Apparent ileal amino acid digestibility of reduced-oil distillers dried grains with solubles fed to broilers from 23 to 31 days of age.

An experiment was conducted using male Ross×Ross 708 broiler chicks to determine the effect of oil extraction from corn distillers dried grains with solubles on apparent ileal amino acid digestibility from 23 to 31 d of age. On an as-fed basis, ether extract concentrations were determined as 5.4% (L-distillers dried grains with solubles), 7.9% (M-distillers dried grains with solubles), and 10.5% (H-distillers dried grains with solubles) for the 3 experimental distillers dried grains with solubles sources. Prior to experimentation, each sample (H-distillers dried grains with solubles (control), M-distillers dried grains with solubles and L-distillers dried grains with solubles) was analyzed on an as-fed basis for crude protein (29.2, 27.6, and 27.9%), starch (4.4, 5.2, and 6.1%), neutral detergent fiber (29.5, 33.2, and 29.9%), and total dietary fiber (31.4, 36.6, and 33.6 %). Four hundred and thirty-two male chicks (12 birds per cage; 0.04 m2 per bird) were randomly assigned to 36 battery grower cages. Broilers were fed one of 3 semi-purified diets, which were comprised of 76% L-distillers dried grains with solubles, M- distillers dried grains with solubles, or H-distillers dried grains with solubles as the sole amino acid source from 23 to 31 d of age. Apparent ileal amino acid digestibility coefficients were negatively affected (P<0.05) by oil extraction for Met (0.722, 0.788, and 0.791), Lys (0.504, 0.510, and 0.552), Thr (0.563, 0.566, and 0.612), Trp (0.708, 0.733, and 0.767), and Arg (0.762, 0.776, and 0.799) for L-distillers dried grains with solubles, M-distillers dried grains with solubles, and H-distillers dried grains with solubles, respectively. Conversely, no differences in apparent amino acid coefficients were reported for Ile, Leu, and Val. These results indicated that L-distillers dried grains with solubles had lower apparent amino acid digestibility coefficients for Met, Lys, Thr, Trp, and Arg compared with H-distillers dried grains with solubles.

Feed enzyme supplementation does not ameliorate Foot Pad Dermatitis in broiler chickens fed on a corn-soyabean diet.

1. Foot Pad Dermatitis (FPD) can be a serious health, quality and welfare problem in poultry production, with a significant affect on the economics of production. The physico-chemical properties of (NSP) have been correlated with increases in excreta viscosity and adherence, and hence FPD in broiler chickens. 2. Two broiler experiments were conducted to evaluate the effects of different dietary non-starch polisaccharide (NSP) applications to corn-soyabean based diets in replicated floor pens. In addition to live performance, the incidence and severity of FPD was scored and, in experiment 2, intestinal viscosity and ammonia volatilization were measured. 3. Live performance did not vary with the different treatments in either experiment and the incidence and severity of FPD, and ammionia volatisation in experiment 2, were unaffected. However, birds reared on enzyme supplemented diets had lower (P < 0·001) intestinal viscosity levels in experiment 1. 4. In this study with corn-soyabean meal based diets, dietary enzyme supplementation had no affect on the incidence and severity of FPD. The lack of an association between the excreta viscosity and FPD is attributed to the multifactorial etiology of this condition.

Effect of dietary glutamine supplementation on Salmonella colonization in the ceca of young broiler chicks.

Live poultry is an important vehicle for transmitting Salmonella Typhimurium to humans that have salmonellosis. It is therefore imperative to reduce Salmonella Typhimurium levels in the gastrointestinal tract of live chickens. Glutamine is an established immunonutrient that is capable of alleviating disease conditions in humans and rats. Thus, 2 experiments that used Ross broiler chicks were conducted to evaluate the effect of glutamine supplementation at 1% level of the diet on cecal Salmonella Typhimurium levels in young broiler chicks. Experiment 1 consisted of i) treatment 1 (control, CN), in which chicks were given an unmedicated corn-soybean meal basal starter diet without glutamine supplementation or Salmonella Typhimurium challenge; ii) treatment 2 (CST), in which chicks were given the same diet as CN but challenged with 3.6 x 10(6) cfu Salmonella Typhimurium/mL at 3 d of age; and iii) treatment 3 (GST), in which chicks were given the unmedicated corn-soybean meal basal starter diet supplemented with glutamine at 1% level, and challenged with 3.6 x 10(6) cfu at 3 d of age. Experiment 2 used similar treatments (CN, CST, and GST), except that chicks in CST and GST were challenged with 7.4 x 10(7) cfu Salmonella Typhimurium/mL, and a fourth treatment was added. The fourth treatment consisted of chicks that were not challenged with Salmonella Typhimurium but given the same diet as in GST. Duration of each experiment was 14 d. Growth performance of chicks was monitored weekly, and cecal Salmonella Typhimurium concentration was microbiologically enumerated on d 4, 10, or 11 postchallenge. Results showed that glutamine supplementation improved BW and BW gain in experiment 2 (P < 0.05) but did not reduce cecal Salmonella Typhimurium levels in either experiment (P > 0.05). The optimum supplemental level of glutamine that will enhance intestinal resistance to Salmonella Typhimurium colonization should be determined.

Influence of long-bright and increasing-dim photoperiods on live and processing performance of two broiler strains.

The influence of long-bright and increasing-dim photoperiods on live and processing performance was investigated in 2 broiler strains. Fifty males of moderate (M) and high (H) yield strains were placed by strain in 2 pens in each of 12 rooms. Six rooms were provided a long-bright photoperiod (LB treatment) of 23L:1D with 2 footcandles of intensity. The other 6 rooms were provided an increasing-dim photoperiod (ID treatment) of 20L:4D from 1 to 10 d, 12L:12D from 10 to 21 d, 15L:9D from 21 to 28 d, 18L:6D from 28 to 35 d, and 20L:4D from 35 to 54 d, with 0.1 foot-candle throughout. Relative to LB, the ID treatment had lower BW from 7 to 28 d, feed consumption from 7 to 35 d, and feed conversion from 7 to 42 d; however, these variables did not differ between treatments at 54 d. The M strain had consistently greater BW and feed consumption than the H strain. However, M strain feed conversion was only greater from 7 to 35 d. Mortality was unaffected by treatment or strain. Total breast weights and yields were 42 g or 5.1% greater, respectively, in the LB than the ID treatment. Fillet weights and yields, and tender yields, were greater in the LB than ID treatment. Leg weights and yields, and wing yields, were greater in the ID than LB treatment. Total breast weights of M and H strains were similar; however, yield was 3.3% greater in the H than M strain. Fillet yields were greater in the H than M strain. Wing and leg weights and yields were greater in the M than H strain. There was an interaction effect on fat pad weights and yields, which were greater in H strain subjected to ID treatment than other strain and treatment combinations. These results indicate that increasing photoperiods and dim intensities, which often improve broiler live performance, may have a greater negative effect on breast meat production than differences in strains.

Response of coccidiostat- versus vaccination-protected broilers to gelatin inclusion in high and low crude protein diets.

Experimentation examined if Gly and Ser (Gly + Ser) and Pro from gelatin inclusion in low and high CP feeds would relieve impaired performance of broilers after vaccination for coccidiosis. Broilers in floor pens were fed 20-18-16% or 23-20-18% CP corn-soybean meal regimens from 0 to 8 wk of age such that 1 or more of the most limiting essential amino acid levels were similar across treatments and considered adequate respective of age. Gelatin was included in diets at 2%, which contributed Gly + Ser and Pro levels comparable to using 5% meat meal. Half of the chicks were spray-vaccinated with live oocysts before placement and received nonmedicated feed, whereas the other half received coccidiostat-medicated (salinomycin) feed to 6 wk of age. Vaccination adversely affected live performance in the first 3 wk, which could not be fully compensated to the level of birds receiving coccidiostat by the end of experimentation. Inclusion of gelatin mitigated vaccination response through the first 3 wk, while improving overall live performance of birds fed low CP diets. Gelatin had no effect on carcass composition, but the low CP regimen increased abdominal fat and reduced carcass and breast meat relative to high CP feeds. Vaccination also reduced overall carcass weight; however, part yields were not affected. Males were generally more sensitive to treatments than females. The conditionally essential amino acids Gly + Ser and Pro may be important factors in recovery from live anticoccidial vaccines.

Effect of light intensity on live performance and processing characteristics of broilers.

This study investigated the effects of different light intensities provided via an increasing photoperiod program on broiler live performance and processing characteristics. A total of 1,080 male broilers were evenly distributed in 12 rooms. Six rooms were subjected to intensities of either 15 footcandles (FC) from 1 to 51 d (Bright), or 0.5 FC from 1 to 9 d and 0.1 FC from 9 to 51 d (Dim). Both intensity treatments were provided in an increasing photoperiod program (23L:1D, 1 to 9 d; 12L:12D, 9 to 16 d; 14L:10D, 16 to 23 d; 17L:7D, 23 to 30 d; 20L:4D, 30 to 37 d; and 23L:1D, 37 to 51 d). Feed consumption and BW were determined, and feed conversions were calculated approximately weekly. Mortalities were necropsied and recorded daily. At 51 d, 30 birds from each room were processed and cut up to determine weights and yields. Beginning at 23 and 30 d, respectively, BW and feed consumption were greater in the Dim treatment. At 51 d, Dim treatment BW was 4.7% greater and feed consumption was 3.9% greater. Feed conversion, metabolic and total mortality, and BW uniformity were not influenced by light intensity. Weights of lean carcass, total breast, fillets, tenders, and legs were from 4.9 to 6.2% greater in the Dim treatment, which was proportional to the BW difference and resulted in similar yields of these parts. However, wings were 9.9% heavier in the Dim treatment, which resulted in greater wing yield. Equal fat pad weights resulted in reduced fat pad yield in the Dim treatment. These results indicate that BW, feed consumption, and most parts weights were increased proportionally by providing 0.1 vs. 15 FC of light intensity via an increasing photoperiod program, and that only the yields of minor parts were affected by intensity.

Effect of light intensity and photoperiod on live performance, heterophil-to-lymphocyte ratio, and processing yields of broilers.

This study investigated effects of light intensity and photoperiod on live and processing performance and physiological stress of broilers. One hundred broilers were housed in each of 12 rooms, provided 23L:1D with 3 footcandles (FC) of intensity to 8 d, and then subjected to the following treatments in a 2 x 2 factorial arrangement: either 1 FC (1FC) or 0.1 FC (0.1FC) from 8 to 49 d and either 23L:1D from 8 to 49 d (23L) or 18L:6D from 8 to 43 d followed by 23L:1D from 43 to 49 d (18L). At 40 d, blood samples were drawn and heterophil:lymphocyte ratios determined. At 49 d, 16 birds from each room were processed to determine weights and yields. There were interaction effects on BW from 29 to 49 d. At 29 d, BW was reduced by either 18L or 0.1FC treatments. At 43 d, BW was greatest in 1FC-23L, reduced in 1FC-18L and 0.1FC-23L, and intermediate in the 0.1FC-18L treatment. At 49 d, BW of 1FC-23L and 0.1FC-18L were similar and greater than those of 1FC-18L and 0.1FC-23L treatments. Feed consumption was reduced by 18L treatment from 15 to 29 d and the 0.1FC treatment at 15 d. Feed conversion and mortality were not affected by treatments. The 0.1FC treatment decreased uniformity at 15 d. Heterophil:lymphocyte ratios averaged about 0.45 and were not affected by treatments. Carcass yield and tender weight were reduced by the 0.1FC treatment, whereas whole breast yield was reduced by the 18L treatment. There were interaction effects on whole breast weight and fillet weight and yield, which were reduced by either the 18L or 0.1FC treatments. These results indicate that although the combination of 18L:6D and 0.1FC may result in broiler live performance comparable to that achieved with 23L:1D and 1FC, and no combination of the photoperiods and intensities tested caused physiological stress, breast meat is generally reduced by either 18L:6D or 0.1FC.

A longitudinal study of Salmonella and Campylobacter jejuni isolates from day of hatch through processing by automated ribotyping.

Comparisons of bacterial populations over long periods of time allow researchers to identify clonal populations, perhaps those responsible for contamination of farms or humans. Salmonella and Campylobacter can cause human illness, and our objective was to use a library typing system to track strains that persist in the poultry house and through the processing plant. Two farms, over four consecutive flocks, were studied. Multiple samples were taken of the poultry house environment, feed mill, transport crates, and carcasses in the processing plant. Sample collection on the farm took place on chick placement day, midgrowout, and the day of harvest. This study found that 80.3% of isolates belonged to a single strain of Salmonella Kentucky that persisted in several environmental samples for all flocks at both farms, from chick placement day to the final product at the plant. Surgical shoe covers produced most isolates (n = 26), and processing day yielded the highest recovery (n = 68). Additional serotypes were recovered, but the Salmonella Kentucky-positive eggshells and chick mortality appeared to be the source of the organism for both farms. All Campylobacter isolates recovered were identified as C. jejuni. Most Campylobacter isolates (90.1%) belonged to one of three core strains. C. jejuni was not recovered on chick placement day. Cecal droppings yielded all nine strains. Most isolates (98.2%) were from one farm. Cluster analysis grouped C. jejuni and Salmonella isolates into four and six distinct clusters, respectively, on the basis of a similarity level of 80%.

Acute pulmonary edema following intravenous fluorescein angiography.

A 64-year-old white man with no history of cardiac or bronchopulmonary disease developed acute pulmonary edema shortly after undergoing diagnostic intravenous fluorescein angiography. The patient responded quickly to a course of oxygen, positive pressure breathing, diuretics, and sedation.

The effect of vitamin E on cellulitis in broiler chickens experiencing scratches in a challenge model.

Two experiments are described; each experiment contained five treatments with each treatment consisting of a specific diet and vitamin E at 8.82 mg, 41.89 mg, 74.96 mg, 108.03 mg, or 141.10 mg vitamin E per kilogram of feed. Birds were raised with continuous feed containing the various levels of vitamin E available throughout the experiment. At 4 wk of age, the birds were scratched on the breast and placed onto avian cellulitis Escherichia coli-seeded litter. One week later, the birds were euthanatized and lesion presence was noted. There appeared to be a positive correlation between vitamin E and the inhibition of cellulitis formation when the birds were fed a diet containing 74.96 mg vitamin E/kg feed. Conflicting results were seen in the two experiments when the birds were fed 41.89 and 108.03 mg vitamin E/kg feed. Both experiments had a high incidence of cellulitis in birds whose diets consisted of 141.10 mg vitamin E/kg feed.

Evaluation of a rendered poultry mortality-soybean meal product as a supplemental protein source for pig diets.

Dehydrated/rendered broiler mortality-soybean meal products (DPS) were evaluated in two trials as high-protein feedstuffs for pig diets. Broiler mortalities, collected and frozen on-farm and transported to a central facility, were minced, blended with soybean meal, and dried with a final product temperature of 120 to 130 degrees C. The final DPS products used contained approximately 30 and 45% (DM basis) dried broiler mortality for the first and second trials, respectively (DPS1 and DPS2). The first trial involved 50 young, growing pigs (9 to 26 kg) and the second, 72 growing and finishing pigs (27 to 111 kg). The trials compared corn-based diets containing either soybean meal (SBM; 48%) or DPS products as the supplemental protein source. The DPS products averaged 50% CP and 2.9% total lysine; crude fat content of DPS used in the first trial was 8%, and for the second, 14.6% (as-fed basis). The ADG of pigs fed the DPS diets in either trial was similar to that of pigs fed the SBM control diets. In the second trial, pigs fed DPS2 had an overall average G:F ratio that was 9% better (P < 0.01) than that of pigs fed the SBM control diets. Carcass characteristics and pork quality from pigs of the growing-finishing trial were not affected by dietary treatment. Subjective carcass fat firmness scores indicated slightly softer fat (P < 0.05) from pigs fed DPS2. The mincing, blending with SBM, and dehydration of frozen stored on-farm broiler mortalities produced a safe and nutritious protein feedstuff for pigs, while also offering a viable disposal option.

Meningococcal endophthalmitis without meningitis.

Meningococcal endophthalmitis is usually diagnosed by the isolation of organisms from specimens of cerebrospinal fluid or blood, rarely from aspirates of aqueous or vitreous. In the case reported in this paper the organisms were isolated from both the aqueous and the vitreous but not from any extraocular specimens.

A new rationale for the management of large angle esotropia.

It is not only possible but safe to exceed the traditional 5 mm maximum recession of each medial rectus muscle to correct large angle esotropia. It is possible to grade the amount of recession to the preoperative deviation, similar to that which is done for esotropia less than 35 prism diopters. The results of this series indicate that alignment to within 10 prism diopters with one procedure is more likely by large recessions of the medial rectus than by other approaches. If a reoperation is necessary, there still remain two other untouched horizontal muscles on which to operate.

Effects of dietary magnesium excess in White Leghorn hens.

The effects of excess dietary magnesium on White Leghorn laying hens were investigated in two experiments and a third experiment looked at the effect of dietary phosphorus on excess magnesium in the diet. In Experiment 1, magnesium levels of 0.15, 0.8, and 1.2% were fed in a diet containing 2.5% calcium to hens 30 wk of age for 5 wk. A control diet with 3.5% calcium and 0.15% magnesium was also fed. In Experiment 2, hens 65 wk of age fed 3.5% calcium were fed dietary magnesium levels of 0.15, 0.36, 0.53, 0.76, and 0.91% for 4 wk. In these two experiments, excess magnesium reduced egg production, decreased feed consumption, decreased body weight, decreased percentage eggshell, reduced plasma calcium, and increased plasma magnesium and tibia magnesium but changes seen in tibia weight, percentage ash, and tibia calcium and phosphorus were variable. More changes from feeding excess magnesium were seen in the young, high producing hens in Experiment 1. In Experiment 3, hens 50 wk of age were fed a marginal calcium level (2.5%) with an excess of magnesium (0.8%) and a control level of available phosphorus (0.45%) and this was compared to a low (0.25%) and a high level (0.9%) of available phosphorus for a 4-wk experimental period. At the end of the experimental period, hens fed low phosphorus had lower egg production and lower feed consumption than the hens fed higher levels of phosphorus. Body weight was lower in the hens fed the two lower levels of phosphorus. Percentage eggshell was lower than the controls when fed low phosphorus and higher when fed high phosphorus. These results suggest that high phosphorus diets are better than low phosphorus diets when excess magnesium is fed to laying hens. Further study is needed to investigate the role of phosphorus when excess magnesium is fed.

The effects of halofuginone and salinomycin, alone and in combination, on live performance and skin characteristics of female broilers: influence of a high-proline diet supplemented with ascorbic acid and zinc.

Live performance and carcass quality of female broilers were evaluated under four coccidiostat programs (CP) and two feed treatments. The CP consisted of halofuginone (H) and salinomycin (S), fed either continuously (HH and SS) or in rotational programs (HS and SH), during the starter (1 to 21 d) and grower (22 to 35 d) periods, respectively. All groups received an unmedicated withdrawal feed from 36 to 42 d. Feed treatments consisted of a control and a fortified diet high in proline and supplemented with additional ascorbic acid and zinc (50 birds per pen; 4 pens per feed; 8 pens per CP). In addition to live performance and skin puncture strength, carcass quality attributes following processing (at 43 d of age) were assessed. No CP by feed interactions were detected for any of the variables measured. The CP treatments did not differ for live performance. Birds on fortified feed were heavier at 21 d (P < .001) and had an improved feed conversion at 42 d (P < .05). Skin puncture strength was significantly reduced for the birds fed H, either in continuous (HH) or rotational programs (HS and SH). Skin sores-scratches and tears were lowest for the SS and SH groups. The HH treatment resulted in fewer grade A carcasses (P < .001). Halofuginone, when fed continuously or in the starter feed, affected carcass quality of broilers. Higher dietary proline or supplementation with ascorbic acid and zinc did not appear to alleviate the effects of halofuginone on skin quality.

Breast muscle development in commercial broiler chickens.

Genetic and gender-related variations in breast muscle yield of broiler chickens may be attributed to differences in number and size of muscle cells (myofibers). In this study, male and female broilers from eight commercial strain crosses (SC) were compared for body and breast muscle weight with adjustment of the Gompertz function. Additionally, breast fillet dimensions (length, width, and depth) and myofiber density (myofiber number/area; MFD) were assessed. Live weight and breast muscle development was determined to 56 d of age at weekly intervals. MFD was assessed at 8 d of age. As expected, SC differed in BW, breast weight and yield, and breast fillet dimensions and had variations in growth curves. Maximal growth rate for breast weight was reached approximately 4 d after that of BW. Males and females showed different growth curves, with males having slower growth rate maturity parameter and reaching the maximal growth rate later than females for BW and breast weight. Breast depth was the breast measure with highest positive correlation to breast yield. SC differences could not be explained by MFD, but males had higher MFD density than females. The possible relationship of the MFD observations to total myofiber number is discussed.

The effects of halofuginone and salinomycin, alone and in combination, on live performance and skin characteristics of broilers.

Live performance and skin characteristics of male and female broilers were evaluated under four coccidiostat feed additive programs. Treatments consisted of halofuginone (H) and salinomycin (S), fed either continuously (HH and SS) or in rotational programs (HS and SH) during the starter (1 to 21 d) and grower (22 to 35 d) periods, respectively. An unmedicated withdrawal feed was provided from 36 to 42 d of age. Body weights, feed efficiency, and mortality (by pen) were determined, in addition to skin puncture strength measurements taken at Days 21, 35, and 42 on five birds per pen. At 43 d of age, all birds were processed and individually graded for skin defects. There were no treatment by sex interactions for any variable measured. Male body weights, feed efficiency, and total mortality exceeded those of females (P < .05). Skin puncture strength was reduced at 21 d in the HH and HS groups, at 35 d in the HH and SH groups, and at 42 d in the HH, HS, and SH groups. Thigh sores and scratches were higher for the HH group (P < .05), and thigh skin tears were higher for the HH and HS groups (P < .01). Males had more swollen hock joints and breast blisters than females (P < .001). Females had more thigh skin tears (P < .01) and broken wings (P < .001) than males. Results of the present study demonstrated that halofuginone affected skin strength of broilers, especially when used continuously or only in the starter feed (1 to 21 d).

Peanut hulls as a litter source for broiler breeder replacement pullets.

Broiler breeder pullets were reared on either peanut hulls or pine shavings to determine effects of litter type on growth performance and litter characteristics. Pullets were reared to 20 wk of age in rooms initially bedded with 8 cm of clean shavings or hulls. Heating and ventilation were standardized in all rooms. Restricted skip-a-day feeding was used to attain recommended growth curves. Water was continuously provided for ad libitum consumption. Litter and environmental variables were measured throughout rearing and 2 wk after pullets were removed from the litter materials. Feed consumption, BW, mortality, and uniformity at 20 wk were not affected by litter type; however, gizzard weights were decreased in pullets reared on hulls. Litter bulk density increased with use and was greater for shavings through 11 wk, but not thereafter. Particle size decreased with use in both litter types. Through 11 wk, there were more particles in the > 4 mm range and less in the < 1.7 mm range with hulls. Litter moisture increased with use but was not affected by litter type. Litter pH was greater in unused shavings, but during and after use was generally greater in hulls. With both litter types, litter and environmental ammonia levels increased to 11 wk then decreased; however, this effect was more pronounced for hulls. Bacteria populations were not affected by litter type; however, greater fungal populations were observed in shavings at 7 and 15 wk. Aflatoxins were detected in unused hulls but not shavings. Because aflatoxin levels decreased during use and Aspergillus flavus and Aspergillus parasiticus populations were not detected in samples collected during use, aflatoxins observed were presumed to have been formed prior to use. Peanut hulls performed similarly to pine shavings as a litter source for breeder pullets; however, the specific influence of the aflatoxins contained in this litter source on bird performance deserves further study.

Localization of chicken parathyroid glands through vital staining.

Five, fat-soluble dyes and one, metachromatic tissue dye were administered to White Leghorn hens and broilers to determine how these compounds would color parathyroid tissue for subsequent gland localization. Sudan black, sudan red, canthaxanthin, oil red O, beta-apo-8'-carotenal, and toluidine blue O were administered orally in gelatin capsules once a day for 1, 2, or 3 days before slaughter. The dyes were administered at approximately 100 mg/dose. The carotenoid pigments were given at 200 mg/dose. Two administrations were required to develop sufficient visible staining. All dyes except the toluidine blue O were visibly deposited in the parathyroid glands. Sudan black resulted in the greatest contrast with surrounding adipose tissue. Male broilers 3 wk of age that were given one dose of sudan black showed gland definition comparable to that seen in the hens after two doses. Male broilers 5 wk of age showed less gland definition when given sudan black or sudan red for 1 or 2 days. A histological examination indicated that the fat-soluble dyes were located extracellularly. These results indicate that sudan black can be used to visually identify the parathyroid glands of chickens.

Threshold retinopathy of prematurity. Transition from cryopexy to laser treatment.

PURPOSE: The authors studied the effectiveness of laserpexy versus cryopexy for treatment of acute retinopathy of prematurity. METHODS: Seventy-six eyes in 41 patients were treated for acute retinopathy of prematurity from January 1991 to April 1994. RESULTS: Fifty-six eyes in 30 patients had zone 2 disease. Of these 30 patients, 11 received laser treatment and 20 received cryopexy treatment; there was at least one anatomically successful eye in each patient. Twenty eyes in ten patients had zone 1 disease. Seven patients had bilateral laser treatment. Three patients had bilateral cryopexy. In seven eyes with zone 1 disease, five were treated successfully with laser. None of the three eyes with zone 1 disease treated with cryopexy were successful. CONCLUSION: Laserpexy and cryopexy are of equal efficacy in treating zone 2 disease. There is a tendency that suggests that laserpexy is more effective than cryopexy in treating zone 1 disease. Diode and argon lasers are of equal efficacy in treating zone 1 disease.