The interrelationship between crude protein and exogenous porcine somatotropin on growth, feed and carcass measurements of pigs.

In three experiments the interrelationship between dietary CP and recombinant porcine somatotropin (rpSt, i.m. daily) on ADG, feed efficiency (F/G) and carcass traits was examined in crossbred Yorkshire gilts and barrows given ad libitum access to their diets during the finishing period (55 to 110 kg BW). Pigs, blocked by BW and gender, were assigned (four/pen) within block. In Exp. 1, 140 pigs were assigned two/gender per pen to each of five pens/block and received a diet of either 12%, 18% or 24% CP (n = 2, 1 and 2 pens/block, respectively). Pigs received rpSt, either 0 or 120 micrograms/kg BW (12% and 24% CP groups) or 60 micrograms/kg BW (18% CP group). When CP was 12%, rpSt decreased ADG and increased F/G (P less than .05), whereas when CP was 18% or 24%, rpSt increased ADG and lowered F/G (P less than .05). Backfat thickness was reduced (P less than .05) by rpSt regardless of CP. In Exp. 2, 120 pigs were assigned two/gender per pen to each of five pens/block and received a diet of 24% CP. Either 0, 15, 30, 60 or 120 micrograms of rpSt/kg BW was administered to each pig. All doses of rpSt increased ADG, lowered F/G and decreased backfat thickness compared with measurements for control pigs (P less than .05). In Exp. 3, 140 pigs were assigned two/gender per pen to each of seven pens/block and received a diet of either 14%, 18% or 24% CP (n = 3, 2 and 2 pens/block, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Growth performance and carcass characteristics of pigs administered recombinant porcine somatotropin during 30 to 110 kilogram live weight.

To determine growth performance during and after injection of recombinant porcine somatotropin (rpSt), crossbred Yorkshire gilts and barrows (n = 54/gender, 27 to 42 kg BW) were blocked by BW and gender (n = 3 blocks/gender). Within each block, three pigs/gender were assigned randomly to each of six pens/block. A diet containing 24.8% CP was fed ad libitum. During the live weight period of 30 to 110 kg, pigs either remained as controls (one pen/block) or were injected (i.m.) daily with rpSt (120 micrograms/kg BW) during either 30 to 60, 30 to 100, 30 to 110, 60 to 100 or 60 to 110 kg BW. Thus, three gilts and three barrows in each of three pens received each treatment. Pigs were slaughtered at either 60 kg BW (1 d after rpSt injection) or 110 kg BW (1 d, 10 d or 70 d after rpSt injection). Relative to controls, pigs injected with rpSt exhibited faster and more efficient growth during the injection period (P less than .05) but slower and less efficient growth during 10 d after cessation of injection (P less than .05). Carcasses of pigs slaughtered 1 d or 10 d after rpSt injection were leaner than controls (P less than .05), but among the pigs treated with rpSt, carcasses of pigs withdrawn from rpSt for 10 d contained more fat (P less than .05) and had a lower percentage of muscle (P less than .05) than carcasses of pigs withdrawn from rpSt for 1 d. Growth and carcass measurements were similar (P greater than .05) between controls and pigs killed 70 d after rpSt injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Synchronization of estrus with melengestrol acetate and prostaglandin F2 alpha in beef and dairy heifers.

Beef (n = 783) and dairy (n = 209) heifers at 14 locations were used to evaluate the efficacy of feeding melengestrol acetate (MGA; .5 mg/d) for 7 d followed by an i.m. injection of 25 mg prostaglandin F2 alpha (PGF) on the last day of MGA feeding (MGA + PGF) to synchronize estrus. Untreated heifers (C) and heifers injected once i.m. with PGF served as contemporary controls. Heifers were observed for estrual behavior for a minimum of 38 d starting on the 2nd d of MGA feeding. Heifers in estrus from d 1 through d 60 after PGF injection were artificially inseminated (AI) or bred to bulls (d 30 to 60 post PGF only). During the 7-d MGA feeding period fewer (P less than .01) MGA + PGF (1.5%) than C (20.6%) or PGF (18.1%) heifers were observed in estrus. Percent of heifers in estrus d 1 to 6 post PGF was different among groups (P less than .05; 30.5, 52.8, 72.3 for C, PGF and MGA + PGF, respectively). More (P less than .01) MGA-fed (92%) than non-MGA-fed (C and PGF combined) heifers (85.4%) were observed in estrus during d 1 to 24. Conception rate (CR) during d 1 to d 6 was not different (P = .19) between C (58.9%) and MGA + PGF (51.2%) heifers; CR was lower (P = .01) for MGA + PGF than for PGF (68.3%) heifers.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbiological determination of neomycin in feeds: collaborative study.

A modification of the AOAC microbiological determination of neomycin in feeds was collaboratively studied by 12 laboratories. The official method was modified by substituting a constant salt concentration diluent for the feed extract diluent, preparing the agar medium in tris buffer, and performing the test with a monolayer plating system. Each laboratory performed single assays on 8 samples in a randomized sequence. The samples included duplicates of a cattle and swine feed at 2 different marketed concentrations. The mean recovery across all laboratories was 110.7% of theory with a range of means of 69.4-128.6 across the 12 laboratories. The results of one laboratory and 2 additional values from different laboratories were deemed outliers and excluded from statistical analysis. The statistical analysis gave a confidence interval of +/- 26% for individual assays.

Response of dogs to subcutaneous injections of various concentrations of propylene glycol with water.

Each of 85 dogs was injected, subcutaneously, with 5 different mixtures of propylene glycol (PG) and aqueous vehicles. Each dog was observed for immediate (within 15 minutes) and delayed (at 24, 48, and 72 hours) reactions. The reactions were classified as none, mild, moderate, and severe for the different observation periods. The study indicated that a mixture containing between 20% and 50% PG caused the fewest immediate reactions and that the number of delayed reactions increased as the proportion of PG in the solutions increased. Viscosity of the mixture also should be considered when selecting a vehicle.

Efficacy of lincomycin-spectinomycin water medication on Mycoplasma meleagridis airsacculitis in commercially reared turkey poults.

A field trial was conducted to compare the efficacy of a combination of the drugs lincomycin and spectinomycin (LS) with Tylan (tylosin, T) against Mycoplasma meleagridis (MM) airsacculitis in 50,320 commercially reared turkey poults in Ohio. Both drugs were administered at 2 g per gallon of drinking water for the first 5 days of life. The poults were allotted randomly to two treatment groups with 8 or 5 replicates each. Initially, 250 poults were weighed, necropsied, and examined microbiologically and grossly for airsacculitis. At 3 weeks of age, 33 poults from each replicate were randomly selected, necropsied, and examined for airsacculitis. The data indicate that LS is superior to T as an aid in the control of MM airsacculitis in poults, as reflected by fewer air-sac lesions and greater improvement in weight gain (P less than 0.05).

Effects of mibolerone on conception, pregnancy, parturition, and offspring in the Beagle.

Mibolerone was administered to Beagle bitches at dose levels of 20 or 60 microgram/day, starting 1,3, or 6 days after the 1st breeding and continuing until the offspring were weaned. Adverse effects on conception, pregnancy, or parturition were not observed in the treated bitches. Female offspring were masculinized. There were no gross effects on the male offspring.

Effects of organic phosphate systemic insecticides on bovine embryonic survival and development.

Experiments were conducted to determine effects of 2 organic phosphate systemic insecticides on embryonic survival and possible teratogenesis in cattle. A total of 726 heifers at 3 locations were treated with either crufomate (4-tert-butyl-2-chlorophenyl methyl methylphos-phoramidate) or coumaphos (O,O-diethyl O-(3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl) phosphorothioate). The compounds were administered to pregnant bovine females at various stages of gestation by pouring along the dorsal midline. None of the treatments, including those at recommended one-time doses, one-time doses at double or triple the recommended dose levels, or doses at recommended one-time dose levels repeated each day for 10 days, gave evidence of increasing embryonic death rates or of teratogenic effects. In one experiment, the crufomate compound had apparent erratic effects on serum ace5ylcholinesterase activities, but no effects on electrocardiographic patterns, heart rate, or respiration rate. Rectal palpation for pregnancy determination during the 35- to 44-day stages of pregnancy is discussed as a possible, but unsubstantiated, cause of congenital malformation of the caudal portion of the intestinal tract in 1 calf born during these studies and in other calves previously observed.