Breeder management: Do not forget the males

Breeder management: Do not forget the males

Trace minerals play an important role in broiler breeder nutrition. These essential nutrients improve breeder performance, embryo development and chick health. Their effect on males and overall flock performance is often underestimated. Therefore, more attention should be given to trace mineral nutrition and male management.

By Wiebe van der Sluis, 
Rooster 45, the Netherlands

More than 130 broiler breeder specialists attended the broiler breeder seminar organised by Zinpro in Madrid, Spain earlier this year. In his openings remarks, Max Winders, vice president of sales – International, Zinpro Corporation, told attendees that everyone is aware of the importance of broiler breeder management, however most of the time only the breeding companies organise gatherings on this subject. “We felt the need to shed some light on issues that are frequently paid little attention to,” said Winders.

The international programme included four speakers with diverse backgrounds covering subjects ranging from breeder fertility, hatchability and welfare, to early embryo nutrition, as well as feeding and management recommendations to optimise broiler breeder performance.

The first speaker was Dr Jeanna Wilson, Professor at the University of Georgia, USA. She reinforced to attendees that there is much talk about female breeder management but little for males, however everybody knows that roosters play an equal important role in producing broiler chicks.

Rooster management requires more attention, Wilson said. Roosters must stay fit and interested in hens and be able to complete matings. Therefore, males should be discouraged from depositing breast meat by restricting feed and providing a special diet. Even then, fertility may drop. One of the main causes for such a drop in fertility can be found in aging and the natural relationship between bird behaviour and physiology. Aging roosters may become less interested and not able to complete matings, while older hens physiologically need to be mated more often in order to sustain the same level of fertility.

Encourage mating behaviour
To get good fertility in broiler breeders, males should have excellent testicular growth. Its development should be maintained by consistent daily restricted feeding after getting to the hen house. If the roosters lose weight, fleshing or general condition, the testes will regress in size and accelerate the natural decline. This regression will be accompanied by lower testosterone levels, semen production, as well as decreased mating behaviour.

Mating behaviour has to be encouraged without taking all energy from the bird. Body weight and fleshing has to be maintained, while preventing excessive breast fleshing. As the flock ages, the number of roosters should be increased and spike the aging flock with young, mature roosters. The best time to spike, according to Dr Wilson, is when the flock is 40-45 weeks of age by adding 100-200 males. Meanwhile, obvious culls and large non-productive males should be removed. Removing ‘pretty boys’, the large well-feathered males ruling the feeder and interrupting productive mating activity, also increases fertility. The spike males must be 25-28 weeks old and should weigh 20-25% more than the average body weight of the hen flock.

In addition to this advice, Dr Wilson also listed a number of practical facts that should not be ignored by broiler breeder managers. These include: nest selection, nesting behaviour, feeding practice and providing water and feed to males at the floor (not at the slats), frequent egg collection, storing and cooling hatching eggs, and removing cracked and dirty eggs.

Feeding minerals to embryo’s
Most broiler breeder managers know a lot about broiler breeder nutrition but little or nothing about the nutritional limitations and requirements of the broiler embryo before hatch. Dr Zehava Uni, professor at the Animal Science Department of the Hebrew University of Jerusalem, told attendees that the fertile egg has a defined nutrients composition. However, the rate and mechanism of ‘eating’ (digestion and absorption of these nutrients) by the embryo during incubation is not clear. The embryo starts to consume yolk nutrients intensively only from mid-incubation on, while intensive consumption of fat from the yolk starts in the last week of incubation. Nonetheless, there is a differential uptake of yolk nutrients during incubation. This uptake is dramatically influenced by the hatchery conditions, said Dr Uni.

Research has shown that during the last days of incubation, the levels of phosphorus, iron, zinc and copper in the yolk are low. These minerals are consumed from the yolk and leave the embryo as of day 17 without an external source or minerals for at least six days. This may impair the embryonic and hatchling development, which may lead to leg and skeletal problems and an immature immune system in rapid growing strains. These problems can, according to Dr Uni’s own investigations, be prevented by providing the lacking nutrients by supplementing them to the breeder hen diet or by means of in-ovo feeding at day 17 of incubation.

Look at birds and respond early
One of the major problems in broiler breeder nutrition today is energy! Energy is a fundamental entity of nature that is transferred between parts of a system in the production of a physical change within the system. Our lean meat birds have no fat to rely on when something goes wrong. With these words, Dr Michael Hellwig, director of nutrition at Pilgrim’s, the world’s largest broiler company with its headquarters in the USA, started his presentation 
on ‘Latest Trends in Broiler Breeder Nutrition.’

“In the US we have houses without heating. When the temperature is low, we rely on the birds capability to maintain their own body temperature and support them by feeding energy (2% extra). During hot weather, we cool the houses and want to keep feed energy low. Feed formulation therefore cannot be separated from feed management,” said Dr Hellwig. “But watch the bird!” he reminded attendees. “And take action a couple of days prior to weather changes, because responding later is asking for problems.” According to Dr Hellwig, if the average house temperature (hens are comfortable at 65°F/18°C) is expected to drop below 63°F/17°C provide 28 kcal/bird/day beginning two to three days before the expected temperature drop and 46 kcal in case the temperature drops below 57°F/14°C.

Dr Hellwig strongly advised breeder managers to maintain the bird’s feather condition. Not only to better control body temperature but to also protect their skin from damaging during mating. It is his opinion that breeder managers should look at the bird based on how she responds to the feed she is offered and try to be ahead of possible deficiencies or problems. During rearing weight gain from 16 to 20 weeks should be 33% and from 20 to 25 weeks about 900 gr. If birds are behind additional feed should be given, but do not provide excessive amounts of feed, Dr Hellwig warns. He recommends to delay moving pullets below target weight by one week, so they can catch up. In addition, he cautions to be sure to avoid drastic feed increases and assure a steady growth. Hens getting on peak too soon results in peritonitis, which results in health 
problems, a loss in impact of medication and an increase in mortality.

More healthy chicks per hen housed
Trace minerals are essential in the nutrition of all living species, including broiler breeders. Deficiencies affect their performance and health. Each of the major trace minerals has its own function, provided that they are properly absorbed and given at the right amount.

These amounts may differ according to the recommendations for the breeder lines, said Dr Marco Rebollo, Poultry Research Specialist, Zinpro Corporation, during his presentation. Most important, according to Dr Rebollo, is the use of Performance Minerals which are a unique, research-proven form of trace minerals that are highly available to the animal. These trace minerals are known for the excellent uptake by the digestive system.

Research has shown that, according to Dr Rebollo, the combined use of Zinpro Performance Minerals (Availa Zn and Availa Mn) have a positive effect on egg shell quality, hatching egg production, fertility, hatchability, chick production and quality, chick liveability and the functioning of their immune system. 
In addition these essential nutrients play a major role in skeletal development, feather condition and foot pad quality. These attributes are important for broiler breeders because lame roosters do not mate and poor-feathered hens do not like to be mated.

Research in Brazil and Thailand shows that Zn and Mn from Zinpro Performance Minerals (Availa Zn and Availa Mn) also keep egg production in older birds (over 50 weeks) at a higher level. This results in more healthy chicks per hen housed. Zinc is an essential nutrient for males, because zinc deficiency may result in lowered testosterone levels. Zinc stimulates sperm production, but even more importantly, it improves sperm quality and thus, as Dr Rebollo said, overall breeder performance.

Studies also show that feeding this unique form of trace minerals to broiler breeders helps improve embryo bone development, chick length at hatch and progeny immunity. This leads to the conclusion, according to Dr Rebollo, that feeding Zinpro Performance Minerals is an effective and economical way to improve broiler breeder and broiler performance.

Source: World Poultry, Voulme 30, No. 9

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Van Der Sluis