According to minerals I think Vitamin E and Selenium

Multifactorial nature.

1. Genetics (modern dairy breeds have decreasing fertility)

2. Management (including oestrus detection, transition cow management, housing system, etc)

3. Nutrition (deficiencies and suboptimal levels, but also imbalance between main nutrients [carbohydrate, protein fat, minerals, vitamins])

4. Disorders (genital tract, generalised conditions, e.g. infectious, lameness, mastitis)

5. Level of production (inversely proportional relationship)

It is a common mistake to concentrate on only a single factor (like deficiency of microminerals) and not addressing the real situation. A holistic approach to the problem is required. Fertility is one of the production disorders. Therefore, the approach to a fertility problem should be addressed following the principles of herd health management.

Hope this helps.

High yielding dairy cows experience a more or less pronounced energy deficit in early lactation because feed intake is insufficient to provide enough energy for the rapidly increasing milk production. This negative energy balance negatively affects fertility and makes the cows more prone to various diseases, which are in fact most prevalent in early lactation. In this situation, cows are most sensible to insufficinet management practices. Or in other words: Feeding and management practices can in many cases not hold pace with the genetically determined high milk yield.

Another factor contributing to decreasing fertility seems to be the presence of dleterious alleles leading to early embryonic death in homozygotes. Some recent papers have focussed on these entities by analysing missing homozygosity.

So, in fact multifactorial.

I agree with the multifactorial approach but for strategically managing the herd the animal genetics cause our low fertility in Trinidad as well as poor quality forage and rations having insufficient quantities of the macro and micro nutrients essential for optimal fertility. So how do we counteract the low fertility?

Saying that rations having insufficient quantities of micro- and macronutrients implicates that you already know a part of the solution: optimize the feeding regime. Micronutrients can be supplemented. Other important factors like energy density, fibre and crude protein also need to meet the requirements of your herds. As I understand you, forage quality is aproblem in Trinidad. But: To manage high yielding cows there is no alternative to an optimized feeding regime. It would be interesting, though, which breeds are predominant in Trinidad as well as the level of milk production.

The breeds of dairy cattle are predominantly crosses of Holstein and Jersey breeds. Most farms no longer carry the big Holstein animals but a smaller version with the Jersey crosses. Milk production for the country I do not know exact figures.

True. Also bio availability of nutrients is important. Better the digestibility & absorption, better will be the overall health & performance

g.v.sudarshan

Would yeast culture increase fertility? I am hoping to increase milk production using it but I am not sure if it can have any impact on fertility.

Inbreeding depression may be caused fertility problem.

It may be affected by several factors viz. genetic, nutritional, health status, poor management, improper heat detection, failure of timed AI etc.

In a simple term better management in all aspect of animal keeping in mind the welfare and comfort of animals. Reproduction is luxury of any animal species. So if fertility is affected, it represents the animal is not in comfort due to any reasons and we have to correct the same to improve fertility. Now reproduction can be best managed by herd health approach as suggested by Mr. Kiro Petrovski.

Another thing to look at is the cattle in your operations in an "big picture" sense. How bad was the previous calving for that cow? Did she experience any problems such as retained placenta? Metritis? Milk Fever? "fresh-cow treatment" is the starting point for that cow for the next calving. That is the "starting line" so-to-speak. If she takes longer to get back to where a reproductively-sound cow needs to be, the producer will be fighting to get her bred back and is losing out on that money. This is the main thing I look at. As people have stated about, nutrition is a major point to look at also. Dry, lactating, fresh cow rations are allowing for a "happy" body. Being in that negative energy balance allows for problems to occur (such as breeding problems) to arise. Something has to give and one of the first things to go is reproduction.

When I breed cows, I like to choose the best bull for that cow (as best as I can do)

I frequently will use that particular bull twice. after that, I like to use a bull that has high conception rates. After 4 attempts, I either perform a reproductive soundness exam to see if myself or the cow is having an acute problem that is easily fixable or I cull her.

We use both AI and breeding bulls to increase conception.

remember reproduction is not a priority in the cow's energy partitioning therefore it on the lowest ebb of functional priority needs, so poor energy balance mainly affects it and above all human error or incompetence could also be considered as one major contributor to poor reproductive performance

Why AI and Breeding bull use for improving fertility? as suggested by Reishma Sankar. If you have the AI technology at a adequate level i. Quality frozen or liquid semen from elite or progeny tested bull; ii. efficient heat detection system; iii. efficient AI technician and very good reproduction management; I am sure that bull may be good for beef production system. However, where disease is a major concern for dairy breed AI is the best choice for keeping fertility at an optimum level.

Dear Reishma,

Apart from the aspects commented by the rest of colleagues, do not forget the followings:

- Negative Energy Balance: genetic improvement is leading to higher energy requirements that we are not able to cover and, as a consequence, fertility rates have been decreasing year by year (indrectly correlated to production level)

- Low level of inclusion of polyunsaturated fatty acids such as Omega 3 in many areas. These fatty acids have specific functions in the reproductive organs that favour reproductive performance.

Regards,

Alfredo.

Dear Reishma

In addition to the above, climate change such as heat and cold stress can also affect the fertility of dairy cattle.

Best Regards,

mohtashami

So many factors contribute to low fertility.  

bull, the method of insemination, the cow, the conditions of herd management and chance. Particular attention is paid to factors related to the conditions of herd management. These are the climate, the season, the size of the herd, the housing system, the choice of a bull, hygiene at the time of calving, the interval between parturition and the first insemination, detection of oestrus, the time of insemination during oestrus, nutrition, selection and the culling of cows.

Very interesting comments

Out-breeding or inbreeding? Which one is most important role for decreasing fertility?

Dear Reishma,

Low fertility has multiple reasons, and It is mistake to focus on only a single factor. but you should consider Nutrition, amount of production, health factors, management factors, heat detection, season, and genetic also.

Ready to describe more, if it is necessary.