The breeder industry is well aware that management and nutrition of parent stock play a key role in achieving the maximum number of strong and vital chicks with good vitality. Various aspects of parent stock management considerably influence chick quality. Such aspects are: uniformity of female frame and egg weight, female condition (fleshing & fat reserves) at moment of light stimulation (MOLS), vaccination program and quality of the hatching eggs.
By Ing. Winfridus Bakker
World technical support manager
Broiler growers normally don’t like to receive chicks from young breeders. The chicks are smaller and normally with higher first week mortality. It is important for these small chicks to be uniform, which comes from egg and yolk uniformity relating to how we manage hens in rearing.
In the first eight weeks frame uniformity is achieved and from 16 weeks fleshing and fat uniformity is important for good sexual uniformity of the hens. The hens should be as close as possible in size and development throughout rearing.
In figure 1 an average uniformity is observed for the Cobb500 FF breeder tracking the average egg weight and uniformity over an egg packer so that all the hatching eggs of a flock are being traced. As can be seen in this figure, the average uniformity is just below 90% and on average 88% with ±10% spread. This means that chicks hatched from these eggs should have uniformity above 80% at hatch, which is a good number for starting chicks on a broiler farm. At 25 weeks of age the hatching eggs over 50 grams already reach uniformity above 80% and then climb fast to 89% to stabilize.
Female condition at light stimulation
In large integrations it is seen that there is a positive correlation between total feed amount consumed or bodyweight condition of the parent females at the end of rearing (147 days of age) and broiler livability at seven days of age from young breeders.
Parent flocks with not enough nutrient intake or the wrong body condition show the highest first week mortality in broiler chicks in the first 6 weeks of the young parent stock with a negative impact on final broiler results.
Table 1 is an example of how mortality and feed intake (female nutrient intake) can show its effect on mortality in first 7 days of age not to mention the impact on uniformity and final results (body weight and feed conversion).
Breeder companies improve broiler feed conversion in the broilers by enhancing growth rate, selecting for larger portions of breast muscle and reducing total body fat. This body fat is a key component at first light stimulation to obtain:
Getting the right amount of body fat that we can measure through weighing abdominal fat deposition is often not easy to obtain. After 12 weeks – start of puberty — it is important to get the females in the proper condition at specific ages. This condition can be expressed in a fleshing score and a pelvic fat score
One of the problems we see in many companies is that females and males are not handled often enough to evaluate their condition at crucial ages. Many technicians prefer to enter the weekly average bodyweights in the computer program together with feed intake and uniformity without knowing the condition of the hens. Computer data should be supported by what is seen in the house.
High uniformity rates on paper, but low uniformity at bird level, is a problem of insufficient man-to-bird contact. You should avoid competing with other companies, or complexes within the company, for the lowest feed intake in rearing. You reap in production what you do in rearing — and over-restricting pullets or not having hens in the right condition at light stimulation is a huge mistake.
Good enough fat deposition is extremely important but how do we get this?
Below is an example of a flock showing average number of follicles and abdominal fat in a flock at 25 weeks of age. This info can be used to fine tune the feeding program.
Figure 2 shows at 25 weeks 36 females that died in the week having an average abdominal fat pad of 2% – considered a nice ‘cushion’ of energy reserves.
Figure 3 above shows the flock performance to 60 weeks with bodyweight curve of the females and males, egg weights and feed amounts of the flock that showed at 25 weeks of age the 2.0% abdominal fat content and 5.4 follicles on the ovaries.
Repeating the abdominal fat evaluation at several ages in production, it is clear from Figure 4 that hens are losing body fat up to 40 weeks of age and then start accumulating again when feed is not withdrawn further or more energy is supplied to the flock.
Females can mobilize stored fat from 25 to 40 weeks to complement their energy needs. This shows why starting with enough abdominal fat is so important in breeders today. Be careful not to confuse enough body fat reserves at start of light program with a considerable higher body weight (BW). A higher BW not necessarily will give you more fat reserves. One consequence of these lower fat stores at start and in peak production is that feed amounts are not anymore reduced strongly at 10% to 15% rate but now at more moderate levels of 5% to 10% from peak production until the end of production.
Another point that helps to get the proper condition of the hens at 21 weeks of age is to assure that the females grow enough from 16 to 20 weeks of age. In general this should be in the +36% to +40% range. Obtaining these BW gains comes from increasing the feed in this same period in general 6% higher than the objective BW increase. Example: BW increase is 38% then feed increase, applying the Cobb feed specs, should be around 44%.
Conclusion: Have enough fat on the birds (1.5-2% at start of production) for good parent stock performance and good chick quality (nutrient transfer to the yolk).
Vaccination program to protect against local disease challenges
Each area in the world needs a specific vaccination program to deal with the local challenges. These challenges include Newcastle disease (ND), Infectious Bronchitis (IB), infectious Laryngotracheitis (ILT), Salmonellosis, and Colibacilosis. In some parts of the world avian influenza viruses have been present in commercial poultry for over 25 years with vaccination against AI to control it. All these diseases can greatly affect the health of the hen with some having the potential to affect chick quality.
Therefore, one of the main objectives of the breeder vaccination program is to prevent diseases that can be vertically transmitted (trans-ovarian and eggshell contamination) such as Salmonella, Mycoplasma (Ms, Mg), Chicken Anemia and Avian Encephalomyelitis as they can have a big impact on chick quality. Important considerations in a vaccination program are:
Hatching egg quality
With reduction or elimination of antibiotic use in parent stock and hatcheries, the major challenges now are to keep contamination as low as possible in the hatching eggs. Some of the principal areas that need constant attention are:
+ Egg shell quality
+ Egg shell contamination
Good vigorous chicks with excellent livability in the first week and good weights at seven days of age are identified as chicks of good quality. They are produced from parent stock flocks uniform in size and in proper fleshing and fat condition at the moment of first light stimulation.
Having enough abdominal fat in the females at light stimulation and at start of production is a good sign that enough nutrients will be transferred to the hatching egg, benefiting early hatchability and chick vitality.
Vaccination programs in the parent stock should be aimed at vertical transmissible diseases that can affect chick quality and broiler results. Producing first quality hatching eggs, with a low bacterial load, is the final step towards first quality chicks down the road.
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