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The fundamental steps towards reproductive efficiency

Marketing 16 March 2022 News

Effective reproductive management in dairy cattle means managing the entire dairy farm properly; its improvement should represent the ultimate goal of each dairy farmer. As a result of this improvement, milk production and costs will be optimized, there will be a reduction in days open for cows and in the conception age for heifers.

Many aspects have to be considered for the improvement of the reproductive performance in dairy cattle: thus, here is a brief discussion of the key steps.

Dairy breeding and genetics

Up to the beginning of the 2000s, the main goal for selection programmes traditionally used to be milk yield to the detriment of other significant traits, such as health and fertility. In the last 15 years, things have changed, and now these traits are considered in selection programmes. Successful achievements such as the increase in longevity and the reduction of calving intervals have been possible.

New tools and applications allowed to introduce improved phenotypes on dairy farms, thus helping farmers better exploit health and fertility traits.

Nutrition management makes the difference

There is a negative relationship between milk production and fertility, however this is not related to high milk yield. As a matter of fact, it is due to negative energy balance in early lactation. This means that the dry matter the cow consumes is not sufficient to meet the daily energy requirement. Milk production in the first period of lactation involves an intense energy consumption, but energy is necessary also for maintenance. In case of insufficient energy intake, the risk is to undergo ketosis, a metabolic disorder that may lead to a decrease in milk production and reproductive efficiency.

In transition cows, the main strategies aim at improving health by minimizing stress factors¹, supporting immune function and dry matter intake. Moreover, the administration of specifically designed diets is intended for the improvement of fertility by tackling mechanisms linked to negative energy balance or by supporting those pathways that are necessary for fertility.

Health management

The key action is controlling infectious diseases. Along with fertility management, veterinarians should regularly monitor the health status of animals to identify the presence of those pathogens known to compromise reproductive efficiency. Reduction in conception rates, fetal losses and abortions can be some of the consequences of specific uterine infections.

Heat and pregnancy detection, synchronization programs and artificial insemination

Oestrous detection represents one of the critical points. While visual heat detection requires a methodical and intensive approach, technology has allowed dairy farmers to rely on new practical tools (such as pedometers or activometers) or strategies (online hormone dosage – progesterone) for a more successful and precise detection.

In addition, oestrus synchronization programs can help ameliorate reproductive efficiency, but still rely on oestrus detection for the desired improvement in pregnancy rates.

One key element is dairy bull semen storage and application for artificial insemination (AI). During the production process, sperm undergoes a lot of stress, while the dilution allows to get several doses with fewer sperm count. For these reasons, it will be important to store semen properly on farms, and to handle it with care for a successful IA. This is particularly relevant for sexed semen, which undergoes a more intensive production process.

To detect pregnancy, direct or indirect methods can be applied. Direct methods include to determine pregnancy status include return to oestrus, rectal palpation of the reproductive tract and observation through ultrasound scanning. Indirect methods are based on qualitative or quantitative measurement of hormones or other compounds in maternal body fluids.

All these approaches are considered as part of precision livestock farming.

Improving reproductive efficiency by managing minor uterine issues

In the past weeks, we explored the valuable meaning of vaginal discharge in dairy cows². The ability to recognize what is behind vaginal discharge makes the dairy farmer intervene promptly and prudently in case of disease or physiological manifestations, such as those in late post-partum. Moreover, repeat breeder cows³ are an obstacle to reproductive efficiency.

In these cases, the dairy farmer can use OZOLEA no-withdrawal solution for intra-uterine use, OZOLEA-METR. In particular:

– in late postpartum, or about 30 days after delivery, when the uterine involution is complete, there are no clear symptoms of metritis but abnormal non-severe vaginal drains may be visible,

– 24 hours after insemination, when the embryo is forming in the tubes but before it descends towards the uterus for implantation.

References

¹ A comfortable pre-calving period for less stressed fresh cows.

https://www.ozolea.it/a-comfortable-pre-calving-period-for-less-stressed-fresh-cows/

² The meaning of vaginal discharge in dairy cows.

https://www.ozolea.it/the-meaning-of-vaginal-discharge-in-dairy-cows/

³ Acting on repeat breeder cows to increase herd productivity.

https://www.ozolea.it/acting-on-repeat-breeder-cows-to-increase-herd-productivity/

Crowe, M.A., Hostens, M. & Opsomer, G. Reproductive management in dairy cows – the future. Ir Vet J 71, 1 (2018). https://doi.org/10.1186/s13620-017-0112-y

Galli A., 2020. L’efficienza riproduttiva fra gestione e tecnologia.

https://informatorezootecnico.edagricole.it/bovini-da-latte/lefficienza-riproduttiva-fra-gestione-e-tecnologia/

Cover image: Ph. Megumi Nachev. Available here.

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What milking machine maintenance has to do with mastitis control

Marketing 28 July 2021 News

Milking machines have been designed to allow efficient milk harvesting and the maintenance of healthy teats. Since their function can lead to mechanical stress, regular checks and maintenance of the milking equipment are vital for milk production and cow health.

Along with the specific production system, several factors affect teat condition during and after milking. At machine level, major impacts will come from teat end vacuum, liner compression and the shape of the liner mouthpiece, especially when not properly selected and set.

In general, impacts caused by the milking machine on teats cannot be avoided, however they can be minimised.

First of all, the milking machine must be correctly set. Adequate setting aims at the achievement of a high milking performance, where a short machine-on time and the maximum milk harvest level are properly balanced. This has to consider also low impacts on teats.

Mechanical stress caused by the milking machine must be reduced and controlled. Efficient milking is strictly related to the regulation of machine settings, such as, but not only, vacuum and pulsation which have to be well balanced with physiological milk ejection. Moreover, as the interface between the mammary gland and the machine, the teat cup liner must fit the teat optimally.

Consequences on teat condition can be classified as short, medium and long-term effects. Changes occurring shortly and caused by circulatory impairment are: discolored teats, ringing, swelling, openness of the teat canal. These effects can be reversible. The observation of short-term effects¹ is strictly fundamental since this would help avoid long-term effects, such as hyperkeratosis.

Mechanical stress is one of the three main ways that make machine malfunction contribute to new mastitis infections. It would lead to teat and teat end damage, and also the reduction of the natural defense mechanisms of the teat canal.

Moreover, machines not functioning properly can behave as bacterial carriers and also facilitate the entrance of bacteria into the teat canal.

Milking machine problems find their reason in inadequate maintenance of mechanical components and elements that come into contact with teats. Checking them regularly should be the rule and part of a routine on dairy farms.

Training the staff to conduct these checks and including these activities as part of their responsilities become vital when more than one employee milk the cows. The aim is finding out any problem and alerting our technical service.

When should these checks be conducted? Every day, weekly and monthly.

Daily checks are extremely useful, since they will focus on air admission holes (they should not be blocked), vacuum gauge reading, pulsators (regular and intermittent sound), milk flow in receiving jar (it should be even), cows’ teat observation during and after milking.

Every week, we should check liner condition, filters and drain valves on pulsator airlines, regulators. If necessary, clean filters on the vacuum regulator. Moreover, we should check vacuum pump oil level

Checks conducted monthly aim at testing the effectiveness and regular functioning of the machine when it is running.

All these checks should take into account manufacturer’s indications.

As part of the routine, it will be good practice to record the outcome of each monthly check: although recording involves a little additional work, it allows a more rapid and easier intervention when changes are required. This is true not only for milking machine maintenance, but also for other dairy management activities.

What to do if we notice physical stress and signs of udder tissue disorders due to mechanical impacts? Supporting and protecting the tissue would be a helping hand to allow the cow to autonomously manage the tissue imbalance. OZOLEA-MAST can be your ally in this.

¹ What changes in milk tell us when we forestrip.

https://www.ozolea.it/what-changes-in-milk-tell-us-when-we-forestrip/

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The fate of antibiotic residues during and after cheese making

Marketing 23 June 2021 News

The EU regulatory framework for food safety sets out maximum residue limits (MRLs) in foods for drugs used in livestock¹. This criterion helps farmers provide safe foods on the basis of previous risk assessments conducted for veterinary medicinal products prior to their marketing authorization.

MRLs are defined with the aim of protecting consumer’s health. However, technological issues occurring due to drug residues may be an impediment to efficient dairy processing.

During cheesemaking, antibiotic residues follow distinct routes, migrating from milk to cheese or whey and decreasing during ripening. Also, we have already explored their effects on starter cultures⁶.

Interesting findings on the different routes for residues come from research exploring these issues (with residues compliant with EU MRLs) in Tronchón cheese, a traditional dairy product from Eastern Spain.

Depending on the physicochemical characteristics of the antibiotic, residues are transferred from milk to cheese to a higher or minor degree.

In a recent study², this aspect was assessed for the seven most widely used antibiotics (at MRLs) in dairy goats along with their effect on the cheese-making process and cheese characteristics during ripening. The resulting Tronchón cheese was assessed at 0, 30 and 60 days of ripening to determine pH, chemical composition, proteolytic and lipolytic activities, color and textural properties. A sensory evaluation of 60-day ripened cheeses was carried out.

Except for two different active substances, the cheese making process was not significantly affected by antibiotics. Variable concentrations of antibiotics (7.4-68%) were transferred from milk to cheese and, in general, residues tended to decrease during ripening, particularly at the beginning. Despite the decrease, relatively high amounts of enrofloxacin (148 ± 12 μg/kg) and ciprofloxacin (253 ± 24 μg/kg) residues were detected in cheese after 60 days of ripening.

The cheese-making process and the quality properties of the ripened Tronchón cheeses were only slightly affected by the presence of antibiotics in milk at an equivalent EU MRL concentration. By the way, these slight changes were not detected by the sensory panel.

In a different work³, the authors assessed the presence of oxytetracycline (at different concentration, lower and higher than legal MRLs) in goat milk and the effect on the volatile profile of ripened Tronchón cheese. Residues were largely transferred from milk to cheese, but significantly decreased during ripening (88.8 to 96.5%). The volatile profile of ripened cheeses was not affected by the presence of oxytetracycline in goat milk.

Another study⁵ indicates that, for most non-β-lactam drugs, there is a reduction (84–100%) in relative antimicrobial activity in whey, indicating that there is a higher susceptibility for retention in curd.

Moreover, Gamba et al. (2020)⁵confirmed previous findings about the effect of milk skimming on the reduction of residues: this process does not allow nor slightly allow the reduction of residue concentrations and a large amount of substances is transferred to the milk intended for further processing. In the same research, the authors determined the persistency in ripened soft cheese of one of the antibiotics investigated: after two weeks, the concentration dramatically decreased. Working with a different substance, the authors also noticed an inhibition of lactic acid bacteria that led to the ideal environment for microbial contaminant proliferation with alterations and defects of the cheese.

These findings give a broad perspective of the destiny of residues along the cheese making process. Working with undetectable concentrations seems to be technologically ideal. Now that we are facing an even harder challenge, that of AMR, alternative tools and best management practices become vital.

OZOLEA has designed and now is providing dairy farmers with innovative and sustainable tools for the reduction of antibiotics in dairy farming, allowing dairy processors to to obtain the best outcome from a residue-free milk.

¹ Reducing antibiotic usage can benefit dairy processing.

https://www.ozolea.it/reducing-antibiotic-usage-can-benefit-dairy-processing/

² P. Quintanilla, M. C. Beltrán, A. Molina, I. Escriche, and M. P. Molina, 2019. Characteristics of ripened Tronchón cheese from raw goat milk containing legally admissible amounts of antibiotics.

Dairy Sci. 102:2941–2953, © American Dairy Science Association®, 2019.

DOI: https://doi.org/10.3168/jds.2018-15532

³ P. Quintanilla, K.A. Hettinga, M.C. Beltrán, I. Escriche, M.P. Molina, 2020. Short communication: Volatile profile of matured Tronchón cheese affected by oxytetracycline in raw goat milk. VOLUME 103, ISSUE 7, P6015-6021, ^©2020 American Dairy Science Association®.

DOI: https://doi.org/10.3168/jds.2019-16510

⁴J. Giraldo, R. L. Althaus, M. C. Beltrán, M.P. Molina, 2017. Antimicrobial activity in cheese whey as an indicator of antibiotic drug transfer from goat milk. International Dairy Journal – Volume 69, June 2017, Pages 40-44

DOI: https://doi.org/10.1016/j.idairyj.2017.02.003

⁵ Gamba V., Bolzoni G., Monastero P., Losio M. N., Daminelli P., 2020. Residui di antibiotici sulle colture lattiche del siero innesto e nel formaggio. Grana Padano Insieme, Gennaio 2020, Consorzio Tutela Grana Padano.

https://www.granapadano.it/public/sfogliabili/grana-padano-insieme/gennaio-2020/#60

⁶Antimicrobial residues and lactic acid bacteria in cheese making.

https://www.ozolea.it/antimicrobial-residues-and-lactic-acid-bacteria-in-cheese-making/

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Reducing antibiotic usage can benefit dairy processing

Marketing 9 June 2021 News

From a food safety point of view, antibiotics (and, in general, antimicrobials) are chemical contaminants and, thus, pose risks.

In milk, the problem of residues is mainly related to the treatment of mastitis with antibiotics in lactation and at dry-off, but also to other diseases¹.

Being compliant with legal requirements for drug residues in milk is crucial to avoid public health issues – potential allergies in consumers, development of antibiotic resistant bacteria, negative impacts on intestinal flora.

Moreover, antibiotic residues pose technological issues due to their ability to partially or totally inhibit the growth and metabolism of starter and non-starter cultures used in dairy processing. All this can lead to substantial losses of dairy products.

Detecting the presence of antibiotic residues in milk at the processing plant gates is a routine procedure. This is aimed at excluding the non-compliant milk from processing.

According to the specific active substance, its residual concentration and the sensitivity of cultures used to process milk, different effects occur in dairy products. Thus, if in some cases there could be a slowing down of fermentation, in others the process could be even inhibited or blocked.

To give some examples, Lactococcus species are more sensitive to streptomycin and tetracycline, while they show a higher resistance to penicillin than S. thermophilus and thermophillic lactobacilli. L. delbrueckii subsp. lactis and L. helveticus showed to be less resistant to penicillin than most strains of L. casei and L. delbrueckii subsp. bulgaricus. Antibiotic residues may also influence the associative growth between two species, such as starter cultures selected for yoghurt production.

Negative impacts may occur both during and after processing, in particular at cheese ripening.

During processing, high concentrations of antibiotic residues can result in up to a full block of acidification after renneting, leading to high pH in cheese. Improper acidification also implies poor curd syneresis, soft coagulate particles and abundant whey and moisture content.

Other impacts can also be on texture (uneven), body (pasty) and flavours (yeasty, rancid or fermented). The reduction of flavours may be particularly intense in raw milk cheese, since residues will affect spontaneous flora in the milk.

Gamba et al. (Grana Padano Insieme, 2020)² collected interesting experimental data suggesting that certain current law limits in the EU for antibiotic residues still hinder some technological processes.

Being aware of these potential impacts of antibiotic residues during manufacturing, OZOLEA designed its leading product, OZOLEA-MAST, thinking of a beneficial effect also for dairy processors. OZOLEA-MAST does not contain active substances and does not leave residues in the milk.

The reduction of antibiotics along the dairy supply chain may lead to higher milk yields, less production losses, improved dairy product yields and a superior level of food safety.

1 Making money by saving milk

https://www.ozolea.it/making-money-by-saving-milk/

2 Gamba V., Bolzoni G., Monastero P., Losio M. N., Daminelli P., 2020. Residui di antibiotici sulle colture lattiche del siero innesto e nel formaggio. Grana Padano Insieme, Gennaio 2020, Consorzio Tutela Grana Padano.

https://www.granapadano.it/public/sfogliabili/grana-padano-insieme/gennaio-2020/#60

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Making money by saving milk

Marketing 5 March 2021 News

Sustainability is a tough word for many of us dairy farmers. Actually, we should think over how much it has to deal with the global management of our business. The better the dairy farm is managed, more the benefit.

It does not depend exclusively on how much we spend for green solutions.

Thus, let’s talk about economic and environmental sustainability in dairy farming without mentioning it throughout the post. What actually we want first is to be capable and brave managers on our farms, making the best out of our herd. And avoid milk discards.

Milk losses in dairy production stem from different critical factors.

Production diseases generate important economic losses. Among them, mastitis is recognized as the most impactful in terms of costs, followed by uterine issues, lameness and metabolic disorders. In these cases, losses are due to withdrawal periods for veterinary treatments.

Do the cows always really need to be treated? As already discussed, 85% of mastitis cases do not need the use of antibiotics since they are not severe – but from mild to moderate.

Thus, if milk cultures tell us we do not need antibiotics, we can decide for other revolutionary and innovative options. And, even before, a good approach to herd management should include preventive measures and a disease management plan.

How to dispose of the milk rejected from the tank due to withdrawal periods? Feeding calves with this milk is not a good option.

This milk can affect the microbiota in calves, with a negative impact on their health. And, as assessed by EFSA in 2015, it will lead to increased faecal shedding of antimicrobial-resistant bacteria by calves.

We will have an effect of this practice when we apply the slurry or manure to soil: the impact of antibiotic residues would be on microbiological and chemical balance of the soil, with negative consequences on soil life and methane emissions.

But this is a story to be told next time.

Bulk tank rejections by processor can also occur and it is usually due to antibiotic residue contamination detected at the plant gate. In this case, not compliant milk must be destroyed under veterinary supervision. Also, this often leads to penalties for dairy farmers.

Thus, use antibiotics when really necessary and ideally test the milk after the withdrawal period to be sure it is compliant to law.

Infrastructure issues, such as from the filter, buffer tank and washing through the pipes after milking, can lead to milk loss. From spills, accidents caused by lapses in management, when transferring milk to the tanker, or during power cuts, as well. Implementing strict management routines along with the aid of alarms and modern filters in the parlor system can help us reduce these losses.

And what about GHG emissions? A study conducted on Scottish dairy farms¹ showed a decrease by 0.6 and 3.1%, respectively, when milk losses from rejected milk and from farm infrastructure were reduced through improved management procedure and help from technology.

We implied “sustainability” throughout the post. Being a good manager on our dairy farms can really lead our business to be more sustainable for our animals, our profit, the environment, for the society.

Does it sound good?

¹March MD, Toma L, Thompson B and Haskell MJ (2019) Food Waste in Primary Production: Milk Loss With Mitigation Potentials. Front. Nutr. 6:173. doi: 10.3389/fnut.2019.00173