Parainfluenza-3 virus exposure of beef heifers prior to natural breeding.

Ninety-six Hereford heifers (approximately 7 months of age) were randomly divided into 2 equal groups and housed 1.6 km apart (with 2 replications in time, 1 year apart). At 15 months of age, 1 group/replicate was inoculated with parainfluenza-3 virus, and the other group was given virus-free spent culture medium. Twenty-four hours later, 2 virgin bulls (2 years old) were placed with each group (24 cows) for natural breeding. Viral inoculation caused a twofold increase in parainfluenza-3 titer and a 0.3 C body temperature increase. There was no effect recognized from the virus on natural breeding efficiency.     

Cross reactions of normal bovine sera with foot-and-mouth disease virus: incidence, duration, and effect of shipping stress.

Serum samples were obtained from 30 Hereford steers in an area known to be free of foot-and-mouth disease (FMD) viruses as follows: before shipment and 4 times during a 70-day period after shipment; the sera were tested for the presence of cross-reacting antibody to various viruses. Percentages of sera containing cross-reacting antibody to FMD virus detected by the plaque-reduction neutralization and the radial immunodiffusion techniques were higher for the FMD viruses Asia and SAT I5 than for the FMD viruses A5, O1, and C1. Cross-reacting antibody was usually of low titer and usually present in only 1 or 2 consecutive serum samples. The incidence of cross reactions increased after stress of shipping and thus an infective agent may be responsible. These results were compared with results from sera collected from Herefords and Holstein-Friesians in a 2nd area; results did not indicate that Herefords have an excess of cross reactions with FMD viruses.     

Isolation and identification of a bovine adenovirus type 3 with an adenovirus-associated virus.

A bovine adenovirus with agglutinating activity was isolated from feedlot calves and classified as serotype 3. The agglutinating activity was shown to be the property of an adenovirus-associated virus (AAV). The AAV was isolated from the bovine adenovirus by isopycnic centrifugation in CsCl; the AAV had a density of 1.4 g/cm2. This AAV is serologically related to bovine AAV-TR-15, but is distinct from bovine parvovirus-1 and primate AAV types 1 to 4, using counterimmunoelectrophoresis and hemagglutination-inhibition.     

The action of sulphanilamide on shell deposition

1. The action of sulphanilamide on egg shell deposition has been studied in the domestic fowl. The length of time that eggs remain in the shell gland was measured; the relative thickness and protoporphyrin pigment concentration for egg shells removed from the shell gland were determined; egg shell structure was examined using a replica technique.

2. Sulphanilamide appeared to act mainly by reducing the rate of shell deposition, time spent in the shell gland was unaffected.

3. The thickness of shell components was reduced in a roughly proportional manner in thin shells produced during sulphanilamide treatment.

4. It is proposed that other thin shells in which the component layers are all reduced to a similar extent are also the result of a decreased deposition rate.     

Sire × hatch interaction effects and pen effects in progeny testing broiler males for growth rate

1. Pen effects and sire x hatch interaction effects on growth rate to 8 weeks of age were estimated from family and progeny test data obtained from the application of two commercial breeding programmes for growth rate to broilers.

2. The following variance components were obtained: σ²(pen) = 255 g², σ²(sire) = 1 260 g², σ²(sire × hatch) = 1 997 g²,σ²(residual) = 19 708 g².

3. It is concluded that the effectiveness of progeny testing for growth rate in broilers is severely restricted by sire x hatch interaction effects.     

The use of n‐paraffin‐grown yeast as the main source of protein in diets for chicks

1. n‐Paraffin‐grown yeast and a mixture of soyabean meal and fish meal were compared in the net protein utilisation (NPU) test, and as protein supplements in diets for broilers up to 4 weeks of age.

2. The difference between the NPU values, 0.66 for yeast and 0.80 for the soyabean meal and fish meal mixture, could largely be attributed to the high nucleic acid content of the yeast.

3. Chicks given the diet containing yeast (190 g/kg) did not grow as rapidly as those given the soyabean meal and fish meal reference diet, and the reduced growth could only partly be explained by a marginal deficiency of methionine.

4. Food conversion efficiency with the yeast diet was improved by maize oil while responses to α‐tocopheryl acetate and sodium selenite were inconsistent.

5. Chicks grew well when yeast replaced fish meal in the mixture of soyabean meal and fish meal, and when fish meal (194 g/kg diet) was the sole protein supplement.     

The effects of low voltage current on healing of thermal third degree wounds.

Bilateral third degree burns were created on the flanks of eight miniature swine. Each animal had one side treated daily with low intensity direct (LIDC) of 400 microamperes (muA) by contact electrode for 2 hours morning and afternoon until healing occurred. The polarity of the electrode was negative in 4 pigs and positive in 4 pigs. One group of 4 pigs had the eschar surgically removed 24 hours post burn. Weekly biopsies and cultures were taken of treated and control wounds. Results indicated: local treatment of 400 muA LIDC did not hasten or delay healing of thermal third degree burns; escharectomy hastened wound healing by 10 days, and superficial proteus infection occurred in 80% of all wounds.