximizing forage in cattle ration (<70% homegrown forage diet). Their milk has an interesting average somatic cell count (SCC) – 33,683 cell/ml from 2020 Agri-Mark Cooperative Data.

What to do to make the cows produce clean milk? Here the points to ponder:

the cow’s environment must be a challenge free zone;
the dairy farmers should know each cow’s udder health;
the cow’s teat is the most important milk contact surface on the farm;
teat-dipping plays a strategic role in hygiene.

At Tollgate farm, the family pays great attention to the cleanliness of the stall. Here is where the cows generally spend much time, thus it should always be a clean, dry environment – a tough enemy for bacteria.

In Davenport’s dairy farm, scrubbing away the dirt, investing a lot in fresh sawdust bedding and carrying out good stall maintenance are key actions to make the environment hostile to microorganisms. It is worth noting that here the cows find every morning, after they get back from the exercise, fresh and dry sawdust and a clean place.

Outside Tollgate, when Jim was a DHI supervisor he had the opportunity to check over 70 herds, and two of these were large dairy farms (3000 dairy cows) with really low SCC.

What did these large farms have in common? Attention to cleanliness, carried out daily with stall maintenance every day, keeping a constant eye on udder hygiene.

The most important milk contact cow surface on the farm is the cow’s teat. At Tollgate, udder is always pretty clean: this is due to their attention to udder hygiene before and after milking.

Udder health is worth attention. Properly conducting the California Mastitis Test (CMT) would help identify major udder problems with good accuracy at quarter level. At Tollgate, CMT is used to screen all the fresh cows before they enter the tank. It takes time to get acquainted with the CMT, it is a matter of practice and experience.

When the cow does not show a good result at CMT, milk is cultured. 65% of cultures tests negative: the cow being healthy and with robust immunity will help, also in case of treatments when necessary.

The thing Jim wants to know about each cow is the individual SCC: this value influences the bulk tank SCC and it is an important indicator of the cow’s udder health status.

At Tollgate, there are no major issues with pathogens: E. coli and Klebsiella are extremely rare, while they had some gram-negative bacteria and no occurring environmental microorganisms.

Things to do before and after milking are also important to produce clean milk. The first step at Tollgate farm, before forestripping, is checking each cow’s udder. The point is to detect moisture and dirt by grabbing the teat and observing it, and eventually removing undesired dirt.

Then they proceed with the milking routine: they forestrip, then pre-dip with a non-return dipper. After waiting for around 60 seconds, they dry the teat with a paper towel and then attach the cluster with minimal or no air intake: the machine must be positioned properly for even milkout. Finally, they remove the cluster when the vacuum has been completely released and post-dip.

A proper dipping is critical since it helps the dairy farmer to wash away and kill any potential bacteria. The goal at Tollgate is to attach the cluster to perfectly clean teats.

Washing routine involves any tool used to check the cows (CMT paddle) and the dipper. Left-over dip is thrown away, while the fresh product is at good storage conditions.

Jim gave us a good idea of the importance of cow teat as a milk contact surface.

Imagine you are a microorganism, attached to the teat and you are hungry, thirsty and in dry and hostile environment. Then comes the teat dipper that washes you down to the floor, while the iodine oxidizes your cell wall until you blow up.

Being in “bacteria’s shoes” in this case would not be a good sensation: thus, on our dairy farms we must do anything in our power to make bacteria uncomfortable.

“It is not rocket science, but you have to care”, Jim would say. Even more than this if we run an organic dairy farm.