The benefits of extra centimetres

Hi Ron, Very Informative article. Which is the best day for in ovo vaccination? People talk about in ovo nutrition? Can the extra length be improved through in ovo nutrition? Romila

Dear Mr. Ron, Good informative article. What are the factors responsible for maximum utilisation of yolk? What is the maximum percentage of utilisation of yolk during the incubation stage?

The best day of in-ovo injection actually depends on the development of the embryo. If the embryo is too small, you inject into the allantois, which means the vaccin is not effective. If the embryo is too big, you have a risk of injecting it in the breast, neck or head. That gives good vaccination, but of course bears a bigger risk for the embryo. As the temperature profile determines the speed of development, we can imagine that not all machines have the same optimum moment of vaccination. We know that for optimal results, some types of machines require a bit later injection than others, because their initial temperatures of the embryos are lower. But in general we are better off injecting too late than injecting too early, as the risk of injecting in the allantoic and then have birds that are not vaccinated at all is bigger than injecting to late and loose some chicks because of injecting them in the head or neck. In ovo nutrition is indeed a new development with a lot of opportunities. By injecting the eggs with nutrients, we can overcome a specific shortage that has developed during incubation, and in that way safe chicks that otherwise would not have the energy to hatch. Atthis moment I dont know if in ovo feeding can lead to more development. As the time from injecting to hatch is relatively short, we should not expect too much difference, but if we can compensate for a specific nutrient that is missing for development, we might see an effect.

The factor that seems to influence yolk utilization most is temperature. If the temperature is off, the development of the embryo is not optimal, and consequently the transition from yolk to embryo is not optimal, and more yolk is left over. The question about maximum utilization of the yolk is actually a question if the birds needs a minimum amount of yolk as residual yolk for the first days after hatch. I dont think we know that answer. A lot of people are of opinion that a bird needs a certain minimum amount, but the fact that all the chicks that die before 3-4 days of age in the field still contain residual yolk suggests in my opinion that there are not a lot of birds that die from lack of yolk. It seems to me that they die more often from not being able to take up the yolk, and not because there is not enough yolk left over for uptake. If that is the case, then in my opinion we better get maximum transfer of yolk into embryo during incubation, which means the less yolk is left over at hatch the better off we are.

This is a very beautiful article. It is full of intellectual material. However, the issue of in-ovo vaccination is a new innovation to me. I have never heard of it. It is not used in Africa. Anyway. If I know about the process, I may likely be the first to use it. My hatching factory will start operations in Nigeria, Moniya, Ibadan. We want people like Dr. Adejaro to be in contact with us. Dr. Adejaro is a member of this forum. He contributed with an article on this forum as well.

Bonjour. Je vous felicite pour votre travail et jespere avoir la chance de pratiquer cette methode. Bon courage.

Believe me this is a sincere and concerted effort made by a professional. The enlightenment made on the subject-matter are worthy of consideration for optimal diversion into hatchery performance for more quality chicks production. ...that an extra centimetre in development pays off. Now, if this assertion is anything to go by, then, the stakeholders (including the author) should go extra miles to research deeply into improving on the usage of in-ovo vaccines to address/correct the specific situation in the embryo such that would ensure better performance of the broiler chicks once- and- for- all. Thank you.

Surely in ovo vaccination is a recent technology of ealy chick embro vaccination, not yet practiced in Nigeria and many developing countries but frankly speaking it will soon become very relevant in the management of many post hatchery vaccination failures. A particular poultry disease of concern is Marek's that are vaccinated for at hatcheries, but to which embarassing outcomes of post hatchery vaccination is now a common features on the field. The pending challenge now is if an in ovo vaccination will confirm a solid immunity beyound 12 weeks of age? Can we be able to identify by empirical information post hatchery Marek's failure that can be traced to the hatchery as distinct from a direct field outbreak? If post hatchery immunity to Marek's fails at 12wks, is it possible to identify a best period to trigger an amnestic response to a hatchery vaccination with HVT vaccines? I have a 25-year cumulative data on post hatchery vaccination failures in Nigeria with very poor evidences of solid immunity. My study is still on going and I am interested in the role in ovo hatchery vaccination will play in solving this problem. I wish to draw attention of interested groups that may want to collaborate with me for this study to be free to contact me through Engormix.com. Thanks. Dr Stephen Adejoro

A very informative article which brings to light the importance of the processing of the hatching eggs from the time these are laid to the timing of setting. Additional research would be needed to find the correlation between the age of the eggs at the time of setting with the maturity of the embryo, hence the chick length and yolk free body mass, at the time of hatching.