1.3   INTERPRETING PROGESTERONE RESULTS

In addition to progesterone measurement, a clinical examination with vaginal cytology and vaginoscopy can further increase accuracy when determining the optimal breeding window. This corresponds to a gynecological examination of the female, where the appearance of the vaginal mucosa is assessed and a cytology sample is collected.

 

Because individual variation is significant, progesterone values should never be interpreted in isolation. Two females may show the same number on the same day of heat while being at very different biological stages. For this reason, serial testing is far more reliable than a single measurement. Observing the rise and speed of progesterone increase over time often provides more useful information than any single value on its own.

Many unsuccessful breedings are incorrectly attributed to the male or semen quality, when the underlying cause is simply that mating occurred before the eggs were mature or after the fertile window had passed. Understanding progesterone dynamics helps avoid these assumptions and allows breeding decisions to be based on biology rather than guesswork.

 

Progesterone testing does not remove all uncertainty, but when used correctly it significantly increases the likelihood of successful timing and provides a more realistic framework for evaluating breeding outcomes.

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​​​​2   MATING METHODS

Putting biology into practice​

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The choice of mating method should always be based on the female’s cycle, correct timing and the practical realities surrounding the breeding. No method can compensate for incorrect timing or disregard for the wellbeing of the dogs involved. Each method has its own strengths, limitations and requirements, which must be understood in order to make responsible breeding decisions.

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2.1   NATURAL MATING

Natural mating allows direct interaction between male and female and follows the dogs’ natural reproductive behaviour. When timing is correct and both dogs are comfortable, this method can be effective with minimal technical intervention. The natural lifespan of sperm within the female reproductive tract also provides some flexibility around the fertile window.

 

A key aspect of natural mating is the experience itself. Breeders should actively aim to make the situation as calm, safe and positive as possible for both dogs. This includes appropriate surroundings, sufficient time and avoiding pressure or haste. When handled responsibly, natural mating can be a positive experience that supports both physical and behavioural wellbeing.

 

From a practical perspective, natural mating is also the least costly option, as it does not involve semen handling, transport or veterinary procedures.

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2.1.1   WHEN NATURAL MATING IS NOT A GOOD OPTION

Behaviour plays a central role in natural mating. Females may clearly communicate refusal even when biologically fertile, and this communication must always be respected. The male’s safety must also be considered, as a stressed or defensive female can cause injury if the situation escalates.

 

In some situations, gentle physical support of the female may help her remain steady and calm during mating, but only when this can be done safely and without increasing stress. If the female clearly resists, or if the situation cannot be managed calmly and safely, forcing a natural mating is never acceptable. In such cases, artificial insemination is often a better and more responsible alternative than continuing with stressful or unsafe natural mating attempts.​​​​​

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2.2   ARTIFICIAL INSEMINATION

Artificial insemination with fresh semen is often chosen when natural mating is impractical or undesirable despite correct timing. It removes many behavioural and physical challenges while still using semen with a relatively long lifespan.

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Fresh semen can also be a suitable solution when logistics or previous unsuccessful natural matings make direct contact difficult, while still allowing insemination to be closely aligned with the female’s cycle. 

Although fresh semen offers some flexibility due to longer sperm survival, correct timing remains essential. Insemination should always be planned in relation to progesterone progression and egg maturation.

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Fresh semen insemination typically involves veterinary handling and therefore comes with some cost, unless the breeder has the experience and equipment to perform insemination themselves. While more expensive than natural mating, it is generally less costly than chilled or frozen semen solutions.

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2.3   CHILLED SEMEN

Chilled semen allows breeding across distance without transporting the dogs. However, semen quality begins to decline immediately after collection, making transport time, handling and storage conditions critical.

 

Compared to fresh semen, chilled semen has a shorter viable lifespan, which significantly narrows the margin for timing errors. For this reason, insemination with chilled semen is best carried out by, or in close cooperation with, an experienced reproductive veterinarian familiar with timing, handling and contingency planning.

 

2.3.1   TIMING, LOGISTICS AND RISKS FOR CHILLED SEMEN

Chilled semen is one of the most demanding breeding methods from a logistical perspective. Successful use requires that semen collection, veterinary availability, transport and insemination all align within a very narrow timeframe.​ 

Short notice changes, limited courier options and the inability to ship over weekends can quickly compromise success. Many veterinary clinics also have reduced or no availability during weekends, further increasing risk. Because chilled semen deteriorates continuously during transport, even relatively short delays can have a significant impact on outcome.

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It is also important to recognise that failures are not solely related to transport. Errors in coordination, timing, communication or handling at any stage of the process can be just as limiting as shipping delays and may directly affect the final outcome.

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Chilled semen is therefore both more complex and more costly than natural mating and fresh semen insemination, as it involves collection, packaging, shipping and coordinated veterinary procedures.

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2.4   FROZEN SEMEN

Frozen semen allows long term preservation of genetic material and offers significant planning advantages. Unlike chilled semen, frozen semen can be prepared, stored and delivered well in advance of the breeding.

 

This removes the need for last minute coordination of collection and transport and allows the breeder to focus timing efforts primarily on the female’s cycle. In complex breeding situations, this can make frozen semen a more predictable option than chilled semen.

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While frozen semen is more robust during transport than chilled semen and can tolerate longer shipping times, logistical delays can still disrupt planning and availability.

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2.4.1   TIMING AND PROFESSIONAL HANDLING OF FROZEN SEMEN

Once thawed, sperm survival is very short, often measured in hours rather than days. As a result, insemination with frozen semen requires extremely precise timing in relation to ovulation and egg maturation.

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For this reason, insemination with frozen semen is strongly recommended to be performed by an experienced reproductive veterinarian. Correct handling, thawing and placement are critical, and frozen semen should not be managed as a routine procedure.​ Also frozen semen should not be evaluated or compared directly to fresh or chilled semen, as expectations, handling and biological limitations differ fundamentally.

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Frozen semen is generally the most expensive breeding option. Costs are associated with collection, freezing, storage, transport and specialised veterinary procedures.​

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2.5   TRANSPORT RISKS

Logistics play an important role in both chilled and frozen semen breeding, but the level of risk differs between the two.

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Chilled semen is particularly vulnerable to transport delays, as semen quality declines continuously from the time of collection. The inability to ship over weekends and reduced veterinary availability during these periods significantly increase risk.

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Frozen semen is generally more tolerant of transport delays, but shipping still carries logistical risk. Periods of high parcel volume, particularly in December, should be avoided due to increased likelihood of delays or lost shipments. This also goes for chilled semen.

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2.6   CONCLUSION ON MATING METHODS

Natural mating, fresh semen, chilled semen and frozen semen each have a valid place in responsible breeding. The appropriate method should always be chosen based on the female’s cycle, correct timing, logistical realities and consideration for the wellbeing of both dogs.

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No method can compensate for incorrect timing, and no single approach fits all situations. Responsible breeding requires flexibility, biological understanding and a willingness to choose the solution that best supports both breeding goals and animal welfare.

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​​​​3   HERPES VACCINATION

Supporting neonatal protection​

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Vaccination against canine herpesvirus is worth considering, as the virus is widespread in the dog population and often carried without visible symptoms in adult dogs. In adult females, infection typically causes little to no clinical illness. The primary concern arises in relation to pregnancy and newborn puppies.

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Newborn puppies have an immature immune system and limited ability to regulate body temperature. If infected in the first weeks of life, canine herpesvirus can lead to severe illness or puppy loss. Because exposure to the virus is common, absence of symptoms in the female does not exclude risk to the litter.

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3.1   TIMING OF VACCINATION

Herpes vaccination is typically administered as part of standard breeding preparation. The purpose of the vaccine is to support the female’s antibody levels during pregnancy so protective antibodies can be passed to the puppies.

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The first vaccination is typically given at the start of the fertile window or seven to ten days after mating. The second vaccination is administered one to two weeks before whelping to ensure sufficient antibody transfer to the puppies.

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Correct timing is essential. The vaccine is designed to protect puppies during their most vulnerable phase and is not intended as a long term or annual vaccination outside of breeding context.

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3.2   PROTECTION AND LIMITATIONS

It is important to understand what the herpes vaccine does and does not do. The vaccine does not prevent the female from being exposed to or carrying the virus, and it does not eliminate the virus from the environment.

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Its function is to increase maternal antibody levels so puppies receive passive protection after birth. While vaccination can significantly reduce the risk of herpes related puppy loss, it cannot guarantee protection in all cases and should be viewed as a supportive measure rather than a safeguard.
 

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3.3   RESEARCH AND EVIDENCE
In the following link, you will find a veterinary Master’s thesis by Rikke Wendt Larsen from the University of Copenhagen, which shows that Canine Herpesvirus type 1 may play a significant role in neonatal puppy mortality and highlights the importance of prevention:

Canine herpesvirus-1 infection in neonatal dogs

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​​​​4   MYTHS ABOUT BREEDING

Separating assumptions from biology​

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Breeding is often surrounded by long-standing assumptions, traditions and simplified explanations that are passed on without being critically examined. Some of these beliefs may sound logical or be widely repeated, yet they do not accurately reflect reproductive biology or practical breeding experience.

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This section addresses common myths about breeding and places them in a biological and practical context. The aim is not to dismiss experience, but to separate assumptions from evidence and to encourage a more informed and realistic understanding of breeding outcomes.​

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“Dogs that cannot or will not mate are genetically incompatible”

One of the most persistent myths in breeding is the idea that if two dogs do not want to mate or cannot mate successfully, it must be because they are genetically incompatible or “not a good match”.

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There is no scientific basis for this assumption. Willingness or ability to mate is influenced by timing, behaviour, experience, stress, environment and physical factors, not by genetic compatibility. Dogs may refuse to mate even when biologically fertile, and successful reproduction can still occur using alternative methods when timing is correct.​

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“More matings automatically result in larger litters”

Another common misconception is that increasing the number of matings will automatically increase litter size. In reality, litter size is limited by the number of viable eggs available and their successful fertilisation and implantation.

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Repeated matings outside the fertile window do not improve outcomes and may instead increase stress for both dogs. Correct timing is far more important than frequency. When timing is wrong, additional matings do not compensate for the underlying biological mismatch.

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“The male determines litter size”

Small litters are often attributed to the male, but this view does not reflect reproductive biology. Litter size is primarily determined by the female through ovulation rate, egg quality, timing and uterine conditions.

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Even with excellent semen quality, a limited number of eggs will result in a smaller litter. While the male contributes to fertilisation, he does not control how many eggs are released or how many embryos implant successfully.

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“Litter size is consistent from cycle to cycle”

It is a myth that a female will produce similar litter sizes in every cycle. Ovulation rate can vary between cycles in the same female, even when health, age and management remain unchanged.

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Hormonal variation, subtle physiological differences and timing all influence outcomes. A smaller or larger litter in one cycle does not necessarily predict future results and should not be interpreted as a permanent change in fertility.

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​​​​5   NBT ON NBT

Myth or fact?

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Breeding natural bobtail to natural bobtail is often discussed with strong opinions, but the genetics behind the trait are well described. This section explains the inheritance mechanism of the T-gene mutation, what scientific studies show, and why breeding outcomes can vary in practice.

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5.1   BASIC GENETICS BEHIND NATURAL BOBTAIL

Natural bobtail (NBT) is caused by a genetic variation in the T-box transcription factor T gene, which affects tail development during embryogenesis. In breeds where NBT occurs naturally, the trait is inherited and can result in dogs being born with a naturally shortened or absent tail.

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The genetics behind NBT are often described in simplified terms, but in practice they involve specific inheritance patterns that influence both expression and reproductive outcomes. Dogs carrying a single copy of the mutation express a natural bobtail of varying length, while embryos inheriting two copies of the mutation do not develop normally.

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Expression of the trait can vary, ranging from very short tails to partial tails, and tail length alone does not provide information about the underlying genotype. Understanding that NBT is a genetic trait, not a cosmetic modification, is essential when discussing breeding decisions involving natural bobtails.

 

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5.2   INHERITANCE PATTERN OF THE T-GENE MUTATION

The following table summarises the currently understood inheritance pattern of the natural bobtail mutation and its biological consequences, based on published genetic studies:​​​​

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