Wheat Middlings as an Alternate Feedstuff for Laying Hens1

Wheat Middlings as an Alternate Feedstuff for Laying Hens1

Wheat Middlings as an Alternate Feedstuff for Laying Hens 1 P. H. PATTERSON, M. L. SUNDE, E. M. SCHIEBER, and W. B. WHITE Department of Poultry Scienc...

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Wheat Middlings as an Alternate Feedstuff for Laying Hens 1 P. H. PATTERSON, M. L. SUNDE, E. M. SCHIEBER, and W. B. WHITE Department of Poultry Science, University of Wisconsin, 1675 Observatory Drive, Madison, Wisconsin 53706 (Received for publication March 30, 1987)

1988 Poultry Science 67:1329-1337 INTRODUCTION

Surprisingly little information is available regarding the feeding of wheat middlings (WM) to commercial laying hens. Summers et al. (1968) and Moran et al. (1970) evaluated wheat samples and milling fractions for energy utilization and protein quality in young growing chicks; however, neither adult birds nor WM were included in their evaluation. In 1941 Bearse reported that replacement of as much as 50% of mash with "standard millrun" (the bran and wheat flour middlings proportions found in normal milling) did not seriously interfere with the egg-producing ability of hens nor the mortality of their chicks. It would appear that the reluctance to use wheat and wheat by-products in this country stems from the plentiful supply and low cost, on a dollar per kilocalorie ME and dollar per

Research supported by the College of Agricultural and Life Sciences, University of Wisconsin, Madison, Wisconsin 53706.

percent CP basis, of corn and soybean meal. However, in instances when the common feedstuffs such as corn and soybean meal are expensive or unavailable, as might occur with crop failures or egg laying operations located outside the US, then WM could serve as a major feed ingredient. Therefore, our major goal was to explore WM as an alternate feedstuff for laying hens. The objectives of this study were to compare various WM diets with conventional corn-soybean meal diets with respect to laying hen performance and egg quality and to study the effect of a cellulase enzyme addition to highWM diets. Previous research at this university showed that bird growth and feed utilization improved with the addition of cellulase enzyme preparations to fibrous diets of wheat bran, WM, brewers grains, and distillers grains (White, 1982). Lastly, the effect of pelleting high-WM diets was also studied. Earlier work using chicks and roosters showed improvements in gain, feed conversion, and ME from pellet-processing of wheat and wheat by-product type diets (Cave et al., 1965; Bayley et al., 1968a,b; Saunders et al., 1969).

1329

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ABSTRACT Four experiments using 320 Single Comb White Leghorn hens per experiment were conducted to evaluate hen performance and egg quality when high levels of wheat middlings (WM) were incorporated into the diet. In the first experiment, hens were fed diets containing 91% WM in either the mash or pellet form, with or without a cellulase enzyme added. Birds showed a drastic drop in egg production during Periods 5, 6, and 7 (28-day periods) following a production peak of greater than 76% in the 2nd period. Feed consumption was excessive and feed utilization was poor. Pelleting of the diet had an adverse effect on hen livability, whereas hens fed the mash diet were normal. Pellet processing or enzyme additions to the basal diet had no consistent effect that would suggest improved hen performance. In a second experiment, diets contained 89, 43, or 20% WM. Birds fed 89% WM laid fewer eggs, had reduced livability, consumed excessive amounts of feed, and utilized feed more poorly than controls fed corn, soybean meal, and alfalfa meal (CSA). Haugh units (HU) were increased and yolk color was decreased with greater amounts of WM in the diet; results suggest that egg HU may be improved by a reduced rate of lay. In a third experiment, diets contained 43% WM with and without 5% white grease, and 20% WM plus 5% grease. Overall, diet had no effect on production, but hens fed 43% WM without grease ate more feed per day and consumed more feed per dozen eggs produced than controls fed CSA as would be expected. The HU were elevated and yolk color was reduced when the diets contained WM. In a fourth experiment, a 25% WM diet was compared with other conventional diets; production, feed per day, and feed per dozen eggs were similar on all diets. In conclusion, it appears WM can serve as a viable alternative to corn in layer diets when included to at least the 43% level. (Key words: wheat middlings, egg production, Haugh units, dietary level)

PATTERSON ET AL.

1330 MATERIALS AND METHODS

conformed to the following specifications: 14% minimum protein, 9.5% maximum crude fiber, and 3.0% minimum crude fat. This product corresponds closely with IFN 4-05-205. In Experiment 1 all diets contained 91% WM as the sole source of ME and protein. The four treatment diets were: 4.8-mm pellets (P), mash (M), and P and M with the cellulase enzyme (E) Trichoderma reesie added at 12.6 mg protein/kg diet (P + E and M + E). Experiment 2 diets varied in the percentage of WM: 89% (89W), 43% (43W), or 20% (20W) and a corn, soybean meal, alfalfa meal diet served as a control (CSA) (Table 1). Diets used in Experiment 3 contained 43% WM (43W) or 43% WM plus 5% white grease (43WF) and 20% WM plus 5% white grease (20WF). The same control diet used in Experiment 2 (CSA) was again used in Experiment 3. Lastly, in Experiment 4 treatment diets consisted of 25% WM (25W), corn and soybean meal (CS), corn, soybean meal, alfalfa meal and meat scrap (CSAM) and CSA in slightly different proportions to the CSA diet used in Experiments 2 and 3 (22% SM in Experiment 4 vs. 21% SM in Experiments 2 and 3). During the final week of the experiments, body weight was measured on an individual hen basis and livability was calculated: number of treatment hens at beginning/number of treatment hens at t*ie end of the experiment x 100. Analysis of variance was performed on the 28-day period data as a split-plot design, with diet as the whole plot and period as the split plot, using the repeated measures procedure of SAS (1982). Period and diet means were ranked using the least significant difference method. Hen-day egg production percentages were transformed using an arcsin transformation before the analysis was performed (arcsin square root of the number of eggs produced/number of hen days). However, only the percentage values are reported for ease of data interpretation. RESULTS AND DISCUSSION

Measures of Production Experiment 1. All birds produced at normal levels in Periods 1 and 2 of the cycle; however, in Periods 3 through 7 differences were observed as a result of the dietary treatments (Figure 1, Experiment 1). In Period 3, hens fed enzyme (from T. reesie) diets had a lower level of production than birds fed diets without enzyme added (P = .0107). In Period 5, birds fed the P diet produced eggs at a lower rate (26.8%)

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Four experiments, each 11 or 12-(28-day) periods long, were conducted to evaluate hen performance on diets containing WM. In each experiment 320, 20-wk-old Single Comb White Leghorn pullets were weighed and housed the last week in August in 8 floor pens, with 40 birds/pen and 2 pens/dietary treatment. Time was divided into 28-day periods and hen-day egg production and feed consumption were determined after each period. During the laying cycle measure of egg quality including Haugh units (HU, Haugh, 1937), yolk color (Heiman and Carver, 1935), shell deformation, and egg weight were collected from individual hens. In Experiment 2 and 3 egg HU and weights were measured on 2 consecutive days in a 28-day period. Egg weights were recorded in all periods and HU were measured in five different periods. Eggshell deformation was measured twice per period for three periods in both experiments using a 500-g load applied to the large end of the egg. Reproductive performance was evaluated in Experiments 2 , 3 , and 4 using two New Hampshire roosters/pen and measuring egg hatchability, fertility, and percentage hatch. In Experiments 2 and 3, more than 120 eggs/treatment were set from four different periods during the laying cycle. Reproductive evaluations were made once in Experiment 4 across all dietary treatments. Chicks that hatched from these experiments were raised to 3 wk of age in electrically heated battery brooders and evaluated for growth, livability, and nutritional deficiency symptoms. Correlations of period hen-day egg production with egg HU were made in Experiments 2 and 3 for the five periods in which both parameters were measured. Similarly, correlations of egg quality from mature hens (Periods 11 and 12) with number of eggs produced in 12 periods was determined so as not to mask egg quality with hen youth. In Experiments 1 and 2 Shaver Starcross 288 and 288A birds, respectively, were used, and H&N Nick Chicks were used in Experiments 3 and 4. Four treatment diets were used in each experiment (Table 1). Diets were formulated to meet or exceed National Research Council (NRC, 1984) nutrient recommendations for laying hens except for ME and calcium; the latter requirement was met by providing oyster shell ad libitum. The WM used in all experiments were provided by the University feed plant and

2.6 .40

2.5 .36

2,240 15.0 22.8 2.6 .33

2,560 14.7 16.1 2.7 .37

2,780 15.7 10.4 2.5 .36

2,240 15.0 22.8 2.6 .35

2,500 14.9 22.4 2.6 .33

2,800 15.0 15.7

5.0 6.0 1.0 .5 .5 .05 .05

5.0 6.0 1.0 .5 .5 .05 .05

6.0 1.0 .5 .5 .05 .05

6.0 1.3 .5 .5 .05

6.0 1.0 .5 .5 .05 .05

6.0 1.0 .5 .5 .05 .05

6.0 1.0 .5 .5 .05 .05

1,640 14.8 36.1

3.0

3.0

3.0

48.0 16.0 20.0

3.0

30.0 11.0 43.0

(%)

3.0

36.0 10.0 43.0

43W

3.0

67.7 21.0

CSA

3.0

55.0 14.0 20.0

20W

89.0

43W

36.0 10.0 43.0

89W

Experiment 3 3 20WF 43WF

Experimental diets were provided as mash or pellets in Experiment 1; as crumbles in Experiment 2; as pellets in Experiment 3; and as mash

3.1 .30

1,640 14.6 35.5

7.5 .5 .5 .5 .1 .05

91.0

Experiment l

Experiment 2 3

8

7

6

s

4

Nonphytate phosphorus, National Research Council (1984).

Oyster shell and granite grit provided ad libitum to all hens.

NDF = Neutral detergent fiber (Preston, 1985).

Premix provides per kilogram diet: 4,000 IU vitamin A, 500 ICU vitamin D 3 , 1 IU vitamin E, 3.5 Mg vitamin B13 , 1 mg riboflavin, .5 g cho

International feed number 4-05-205, National Research Council (1984).

3 89W = 89% Wheat middlings (WM); 43W = 43%WM;20W= 20% WM;CSA = corn, soybean meal, and alfalfa meal; 43WF = 43% WM plu = 25% WM;CSAM = corn, soybean meal, alfalfa meal and meat scraps; CS ~ corn and soybean meal.

The four basal diet treatments were: pelleted or mash wheat middlings with or without the cellulase enzyme Trichoderma reesie added Biochemical Co. Ltd. Nishinomiya, Japan).

2

1

Corn Soybean meal (44% protein) Wheat middlings4 Alfalfa meal Meat scrap White grease Calcium carbonate Dicalcium phosphate Iodized salt Vitamin, mineral, amino acid premix5 L-Methionine L-Lysine HC1 Calculated analysis: Energy, kcal ME/kg Protein, % NDF, %« Calcium, %' Phosphorus, %8

Ingredients

2

TABLE 1. Experimental diet composition1

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PATTERSON ET AL.

during Periods 6 and 7 was only 60 and 72% of the suggested intake estimate for egg-type hens (319 kcal ME/hen per day; NRC, 1984). House temperatures were also the coldest of the year during these periods, because the building was not heated and environmental temperatures during January and February (Periods 6 and 7) were -5.9 and -3.2 C, respectively. The return to production observed in the spring (Periods 8 to 11) can most likely be explained by warming temperatures, increased ME intake to 84% of NRC (1984) recommendations, and completion of the molt. The satisfactory production rates during Periods 2 to 4 and 8 to 11 correspond to an average intake of 279 kcal ME/hen per day. Litter conditions were noticeably wetter in all experimental pens where the 91% WM diet was fed. These pens where 91% WM was fed required litter changing more frequently than other pens in the wing where birds were fed conventional CSA diets. Experiment 2. In the second experiment hens

EXPERIMENT 1

EXPERIMENT 3

>c

^

^

^ = 5 ^ :^S • - 43W •o- 43WF I- 20WF I- CSa =F= 10

PERIOD (28 DAYS)

PERIOD (28 DAYS) EXPERIMENT 4

EXPERIMENT 2

Q O a: a.

so

O

40

O •- cs

< a

o - CSA

20

• - CSAM

z 10

PERIOD (28 DAYS)

11

12

U X

a - 25W 1

10 3

4

5

6

7

8

9

10

PERIOD (28 DAYS)

FIGURE 1. Hen-day egg production (%) measured during 28-day periods of the laying cycle for Experiments 1 to 4 with various diet treatments. For Experiment 1, P = pellet, M = mash, and E = addition of the cellulase enzyme Trichoderma reesie. For Experiments 2, 3, and 4, W = wheat middlings; CSa = corn, soybean meal (21%), and alfalfa meal; WF = wheat middlings + 5% white grease; CS = corn and soybean meal; CSA = corn, soybean meal (22%), and alfalfa meal; and CSAM = corn, soybean meal, alfalfa meal, and meat scraps. •Significant period production differences (P-C.05). **Significant differences (P<.01).

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than any other dietary treatment and suffered an extensive molt. During Periods 6 and 7, all treatments experienced a drop in production and considerably more molting than normal. Hens fed the P and M + E diet had a lower production level over the entire 12 periods than those fed M (Table 2). However, there was no significant effect of pellet processing or cellulase additions on mean production rate for the entire cycle. Birds fed the pelleted diets consumed more feed per dozen eggs (3.53 kg) than those fed mash (3.21 kg) (P = .0102). The loss of production observed in this experiment during the winter months of December through March (Periods 5 to 7) was most likely caused by lower house temperatures, the low energy density of the 91% WM basal diet, and the ensuing molt of the hens. During Periods 6 and 7 a majority of hens was experiencing some degree of feather drop. This coincided with the decrease in production and feed consumption observed at this time. Average energy intake

1333

WHEAT MIDDLINGS AS AN ALTERNATE FEEDSTUFF

at a reduced rate of 48.8% for the entire cycle (Table 2). Feed consumption was elevated and feed utilization was poor for hens fed the highest level of WM (89W). Feed consumption rates were similar in the 20W and CSA treatment groups, whereas the 43W and 89W-fed hens consumed more feed. Once again, the litter required more frequent changing in the pens where birds were fed the highest level of wheat middlings (89W). Experiment 3. Diets with 43% WM, or 43% and 20% with 5% white grease added were evaluated with the same CSA control diet as in Experiment 2 to determine the benefits of increasing the ME content of these diets. Hen-day egg production results shown in Figure 1 (Experiment 3) reveal similar patterns of production throughout the 12 period cycle for all treatment hens. Feed consumption was highest for birds fed the 43W diet, and feed utilization was poor compared to that of other treatment groups (Table 2). These observations suggest the energy density of the 43W diet was low enough to

TABLE 2. Effects of wheat middling diets on measures of production

Experiment

Diet1

1

P+E P

M+ E M SEM 2

3

Feed consumption

Feed utilization

(%)

(g/hen/day)

(kg/12 eggs)

161 156 155 166 2

3.43ab 3.62 a 3.28 b c 3.14 c

ab

62.6 59.7 b 59.5 b 66.2 a .03 b

89W 43W 20W CSA SEM

48.8 65.7 a 63.7 a 70.1 a

43W

62.3 67.8 63.0 65.4

43WF 20WF CSA SEM 25W

4

Hen-day egg production

CSAM CSA CS SEM

.03

.04

59.4 67.2 64.9 68.2 .02

.07 a

135 126 b 112 c 118 c

4.03a 2.52 b 2.33 b 2.10 c

2

.06

126 a 122 b 110 d 117 c

2.74 2.28 2.29 2.29

1

.10

126 118 120 122 2

2.56 2.06 2.19 2.12 .14

a—d Experiment means in a column with no common superscripts are significantly different (P<.05). P = Pellet; M = mash; E = addition of the cellulase enzyme Trichoderma reesie; 89W = 89% wheat middlings (WM); 43W = 43% WM; 20W = 20% WM; CSA = corn, soybean meal, and alfalfa meal; 43WF = 43% WM plus 5% white grease; 20WF = 20% WM plus 5% white grease; 25W = 25% WM; CSAM = corn, soybean meal, alfalfa meal, and meat scraps; and CS = corn and soybean meal. 1

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were fed different amounts of WM in the diet. Those birds fed 89W had a production cycle similar to that of birds fed 91% WM in Experiment 1 (Figure 1, Experiment 2). Their average ME intake was only 70% of that (222 kcal ME/ hen per day) suggested by the NRC (1984) and 32% less than the ME intake (326 kcal ME/hen per day) of the CSA-fed birds. Colder weather and reduced hen house temperatures possibly caused 89W-fed hens to lay at a reduced rate (22.8%) and molt beginning in the 5th period of the cycle. December and January environmental temperatures (—11.8 and -9.6 C, respectively) were the coldest of the year and correspond with the loss of production observed in these periods. In eleven of twelve periods 89Wfed hens produced fewer eggs than hens fed the other treatment diets. In Periods 2, 7, and 9 the rate of lay was significantly lower than that of the 43W, 20W, or CSA-fed birds. Overall, henday production rates among the CSA, 20W, or 43W dietary treatments were not significantly different and only the 89W-fed hens produced

PATTERSON ET AL.

1334

Measures of Egg Quality The level of WM added to the diet did have a significant positive effect on mean HU in both Experiments 2 and 3 (Table 3). In Experiment 2, the 89W diet was responsible for the highest average HU (93.6); it ranked significantly higher than CSA, 20W, or 43W treatments. Lower

amounts of WM in the diet (43 W and 20W) also increased HU values; 43W and 20W eggs ranked significantly higher than CSA eggs. In all five periods the 89W-egg HU average was significantly greater than that of CSA eggs. A similar pattern was observed in Experiment 3, where 43W-fed hens produced eggs with higher HU than did birds fed CSA diets. Although the 43WF and 20WF diets were similar to those diets used in Experiment 2, except for the addition of white grease, feeding these diets did not significantly improve egg quality compared with that from CSA-fed birds. Again, in all five periods of HU evaluation, 43W-treatment eggs ranked higher than eggs from hens fed the CSA diet. Yolk color (YC) scores were also affected by the amount of WM in the diet (Table 3). The carotenoid content of these diets was diluted by the addition of WM and removal of corn; a significant progression toward higher YC scores was observed from the 89W to the CSA diets of Experiment 2. A similar pattern of YC scores was observed in Experiment 3, with CSA diets receiving higher YC (14.0) scores than the other WM-containing diets. The addition of WM to laying hen diets had no consistent effect on shell deformation scores. No differences were observed in combined egg weight means (Table 3) as a result of the various dietary treatments in either Experiment 2 or 3. The improvement observed in egg quality (HU) by feeding diets other than corn and soybean meal have been observed by other inves-

TABLE 3. Effects of wheat middling diets on measures of egg quality Experiment

2

3

Diet 1

Haugh unit score

Yolk color score2

Shell deformation

Egg weight

(1/1,000 mm) 89W 43W 20W CSA SEM

93.6 89.8 b 90.2 b 87.7 C 1.4

8.9 13.0 b 13.7^ 14.1 a .6

18.1 a 17.1 c 18^0 ab .5

(g) 55.9 56.2 55.7 55.2 .5

43W 43WF 20WF CSA SEM

85.5 a 84.2 b 84.2 b 83.6 b .7

12.6 b c 11.8 C 13.5ab 14.0 a 1.1

16.7 16.5 16.7 17.0 1.2

60.3 60.7 60.5 60.7 .5

a

C

i y yabC

Experiment means in a column with no common superscripts are significantly different (P<.05). 1

89W = 89% Wheat middlings (WM); 43W = 43% WM; 20W = 20% WM; CSA = corn, soybean meal, and alfalfa meal;43WF = 43% WM plus 5% white grease; 20WF = 20% WM plus 5% white grease. 2

Heiman Carver color wheel (Heiman and Carver, 1935).

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stimulate feed intake, yet intake was great enough to maintain production on par with that of birds fed higher energy diets. Experiment 4. In the last experiment there was no significant effect of dietary treatment on hen-day egg production (Figure 1, Experiment 4). Likewise, dietary treatments had no significant effect on feed consumption or feed utilization (Table 2). The split-plot design, with a repeated measures analysis on the hen-day egg production results, yields not only the significance of dietary treatment effects but also the time or period effect. In all experiments there was a highly significant period effect on hen-day egg production. This might be expected from any production curve. The cubic polynomial contrast for time probably best describes the data in each experiment. Also the time X diet interaction was significant beyond the .05 level in both Experiments 1 and 2, where there was a significant effect of treatment diets on percentage production. However, no significant interaction was observed in Experiments 3 and 4 where there was no significant diet treatment effect.

WHEAT MIDDLINGS AS AN ALTERNATE FEEDSTUFF

(Table 3). Despite HU differences, no definitive correlations between production and HU were observed in this experiment. Perhaps the best evaluation of the relationship between egg quality and production would be the correlation of HU among mature hens (so quality is not masked by youth) with the number of eggs laid for the entire cycle. Using this approach, HU from Periods 11 and 12 were found to be negatively correlated (P = .001) with the number of eggs laid (Experiment 2) as shown in Table 5. This suggests that within a mature flock, eggs of hens that lay well will have lower HU if quality differences exist. However, in Experiment 3, egg quality of mature hens (Period 11) was not correlated with the number of eggs produced (Table 5). In this period there were no quality differences as a result of the dietary treatments, and consequently the relationship did not hold. In summary, significant differences in HU and production observed in the present experiment did not bear out the high negative correlations observed by Harms and Douglas (1960) and Harms et al. (1962), but it is clear that among a large number of mature hens high levels of production adversely affect egg quality. Body Weight, Livability, and Reproductive Performance The energy contents of diets used in these experiments varied widely; these differences were generally responsible for the differences

TABLE 4. Within-period relationship of egg quality (HU = Haugh unit) and production level (PP = % hen-day egg production) (Experiment 2) Diet1

Variable

89W

Period 2

Period 8

Period 9

Period 11

Period 12

HU PP

93.65* 73.8 b

95.05* 44.4 C

98.75* 30.7 b

91.45* 60.4

89.25* 26.0

43W

HU PP

92.25 a b 89.6*

88.60 b 63.5ab

89.70 c 68.8*

88.25 b 44.3

90.25* 35.4

20W

HU PP

91.30 b 89.9*

89.25 b 52.7bc

93.00 b 53.1*

88.25 b 49.8

88.95* 33.4

CSA

HU PP

90.90 b 89.2*

88.80 b 68.5*

89.25 c 60.6*

85.05 c 61.8

84.65 b 46.5

Correlation coefficient: Significance level: No. of eggs:

-.10 .03 490

.001 .99 308

-.21 .0004 279

-.08 .22 218

-.33 .0001 132

Means within each column and variable with no common superscripts are significantly different (P<.05). 1

89W = 89% Wheat middlings (WM); 43W = 43% WM; 20W = 20% WM; CSA = corn, soybean meal, and alfalfa meal.

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tigators feeding brewers grains (Jensen et al., 1978; White et al., 1979), distillers grains (Waldroup and Hazen, 1978; Jensen et al., 1978; Jensen and Maurice, 1978), barley, oats, and WM (Mueller, 1956; Harms and Douglas, 1960; Harms et al., 1962). Trace minerals such as Cr and V, and bird strain are also believed to be factors involved in egg quality differences. Many workers suggest that the level of egg production is an underlying factor in the differences in egg quality (Harms and Douglas, 1960; Harms et al, 1962; White et al., 1979), in that dietary treatments that adversely affect production tend to raise HU. However, others have induced significant differences in egg quality without corresponding differences in production (Mueller, 1956;Skala, 1969; Sell etal., 1982). In Experiment 2, correlations between egg production and HU were significant beyond the .05 level for three periods (Table 4), suggesting an inverse relationship (as production increases, HU decrease). However, despite significance, the negative correlation coefficients (-.10, -.21 and -.33) were not as great as those observed by Harms and Douglas (1960) (-.62) and Harms et al. (-.81; 1962). Correlations reported by Harms and Douglas (1960) and Harms et al. (1962) were made on overall hen production for a year with a single (36 wk of age) measure of egg quality. During Experiment 3, a significant diet effect on HU was observed (Table 3) but there was no difference in overall hen-day egg production

1335

PATTERSON ET AL.

1336

TABLE 5. Relationship of mature hen egg quality (Haugh unit) to laying ability (number of eggs produced in 12 periods)1 Variable

Experiment 2

Experiment 3

Haugh unit Laying ability Correlation coefficient Significance level n

87.73 210 -.33 .0001 173

80.11 244 -.11 .22 132

1

Haugh unit measures for Experiment 2 were made in Periods 11 and 12 and in Period 11 for Experiment 3.

TABLE 6. Initial and final body weights and hen livability rates (Experiment 1) Diet 1

20-wk BW

P+E P M+E M SEM

1,370 1,350 1,360 1,360 12

66-wk BW

Livability

(%)

(g) l,930 a 1,915* l,820 b l,885 a 14

67.5 61.2 87.5 91.2

ab ' Means within each column with no common superscripts are significantly different (P<.05). ' P = Pellet; M = mash; E = addition of cellulase enzyme Trichoderma reesie.

the majority of the cases could not be determined. However, the digestive tract was blocked at the ileum in 12.3% of the cases and leukosis and prolapse accounted for 9.6% of the deaths. Season of the year may be related to the death losses, with the majority (86.3%) occurring from November to February. January and February were unseasonably cold this particular year, with temperatures of-13.3 C and -7.2 C, respectively, and losses during these months were coincident with the lowest feed intakes and egg production rates of the entire cycle. Of hens that died, the majority (64.4%) was still laying within 1 week prior to their deaths. Livability was also low (73.8%) in Experiment 2 hens fed the 89W diet. Again, the specific cause of death could not be determined in a majority of the cases. However, unseasonably hot weather in July (23.9 C) may be responsible for the 40.9% of the losses that occurred in this month. Concurrent with the rise in temperature was a drop in production from 60.4% in June to 26% in July, and a decrease in feed consumption. Of birds that died, the majority was still laying within 1 week prior to their deaths, suggesting that heat stress rather than chronic disease may be the cause. Mortality in the other months of the year was evenly distributed and all other treatment groups in this experiment had normal livability rates. There were no trends in livability in either Experiments 3 or 4 that would suggest dietary treatment differences. In addition, mortality rates averaged only 7.5% in each experiment. Reproductive performance was also evaluated in Experiments 2, 3, and 4. In Experiment 2 hatchability was maintained at greater than 90%. During Experiments 3 and 4 fertility, hatchability, and percentage hatch of hens fed WM diets compared favorably with results from hens fed the CSA control diets. When evaluated for growth, livability and nutritional deficiency

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in egg production and feed utilization observed. The greatest difference in ME content was found between the 89W (1,640 kcal/kg) diet and the CSA diet (2,780 kcal/kg) used in Experiment 2. These diets, or similar diets used in Experiments 3 and 4, did not, however, produce significant differences in final body weights of the birds. Only in Experiment 1 were there significant differences in final body weights of birds. Hens fed the M + E diet were significantly lighter than any of the other birds fed the 91%WM basal diet (Table 6). Average body weights during the trial were significantly (P<.05) higher among birds fed pelleted diets than among birds fed mash diets: 1,640 g vs. 1,610 g, respectively. Addition of T. reesie preparation to diets had no effect on hen body weight. Livability was adversely affected in Experiment 1 by feeding 91%-WM diets in pelleted form (Table 6). Hens fed either the M or M + E diets had mortality rates of about 10%, which is considered normal, but birds fed the P + E and P diets experienced mortality rates of 32.5% and 38.8%, respectively. The cause of death in

WHEAT MIDDLINGS AS AN ALTERNATE FEEDSTUFF

REFERENCES Bayley, H. S., J. D. Summers, and S. J. Slinger, 1968a. The influence of steam pelleting conditions on the nutritional value of chick diets. Poultry Sci. 47:931939. Bayley, H. S., J. D. Summers, and S. J. Slinger, 1968b. Effect of heat treatment on the metabolizable energy value of wheat germ meal and other wheat milling by-products. Cereal Chem. 45:557-563. Bearse, G. E., 1941. Mill ran in the breeders' mash. Northwestern Miller 205:31. Biely, J., and C. Goudie, 1971. Growth of chicks and hatchability of eggs of three generations of White Leghorn pullets fed "wheat" as the sole protein source. Feedstuffs 43:32. Cave, N.A.G., S. J. Slinger, J. D. Summers, and G. C. Ashton, 1965. The nutritional value of wheat milling by-products for the growing chick. Cereal Chem. 42:523-533. Harms, R. H., and C. R. Douglas, 1960. Relationship of rate of egg production as affected by feed to Haugh

units of eggs. Poultry Sci. 39:75-76. Harms, R. H., W. B. Lester, and P. W. Waldroup, 1962. Further studies on the relationship of egg production rate as affected by feed to Haugh units of eggs. Poultry Sci. 41:578-580. Haugh, R. R., 1937. The Haugh unit for measuring egg quality. U.S. Egg and Poult. Mag. 43(9):552-555, 572-573. Heiman, V., and J. S. Carver, 1935. The yolk color index. U.S. Egg and Poult. Mag. 41(8):40-42. Jensen, L. S., C. H. Chang, and S. P. Wilson, 1978. Interior egg quality: Improvement by distillers feeds and trace elements. Poultry Sci. 57:648-654. Jensen, L. S., and D. V. Maurice, 1978. An assessment of nutritional factors affecting the condition of egg albumin. Proc. XVI World's Poult. Congr. IV-EF:566570. Moran, Jr., E. T., J. D. Summers, and W. F. Pepper, 1970. Nutritional evaluation of selected milling fractions from wheats of different type and geographical area of production: First three limiting essential amino acids for the chick and performance under dietary conditions calculated adequate. Poultry Sci. 49:371-387. Mueller, W. J., 1956. The influence of energy source, energy-fiber concentration and protein source of the diet on certain egg quality characteristics. Poultry Sci. 35:1074-1078. National Research Council, 1984. Nutrient Requirements of Poultry. Nutrient Requirements of Domestic Animals. 8th revised ed. Natl. Acad. Sci., Washington, DC. Preston, R. L., 1985. Typical composition of feeds for cattle and sheep (1985-86). Feedstuffs 57:15-18, 35. SAS, 1982. SAS User's Guide. SASInst. Inc.,Cary,NC. Saunders, R. M., H. G. Walker, Jr., and G. O. Kohler, 1969. Aleurone cells and the digestibility of wheat mill feeds. Poultry Sci. 48:1497-1503. Sell, J. L., J. A. Arthur, and I. L. Williams, 1982. Adverse effect of dietary vanadium, contributed by dicalcium phosphate, on albumin quality. Poultry Sci. 61:21122116. Skala, J. H., 1969. Studies of variation in initial quality of chicken eggs. Poultry Sci. 48:164-171. Summers, J. D., S. J. Slinger, W. F. Pepper, and E. T. Moran, Jr., 1968. Biological evaluation of selected wheat fractions from nine different wheat samples for energy and protein quality. Poultry Sci. 47:17531760. Waldroup, P. W., and K. R. Hazen, 1978. Evaluation of DSLC and various feed additives as potential sources of a Haugh unit improvement factor. Poultry Sci. 57:1169. (Abstr.) White, W. B., 1982. Enzymatic improvement of barley for chicks and the use of high-fiber feeds for laying hens. Ph.D. Diss. Univ. of Wis., Madison, WI. White, W. B., M. L. Sunde, H. R. Bird, W. C. Burger, and N. Prentice, 1979. Brewers' dried grains in laying mashes. Feedstuffs 51:27-28.

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symptoms, no differences were found among rates in chicks raised from any of the treatment hens. Biely and Goudie (1971) also observed high hatchability and satisfactory growth using chicks hatched from three consecutive generations of pullets fed wheat as the sole protein source. In summary, the feeding of high levels of WM to laying hens (91% WM in Experiment 1; 89W in Experiment 2) can result in loss of production if normal house temperature and feed intake are not maintained. However, when diets contained as much as 43%, 25%, or 20% WM, production was maintained as well as that of hens fed CSA control diets in Experiments 2, 3, and 4. Pelleting of high WM diets (91% WM, Experiment 1) resulted in poor feed utilization and elevated body weights, relative to those of hens fed mash diets. Livability appears to be adversely affected by the pelleted diets used in Experiment 1 and the crumbled 89W diet in Experiment 2, when birds are exposed to extremes in environmental temperatures. Lastly, Haugh units were elevated and yolk color was reduced when hens were fed the 89 and 43% WM diets, relative to scores of eggs from hens fed the CSA control (Experiment 2 and 3).

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