COOPERATIVE EXTENSION

UNIVERSITY OF CALIFORNIA

CALIFORNIA POULTRY LETTER

September 1998

In This Issue:

• Francine Bradley Wins Prestigious Award
• Nutrient Management Summit
• Management Practices During Pullet Rearing and Their Effect on Adult Flock Performance
• Temperature Variation Within the Egg Cold Storage Room
• The Effect of Temperature and Storage Time on Weight Loss of Table Eggs
• Molting Technologies - Welfare Issues
• Life Without Animal Research

Francine Bradley Wins Prestigious Award

Congratulations, Francine!

Francine Bradley, Extension Poultry Specialist at U.C. Davis, has been named the first recipient of the Poultry Science Association's Helene B. Cecil Award. Established in memory of Dr. Cecil, a poultry scientist at USDA, Beltsville and the first female president of PSA, the award is for sustained scientific contributions in the field of poultry science and for significant leadership in the promotion and development of opportunities for women in the area of poultry science.

Bradley was recognized for her long time commitment to encouraging girls considering careers in poultry and for mentoring and promoting female college students and academics. Some of her activities in this area include Expanding Your Horizons, Adopt-a-Scientist, Ag in the Classroom, the U.C. Davis Pro Femina Research Consortium, Capital Agri-Women, and Special Symposia on Women at the XIX and XX World Poultry Congresses.

Announcement of the award was made at the Annual Meeting of PSA held August 5th at Penn State University. Mr. Bill Cecil presented Bradley with a plaque and the $3000 prize.

Nutrient Management Summit

What are the California regulations pertaining to poultry and the environment today? What will happen if your farm does not comply? Who can help you meet the environmental regulations?

These are just some of the topics to be discussed in a meeting sponsored by the California Poultry Industry Federation on Thursday, September 24, 1998. The meeting will be held at the Doubletree Hotel (the old Red Lion Inn) between 8:30 a.m. and noon in Modesto and is intended for all growers, managers and owners of poultry (meat and eggs) in California. Speakers include:

• Richard Cutler, Assistant US. Attorney
• Rudy Schnagl, Regional Water Quality Control Board
• Dr. Richard Breitmeyer, Director and State Veterinarian, Animal Health & Food Safety Service, California Dept. of Food and Agriculture
• John Voris, University of California, Cooperative Extension Turkey Specialist
• Dr.. Joan Jeffrey, University of California, Cooperative Extension Poultry Veterinarian
• Dr. Ralph Ernst, University of California, Cooperative Extension Poultry Specialist

Pre-registration is required. Send check or money order for $20, payable to California Poultry Industry Federation or phone for reservations: (209) 576-6355.

Enclose your name, address and phone number. Mail to:

Poultry Nutrient Management Summit
3117 Suite A McHenry Avenue
Modesto, Ca 95350

Management Practices During Pullet Rearing and Their Effect on Adult Flock Performance

When layer flocks fail to perform up to previous standards or the target levels of the breeder, producers generally take a hard look at "what's happening right now" for answers or areas to correct. It's difficult to correlate something that happened 6 months ago to today's problems.

When a flock starts out properly in the layer house with egg production on schedule, low mortality rates and decent egg size, the chances are very good that the rearing program was a success. If on the other hand, egg production is delayed, eggs are small in size and weekly mortality rates are in excess of .15% per week and increasing, then something is definitely wrong and it probably can be traced back to errors in the rearing program. Sudden dips in egg production curves or departures from trend lines, on the other hand, are most often the result of "current" errors in management.

What are some of the errors that might have occurred during rearing that could result in sub-optimal performance 3 to 6 months later?

1. Health problems which may result in low body weights, or skeletal/organ damage. Poor immunity due to faulty vaccination programs may leave the flock susceptible to disease problems later on.
2. Faulty nutrition can affect housing body weights and result in abnormal nutrient intake. This could result in over-weight pullets which tend to over-eat for the remainder of their lives and have excessive egg size or underweight pullets which never have enough capacity to produce normal egg mass.
3. Crowding can result in low body weights and high degrees of non-uniformity. This results in management difficulties and in over- and under-feeding problems.
4. Improper lighting programs which may affect early lay and/or egg size.
5. Poor beak trimming techniques may permanently affect the bird's ability to eat, result in excessive picking, or affect body weights to the extent of reducing production or egg size.
6. Lack of adequate eating, drinking or living space may result in poor flock uniformity.

Several recent papers have shed new light on several of these problems. Dr. K. Keshavarz from Cornell Unversity has just published an excellent paper showing the combined effects of cage floor space during rearing, protein and energy levels in pullet feeds and light management in the brood-grow house.

In the first experiment Dr. Keshavarz compared 9 vs 11 birds in 24.4 in. wide x 20.4 in. deep cages during the 8 to 18 week period. Pullets were transferred to lay cages at 18 weeks and kept under common management until 38 weeks of age. (Table 1)

Both of these space allowances are above the normally recommended levels of the major breeders. Even though all but the 12 week body weights were statistically different, the different space allowances had practically no effect on the birds later on in their lives. Costs to produce an 18 week pullet, though, would have been about 2.5 cents more for the birds with the 55 square inch space allowance.

Table 1. Effects of floor space allowance, protein and energy levels during rearing;treatments during weeks 8-18; layer performance during weeks 18 to 38.

(Note: results in the same row and treatment with the same letter are not significantly different).

These results demonstrate the adequacy of both floor space allowances. In practice, though, some producers may give their pullets less than the 45 square inches provided in this experiment and performance may be affected.

A second aspect of Dr. Keshavarz's research compared two energy levels of the diet - 1280 and 1380 kcal per pound. These, in general, bracket the commonly used energy levels within the commercial pullet rearing industry.

Even though there were significantly different body weights, once again, no important differences were noted in performance.

Slightly less feed was required for the higher energy diet and this would have given slightly different costs.

And finally, in experiment 1, two different levels of protein were fed during the 8 to 18 week period - 14.5% and 17.5% protein. This was proceeded with a 21% starter feed for both groups and followed with a 16.5% layer diet from 18 to 38 weeks of age.

All body weights and feed consumption were higher in the groups fed the 17.5% diets., but there were no significant differences in performance during this fairly short experiment.

This experiment does not rule out the possibility of adverse effects of limiting space, or dietary energy and protein levels - even within the ranges tested. Other factors present in commercial situations may increase or decrease results including strain of birds used, seasonal conditions, temperature, beak trimming or any factor affecting feed consumption. Also, when various performance factors are given economic values, the net effect may be totally different and these results may be statistically significant.

Certain trends were present in this data indicating the possibility of more drastic effects at greater extremes. For example, other researchers have demonstrated 1/4 pound decreases in body weight with 36 to 40 square inches of floor space to 20 weeks - significantly less space than tested in this experiment. Others have used diets as low as 10% protein for the grow period (12 to 20 weeks) with fairly minimal , but increasingly important, effects on performance in the lay house.

A second experiment (in this same paper) compared lighting programs, dietary energy levels, and two protein feeding programs.

• Step-down vs short day lighting
• 1280 vs 1380 kcal ME/lb. energy levels
• 18%-16%-14% vs 22%- 18%-16% protein feeding programs

After an initial 2 days of 23 hours/day lighting, the step-down lighted birds were reduced 1 hour per week until the 16th week when they reached 8 hours of light per day. Lights were then held constant at 8 hours through the 18th week. The short-day lighted birds received 23 hours of light per day for the first 2 days and then 8 hours/day to 18 weeks. Both groups were given 13 hours of light per day during the 19th week with 30 minutes/day increases until they reached 16 hours/day.

Protein levels were fed as listed above during the 0-6, 6-12, and 12-18 week periods respectively. Dietary energy remained at the levels listed above during the entire rearing period. At 18 weeks all diets were changed to a 16.5% protein level with 1312 kcal ME per pound.

Table 2 compares each of the three main treatment effects for various performance traits. Lighting had the most effect on performance of the three main factors. The short-day program (8 hours per day until 18 weeks) resulted in significant body weight depression through the 15 week weighings. High energy levels had no significant effect on body weight while higher protein levels gave higher body weights.

Feed consumption per pullet to 18 weeks was about .7 pound per bird less in the short-day program. Significantly less feed was also used with the higher energy and higher protein diets.

High protein improved early egg production rates but not overall production. Eggs per hen housed to 66 weeks of age were practically identical for the various dietary energy and protein levels. All other measurements were basically unaffected.

Short-day lighting programs resulted in a 9.7 day earlier age at 50% egg production and significantly higher early and overall egg production. Eggs per hen-housed to 66 weeks favored the short-day program by 18 eggs (265 vs 247). This was associated with practically no difference in feed consumption (short day - 25.5 pounds/100 hens/day vs 25.7 pounds/100 hens/day for the step-down treatment). Egg size was not different in early stages of lay, but overall differences slightly favored the step-down lighting program. Analysis of egg weight categories showed that the step-down lighted birds produced about 5% more large and above eggs and as a result, significantly fewer medium eggs.

Table 2. Effects of lighting program, protein and energy levels during rearing; treatments during weeks 0-18); layer performance during weeks 19 to 66.

Summary: The two experiments gave remarkably similar results for dietary energy and protein comparison. Very few effects of either treatment carried over into the layer phase.

On the other hand. the lighting programs showed major differences in the lay house. Eighteen more eggs in the short-day program (constant 8 hour lighting) with practically the same egg size and feed consumption would be an economically strong incentive for commercial egg producers to investigate similar lighting programs.

These experiments were conducted in windowless houses which were essentially light-tight. Light intensity was maintained at a minimum of « ft. candle during the lighted periods of the day. The potential for the full application of the lighting portions of this experiment depends upon the nature of light control in the brood-grow house. Is total darkness possible for the 16 hour dark period of each day? Obviously, such management techniques would not be possible in open-sided housing.

Don Bell
Poultry Specialist

Temperature Variation Within the Egg Cold Storage Room

Regulations which require the storage of eggs at or below 45 ⁰ F temperatures will require daily monitoring and records for verification. One of the better ways of recording this information is with the use of some type of "data recording" device which can record at frequent intervals and provide you with a permanent record of room temperatures. Figure 1 illustrates a three day recording of temperatures from 4 data logger sensors. In this example, the sensors were placed in 4 different locations throughout the storage room. Data can be collected at any interval of time and data storage capacity in the device is sufficient for several weeks of information. Once the data is collected it can be down-loaded into a computer for analysis or graphing purposes. An entire system of this type can be purchased for less than $100 (assuming you already have a computer). Several commercial companies have similar applications in their software packages.

The graph illustrates the problem of increasing temperatures during the working day with maximum temperatures observed at about 5:00 pm. Temperatures were below the 45 ⁰ F. required temperature during the night and early morning hours, but from noon to 5:00 pm, average temperatures rose above the 45 ⁰ F level.

In addition, two sensors showed higher average temperatures during most of the day compared to the other two. This amounted to a 3-4 degree difference between sensors. and was strictly a location effect. As a result, these two sensors were above the requirement 60-80% of the time, while the other two sensors exceeded the requirement only 6-8% of the time - near the end of the work day.

Walk-through inspectors will probably record temperatures during the normal work day and, as a result, will be recording the hottest conditions in the egg cooler.

The egg industry needs to do three things relative to this issue: 1. Equalize the temperature as much as possible within the storage rooms. Installation of circulating ceiling fans will not only help to equalize temperatures, but they will also hasten egg cooling. 2. Reduce the entry of warm air into the cooler during the filling and unloading processes. This means tightening up the leaks into the storage rooms. 3. And finally, encourage regulations that reflect "average" conditions over a 24 hour data collection period. Seek "average" definitions which better reflect the conditions within the storage room than the walk-through system now being used.

Don Bell
Poultry Specialist

The Effect of Temperature and Storage Time on Weight Loss of Table Eggs

Egg weights are not stable under all methods of handling and excessive weight loss may result in underweight and poor quality (large air cells) at some point in the distribution chain. Several previous studies have shown the importance of implementing proper rotation of egg inventories and refrigeration to minimize the loss of weight and to preserve interior egg quality.

A study was conducted in Southern California in 1996 to demonstrate the effects of time, storage temperature, and whether or not the eggs were cracked on weight loss. Processed (washed, oiled and cartoned) eggs were obtained from a commercial egg processing plant. These eggs were from 32 and 113 week old layers and were large and extra large in size. Eggs were held in a 45 ⁰ F commercial refrigerator or at room temperature (72 ⁰ F) for 28 days. All eggs were weighed daily for the first week and weekly to 28 days. Weights were recorded to the nearest one-tenth of a gram per egg.

Processed eggs with refrigeration lost approximately 1% of their initial weight in 7 days compared to a loss of 1.6 to 2.0% in the non-refrigerated eggs during the same period - a doubling of the weight loss. Weight loss remained at about the same relationship throughout the experiment. At 28 days, the refrigerated eggs had lost 3.1 to 4.3% of their original weight compared to 6.0 to 8.0% for the non-refrigerated eggs - also a doubling. Age of the flock appeared to have no effect on the rate of weight loss.

Table 3. Egg quality measurements after 28 days of storage.

In all cases, eggs on flats, whether refrigerated or non-refrigerated, lost weight at a higher rate than did the eggs in cartons. Cracked eggs (intermingled with sound shelled eggs) lost weight at 3x the rate of non-cracked eggs. By 28 days, the cracked eggs had lost between 7.1 and 7.6 grams of weight or approximately 12% of their original weight compared to about 2.5 grams of weight or 4% of their weight in the sound shelled eggs. This amount of weight loss represents evaporation of water from the egg resulting in reduced albumen quality and potentially underweight eggs in the market place.

Weighing eggs without tolerances for shrinkage at minimum weight definitions can result in eggs which fail to meet legal standards, especially when storage conditions are poor or prolonged. Rapid attainment of proper storage temperatures, thoroughness of oil coverage and high humidity storage will all delay the loss of moisture and preserve both the quality and weight of the eggs processed.

Note: A copy of the more complete version of this report is available from the author.

Don Bell
Poultry Specialist

Molting Technologies - Welfare Issues

Public concern about the welfare of farm animals has resulted in the re-evaluation of care practices recommended for table egg chickens and in some countries, restrictive legislation has been the result. Areas of greatest concern to the table egg industry include housing laying chickens in cages, beak trimming and induced molting.

1967 to 1996 period, the University of California has actively studied alternative techniques in hopes of finding suitable methods which were equal or superior to the more traditional feed withdrawal methods. Over 20 experiments have been conducted with comparisons of 125 different methods of molting. Our objective in conducting these experiments was to evaluate the performance results, condition of the birds, and economic returns associated with the different materials. Many unique differences exist between the methods studied and these should be considered when selecting a method. These include simplicity, cost, mortality , rate of return to production, egg quality at the end of the laying cycle, and the public's perception of the technique. Traditional molting techniques, which involve feed removal, have been severely criticized by welfare groups. As a result, a variety of alternative methods have been studied by various researchers and in many cases these alternatives have been implemented or , in some cases, mandated by legislation.

A summary of University of California non-feed removal molting experiments with a bibliography of research is available from the author.

Don Bell
Poultry Specialist

Life Without Animal Research

(The following item was published in the University of Florida Poultry Newsletter- July 1998)

Without animal research:

• Polio would kill or cripple thousands of unvaccinated children and adults this year.
• Most of the nation's one million insulin-dependent diabetics wouldn't be insulin dependent - they would be dead.
• Millions of Americans would risk death from heart attach, stroke or kidney failure from lack of medication to control their high blood pressure.
• Doctors would have no chemotherapy to save the 70% of children who now survive acute lymphocytic leukemia.
• More than one million Americans would lose vision in at least one eye this year because cataract surgery would be impossible.
• Hundreds of thousand of people disabled by strokes or by head or spinal cord injuries would not benefit from rehabilitation techniques.
• The more than 100,000 people with arthritis who each year receive hip replacements would walk only with great pain and difficulty or be confined to wheelchairs.
• Newborns who contract jaundice each year would develop cerebral palsy, now preventable through photo therapy.
• There would be no kidney dialysis to extend the lives of thousands of patients with end-stage renal disease.
• Surgery of any type would be a painful, rare procedure without the development of modern anesthesia allowing artificially induced unconsciousness or local or general insensitivity to pain.
• Instead of being eradicated, smallpox would continue unchecked and many others would join the millions of people already killed by the disease.
• Millions of dogs, cats, and other pets and farm animals would have died from anthrax, distemper, canine parovirus, feline leukemia, rabies and more than 200 other diseases now preventable thanks to animal research.

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  Don Bell, September Editor
  (909) 787-4555
  E-mail: don.bell@ucr.edu

  Ralph Ernst, Technical Editor
  (530) 752-3513
  E-mail: raernst@ucdavis.edu