Characteristics of the Hy-Line Brown by Levone


									                                   Characteristics of the Hy-Line Brown

          Successful production of a commercial layer, as well as customer satisfaction, require concerted effort, on
the part of the breeding company, in a number of different areas:
          - Conscientious sales staff for customer contact and to address customer questions and concerns
          - Expert technical service to advise producers on management and nutrition
          - Reliable production of the commercial product
          - Development and continuous improvement of a high quality product
          - Ownership and administration with understanding in all these areas, commitment to the business and to
            customer satisfaction, and vision for addressing current needs and anticipating or developing future
          Hy-Line International’s pursuit of excellence in each of these areas is evidenced in part by a current market
share of approximately 85% in North America. Worldwide market share is difficult to determine because of
unknown layer numbers in some parts of the world. A reasonable estimate of Hy-Line’s worldwide market share,
though, is 25 to 30% and Hy-Line’s international sales continue to grow.
          Hy-Line currently sells seven commercial varieties. Three of these varieties, however, constitute the
majority of Hy-Line sales: the W-36 and W-98, which are white egg varieties, and the Hy-Line Brown, its major
brown egg variety. This paper will focus on the Hy-Line Brown, its performance and key management points for
both the growing and laying periods. The Hy-Line breeding program, which determines the future characteristics of
the variety, will also be described.
          With reasonable management and nutrition, the Brown is a relatively problem-free bird with good
production and shell color, excellent livability, and good shells. Perhaps most importantly, it holds production, shell
strength, and shell color well throughout lay which, combined with its livability, translates to a long and profitable
productive life. It is also a very calm bird with little tendency for cannibalism which makes it particularly attractive
for floor and free range systems.

Growing Period
          In commercial operations, Hy-Line Browns average 96 to 98% livability during the growing period. In
general, the pullets can be grown equally well in cages or on the floor. While it requires no special management,
there are several key management points to maximize livability and performance in the laying house. Day old
chicks need to be brooded at temperatures of 35 to 37 degrees Celsius (95 to 99 o F) with 40 to 60% humidity.
Temperatures may need to be modified according to humidity. Chicks will spread out away from the heat source if
they are too hot; they will huddle together, generally closer to the heat source, if they are too cold. Temperature
should be reduced 2o C (4o F) per week until 21o C (70o F) is reached.
          Body weight is an important characteristic of the young pullet. Inadequate growth between hatch and 12
weeks generally results in less egg mass in the laying house. Too much gain after 12 weeks of age results in excess
fat deposition which, in addition to poorer performance, can lead to other metabolic problems. Weekly target body
weights can be found in the Hy-Line Brown management guide. Briefly, at 6 weeks of age pullets should be
weighing about .48 kg; at 12 weeks of age about 1.05 kg; and at 17 weeks about 1.43 kg. Exceeding the target
weights up to 12 weeks is acceptable but weights should not be more than 20g below target during this time.
Growth lost during the first 12 weeks cannot be compensated for later on. The body weight targets for the Hy-Line
Brown pullet are obtained fairly well in most environments and management systems. If weights are consistently
more than 20g below target, it would be worthwhile to examine the nutritional program as well as other management
factors to try to ascertain a cause and bring the body weights more in line with published standards.
          Other management practices for the Hy-Line Brown are standard for the industry. One beak trimming at 7
to 10 days of age is recommended. Lighting and vaccination schedules for the growing period, as well as nutritional
recommendations, are fairly standard and are outlined in detail in the Hy-Line Brown management guide. Because
of its egg mass and relatively early maturity, one key nutritional point to emphasize is making pre-lay ration
available at least 3 weeks prior to the onset of lay. This will ensure adequate calcium as the bird reaches sexual
maturity and deter bone problems later in lay.
Laying period
          Table 1 summarizes the performance of the Hy-Line Brown layer. Values in table 1 are based on field
data. The Brown reaches 50% production, on average, at 20 to 21 weeks. It peaks at 94 to 96% and it can be
expected to have 252 hen-day eggs at 60 weeks and 357 hen-day eggs at 80 weeks.
          Egg weight averages 62.7g/egg at 32 weeks and about 67g/egg at 70 weeks. The Hy-Line Brown will
respond to measures for controlling egg weight. However, such practices must be initiated prior to achieving the
target weight. For example, if a 60g maximum egg size is desired, decreases in methionine and control of feed
consumption need to start when egg weight reaches 58 g/egg.
          The Hy-Line Brown has excellent laying livability, averaging 96% at 80 weeks. Shell color is dark,
relatively uniform, continues to improve and, like shell strength, is well maintained throughout lay. Feed
consumption averages 113g/bird/day between 18 and 80 weeks. Mature body weight is a uniform 2.0 kg.
          Like the pullet, the layer requires no special management although there are a few key points to emphasize
to ensure optimum performance. The recommended age for housing pullets is 17 weeks. The optimum time for
light stimulation appears to be around 1.43 kg (17 weeks). Rations should be formulated to ensure adequate Ca,
especially during peak. Adult body weights should not exceed 2.1 kg. House temperatures might be raised to 26 o
and/or lower energy diets utilized to control body weight if monitoring indicates excessive gains.

Breeding Program
           Modern layer hens are not the same as layer hens of 20 or 30 years ago or even 10 years ago. Production
and livability, for example, have risen dramatically over the last several decades. Although part of this has been due
to improvements in management and nutrition, chickens have changed genetically as well. Even under constant
environmental conditions, changes in layer performance could be observed. Designed breeding programs have
brought about these changes and these breeding programs continue to be carried out today with the aim of even
further improvement. When considering a variety, then, it is important to consider the breeding program, as it is this
that determines future characteristics and expectations for the layer.
           The Hy-Line Brown, like all Hy-Line varieties, is produced from a 4-way cross of pure lines. These pure
lines are under constant selection for all economically important traits. Selection is the “tool” that brings about
genetic improvement and selection is simply a matter of breeding from, and only from, the genetically best birds in
the population. For example, if a population consists of 1000 hens, the geneticist would use, say, only the 100 best
of these hens to produce the next generation; that is, only 100 hens to breed from. An important aspect of selection,
then, is determining which birds are the best ones and there is no magical way or “secret formula” for determining
that. The breeder must allow the birds to mature, collect records on each trait of importance, and use those records
to determine which birds are genetically the best and should be used for breeding.
           One important feature of the Hy-Line breeding program is the sources of data used for selection. Hy-Line
has two sources of data. One is records on the pure line birds which are housed in one central location called the
Research Farm. A second source is data from a field test, using multiple locations, where birds are housed in actual
commercial houses. Both data sets are valuable sources of information. The records on the pure line birds
constitute a relatively large set of data, on individual birds, with high accuracy, and complete pedigrees. The
Research Farm, however, is a specialized environment. Adult birds are housed in single bird cages to allow for
individual data collection and it has much tighter biosecurity than most commercial operations. If selection were
made entirely on these records, it might lead to a bird that performed very well under those conditions but not so
well under commercial conditions. For the field test, each pure line sire is mated to cross-line dams and their chicks
are placed in group cages in actual commercial operations where records on production, livability, and egg quality
are collected. No special management is afforded to these birds.
           Hy-Line varieties are perhaps best known for their livability and freedom from cannibalism. The long-term
use of the field test can be credited with development of these characteristics. Another important feature of the field
test is that, to a large extent, it automatically adapts to changes in the commercial environment. For example,
whatever disease challenges face the commercial population, face the field test birds as well and only birds whose
relatives survive well will be selected.
           The primary traits under selection in the Hy-Line breeding program are:
                      - Albumen height                     - Shell Color             - Egg Weight
                      - Production                         - Shell Strength          - Sexual Maturity
                      - Feed Conversion                    - Livability              - Temperament
                      - Body Weight                        - Resistance to Marek’s
Each of these traits is selected on each generation in each line. The significance of this is that it brings about a very
well balanced commercial, one that is at least good in all economically important traits. In addition to selection on
Table 1.
                   Capabilities of the Hy-Line Brown
                         Laying period to 80 Weeks

Percent Peak                                             94-96%

Hen-Day Eggs:
  To 60 Weeks                                              252
  To 74 Weeks                                              328
  To 80 Weeks                                              357

Hen-Housed Eggs:
  To 60 Weeks                                              249
  To 74 Weeks                                              323
  To 80 Weeks                                              351

Livability to 80 Weeks                                    96%

Days to 50% Production (from Hatch)                     145 Days

Egg Weight at 32 Weeks                                  62.7 g/Egg
                                                     (49.8 Lbs./Case)
Egg Weight at 70 Weeks                                  66.9 g/Egg
                                                     (53.1 Lbs./Case)

Total Egg Mass per Hen-Day:
   18-74 Weeks                                           20.9 Kg
                                                       (46.2 Lbs.)
   18-80 Weeks                                           22.9 Kg
                                                       (50.5 Lbs.)

Body Weight at 70 Weeks                                  2.00 Kg
                                                       (4.41 Lbs.)

Freedom from Egg Inclusions                             Excellent

Shell Color                                      Uniform, Dark Brown

Shell Strength                                          Excellent

Haugh Units at 70 Weeks                                    80

Average Daily Feed Consumption (18-80 Weeks)      113 Grams/Bird/Day
                                               (25.0 Lbs./100 Birds/Day)

Kg of Feed per Kg of Eggs (21-74 Weeks)                   2.06

Feed per Dozen Eggs (21-74 Weeks)                        1.58 Kg
                                                       (3.48 Lbs.)
* From the 2002-2004 Hy-Line Brown Management Guide.
egg weight alone, Hy-Line also makes selections to affect the egg weight curve in order to enhance the producer’s
ability to control egg weight. The goal is to develop a bird whose egg weight comes up rapidly early in lay but then
is easily leveled off. This is accomplished by measuring egg weight both “earlier” in lay and “later” in lay and then
selecting for hens whose egg weight shows little change between the two time periods.
           Another important feature of the Hy-Line breeding program is direct selection for performance later in lay.
Records on the field test birds are kept through their entire lay cycle and recording of production on pure line hens
extends to 60+ weeks. This provides the means for selection on persistency of production, shell color, and shell
strength. The old and new Hy-Line Brown management guides provide a good illustration of the effect of selection
for persistency. Field data is used to set the production standards. Comparing pages 14 and 15 of the 2000-
2001guide to the same pages of the updated, 2002-2004 guide indicates an increase of 3.1 hen-day eggs at 80 weeks.
This was a 1 egg increase in production up to 50 weeks and a 2.1 egg increase past 50 weeks. The field records
clearly indicated improvement in persistency of lay.
           Responsible implementation of any type of program in any type of business requires monitoring that
program for effectiveness. A breeding program is monitored by checking whether or not genetic progress is in fact
being made and if so, how much. Based on pure line performance to 35 weeks, the Hy-Line Brown has improved,
over the last 5 years, a total of 0.26 mm in albumen height, 4.6 units in shell color, 1.6g in egg weight, 3.5%
production, 5.4 in egg number, 18.2 g in shell strength (measured by a “puncture score” = amount of pressure
required to puncture a small hole in the egg shell with a blunt needle), and reaches sexual maturity 2.7 days earlier.
These are actual, realized genetic gains, not “targets” or predicted gains. Note for emphasis and clarity that these
results are based only on data to 35 weeks. Percent production and egg number cannot be linearly extrapolated to
the end of lay due to decreasing production later in the lay cycle. The main point here is simply that the numbers are
positive; the Hy-Line Brown is improving.
           Clearly, the current breeding program is effective. Nonetheless, new ways to make even more rapid
progress are always being sought. A relatively new aspect to breeding programs worldwide, in all species, is
molecular genetics or “gene mapping.” Identification of molecular markers will enhance selection, especially for
traits that are difficult or expensive to measure, such as egg solids traits, and traits that are measured later in life such
as persistency. Hy-Line started its own in-house molecular biology program in the 1990’s. We are currently in the
first stage of a molecular biology program which is identification of markers in primary traits.
           Another relatively recent change in the breeding program has been basing selection on best linear unbiased
predictions (BLUP) of breeding value. This methodology is considered state of the art for genetic evaluation and
has provided a rigorous framework for simultaneous use of the field test and pure line data. This makes the most
efficient use of the available data and maximizes accuracy of selection. This is expected to have a noticeable effect
on the amount of genetic progress per year.
           In addition to the primary traits listed previously, there are several important qualitative characteristics of
Hy-Line varieties as well. In the 1980’s, Hy-Line implemented a program to completely eradicate lymphoid
leucosis (LL) and today, all Hy-Line varieties are LL-free. Another qualitative characteristic that Hy-Line makes
use of is blood type. Different blood types have been fixed in different lines which allows identification of lines by
blood type. This is one tool used by Hy-Line’s production department to ensure correct matings for production of
the commercial layer.

          Hy-Line International is a strong, well established company committed to providing its customers with the
best quality bird possible. This paper focused on Hy-Line’s primary brown egg commercial, called simply the Hy-
Line Brown. The Brown’s strongest characteristics are perhaps its livability and very docile, non-cannibalistic
nature. It also has good shell color and shell strength but perhaps most notably maintains these characteristics well
throughout lay. This, along with its livability and persistency of production, provides for a bird with excellent
longevity which, in turn, makes the Hy-Line Brown a profitable commercial layer.
          The breeding program is an important part of any commercial variety as it determines the future
performance of the variety. One key aspect of the Hy-Line breeding program is its use of field data for selection.
This is especially important for improved livability. The field test also, to a large extent, “automatically” adapts the
breeding program to changes in the commercial environment. Another significant aspect of the breeding program is
direct selection for performance later in lay which, as indicated by field records, has been effective.
          Perhaps the most important aspect of the Hy-Line breeding program is a constant striving for improvement.
This ranges from minor day to day improvements in data collection and data management, to better utilization of
data, and to larger changes such as implementation of molecular marker information.

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