Sklan and Plavnik (Br Poult Science, Volume 43) evaluated the effect of diets with increasing concentrations of crude protein, at either fixed essential amino acid concentrations or at fixed essential amino acid: dietary crude protein ratios, on performance was examined in 1- to 4-week-old male Cobb chicks. Increasing crude protein intakes at constant essential amino acid concentrations was carried out at two dietary energy contents.

Increasing protein resulted in a linear decrease in feed intake while weight gain and feed efficiency changed quadratically with a smaller positive effect at the highest crude protein intakes. Feed intake decreased and feed efficiency increased with higher dietary energy and interactions between protein and energy were significant. Abdominal fat content and the efficiency of protein retention decreased with increasing dietary protein intake.

Using constant essential amino acid: crude protein ratios at increasing crude protein intakes, resulted in feed intake, weight gain and feed efficiency all increasing before reaching a plateau. Abdominal fat decreased with protein intake and the efficiency of protein retention was quadratic, decreasing at the higher protein intakes.

Multiple regression analysis of the results of these trials indicated that partition of energy intake into maintenance, fat-free tissue growth, fat and the energy required to transform protein intake in excess of retention explained more than 98% of variation. It is proposed that either non-essential amino acid or essential amino acid intake limited broiler performance at the lower protein intakes, whereas at high protein intakes the decreased efficiency of amino acid utilisation after growth requirements are fulfilled, resulted in poorer performance.

It was concluded that these results support the general principle that diets should be formulated to provide sufficient of all AA for protein synthesis and that excess AA should be avoided, as this decreases the efficiency of utilisation and also increases the essential AA requirements.

Li, Berry and Oates of Auburn Universities Department of Poultry Science published work on the use of phytase in broiler breeders. Little information is available about whether phytase can be used to replace phosphorus in rearing and production diets of breeder replacement pullets and hens. The objective of this study was to quantify the effects of dietary phytase on growth and liveability of pullets during the rearing phase and their subsequent production performance during the entire breeder period.

Onethousand day-old female breeder chicks were placed in 4 pens with 250 birds each receiving 2 dietary treatments with 2 pens each treatment in a litter floored light proof pullet house. Male chicks were reared separately. Control pullets received a diet with 0.35%AP added inorganic phosphorus. Phytase treated pullets received a diet with 0.25%AP, supplemented with 300 U/kg phytase. At 22 weeks of age, 800 pullets were allocated to 8 pens in a curtain sided, slat litter breeder house. There were 100 hens per pen. Four pens each received either a control diet containing 0.3%AP without phytase or a phytase diet containing 0.1%AP supplemented with 300U/kg phytase. In the first 22 weeks, there was no significant difference in mortality, body weight or weight uniformity between control and phytase treatment groups. Every 4 weeks, 40 birds from each treatment were measured for shank and keel length and 4 birds from each treatment were killed for measurement of digestive tract length including large intestine & ceca, small intestine, pancreas and gizzard. Blood samples were taken from 40 hens in each treatment to determination of plasma total protein, calcium and phosphorous. Litter samples were taken for determination of litter phosphorus.

Twelve 27-kg (SE = 0.8) barrows were used in Exp. 1 to measure the apparent faecal digestibility of DM, GE and N of de-germed, de-hulled corn compared with corn grain. Two diets were formulated to contain either 96.4% of de-germed, de-hulled corn or corn grain plus supplemental vitamins and minerals. Digestibility of DM, GE, and N was greater in de-germed, de-hulled corn (96.2, 96.0, and 93.6%, respectively) compared with corn grain (89.0, 89.0, and 78.4%, respectively) (P < 0.01). Overall, a 67 and 29% reduction in DM and N excretion, respectively, was observed.

In Exp. 2, eight 70-kg (SE =1.8) barrows were surgically fitted with ileal cannulae and fed the same diets as in Exp. 1, to measure the ileal digestibility of nutrients in de-germed, de-hulled corn. Ileal digestibility of DM, energy, and N was 13, 15, and 7% greater in de-germed, de-hulled corn (P < 0.05). Apparent ileal digestibility coefficients of leucine, methionine, and phenylalanine were greater in de-germed, de-hulled corn compared with corn grain (P < 0.05) while a trend for a lower tryptophan digestibility in de-germed, de-hulled corn was observed (P = 0.067).

In Experiment 3, 96 nursery pigs with an initial average BW of 8.8 kg (SE = 0.08), fed a starter diet formulated with de-germed de-hulled corn or corn grain as the major grain source, were used in a 28-d growth performance study. At the end of the study, 24 pigs (1 pig per pen) were sacrificed and gastrointestinal tract measurements were taken. Daily growth rates of pigs were the same between diets (0.64 kg/d). A trend for reduced feed intake (P = 0.073) in pigs fed de-germed, de-hulled corn led to a 4% improvement in gain to feed (P < 0.05). Feeding de-germed, de-hulled corn had no effect on gut fill, gastrointestinal tract weight, or liver weight (P > 0.05). Ileal villus lengths and crypt depths were not affected by feeding de-germed, de-hulled corn although ileal villus widths were greater in pigs fed corn grain. Results from these trials suggest that corn processed to remove poorly digestible fibre fractions provides more digestible nutrients than corn grain. As a result, de-germed, de-hulled corn reduces faecal and N excretion, thus providing a means to reduce nutrient excretion.

Results from this study suggest that processing corn to remove poorly digestible fibre fractions significantly improves the digestibility and retention of energy and nitrogen. In addition, reductions in dietary fibre content via addition of de-germed, de-hulled corn to pig nursery diets improve feed efficiency by 4%. The use of de-germed, de-hulled corn in pig diets has potential to greatly reduce faecal and nitrogen excretion, thus providing a potential means to reduce the negative environmental impacts of intensive pig production. Future research should focus on the effects of de-germed, de-hulled corn on nutrient excretion when incorporated into a complete feed and the long-term health effects of feeding this product to pigs, specifically the potential occurrenc of gastric ulcers.

The occurrence of blood spots in eggs is a problem that rears its head every so often. It remains a problem on a particular farm for a while then disappears as quietly as it arrived.

Some of the possible causes of an increase in bloodspots are listed below.

Grasso Ebako

The most recent edition of Avian Advice (Volume 5, Number 1) edit by Frank Jones the Extension Leader for the University of Arkansas Poultry Science department has proved to be a gold mine of useful information. I have included the summaries in this newsletter but visit the site at www.uark.edu/depts/posc/avianindex.html

Measuring flock uniformity is undoubtedly an important tool when evaluating the success of a pullet program. When a flock leaves the pullet house with a great deal of variation in body weight a series of conditions can often be expected to occur. The flock will often come into egg production slowly, since a disproportionate number of hens are not ready to produce eggs at the time of lighting. Early hatchability will also be less than expected because there will be an increase in early embryo mortality from those eggs laid by the lighter weight hens that mature slower. The flock, as a whole, will likely not attain the egg production peak expected because many of the hens are being either over or under fed at this crucial time in the production cycle. Finally, egg size will often continue to show considerable variation throughout the life of the flock which will not only reduce hatchability but may also affect the quality of the chick produced. Just how important is flock uniformity? Or should we be asking, what is more important than flock uniformity?

Understanding the eating behaviour of pigs can help producers maximise feed intake and, as a result, promote improved pig performance. Dr. Harold Gonyou, a scientist at the Prairie Swine Centre, Inc., in Saskatoon, Canada, studies behaviour in swine and provides some insight into the importance of understanding behaviour and how we can benefit from this.