Review of morphological and behavioural differences between reared and wild individuals: Implications for sea-ranching of Atlantic salmon, Salmo salar L., Atlantic cod, Gadus morhua L., and European lobster, Homarus gammarus L.

Abstract The main question which must be raised when planning to enhance natural populations through sea ranching is whether reared organisms are fit for a life in the wild, or more specifically, whether there are differences between reared and naturally resident individuals. The causes and effects of these differences are reviewed, and results from the Norwegian enhancement programme, which compared reared and wild individuals of Atlantic salmon, Salmo salar L., Atlantic cod, Gadus morhua L., and European lobster, Homarus gammarus L., are discussed with emphasis on morphological and behavioural differences. It was concluded that exposure to an artificial rearing environment during ontogeny can affect both the phenotype and the behaviour of the reared individuals, and thereby, their potential for survival after release into the wild as well. Suggestions are made as to how to diminish observed differences, and thereby, improve the survival potential.     

Multinuclear–Multiflagellar Sperm Defect in a Bull – a New Sterilizing Sperm Defect

The development and use of modern techniques, such as intracytoplasmic sperm injection (ICSI), gene knockout and sperm fluorescence in situ hybridization with chromosome- specific probes, have significantly increased our knowledge about sperm defects. We describe a new oligoasthenoteratozoospermic defect in a bull. Because of its morphological characteristics the defect was named the multinuclear-multiflagellar sperm defect. All spermatozoa in the ejaculate were abnormal. Many of the spermatozoa had multiple nuclei and multiple sperm tails. All spermatozoa lacked an acrosome, and only seldom did spermatozoa have a mitochondrial helix in the midpiece area. Meiosis and spermiogenesis were severely affected in this otherwise phenotypically normal bull. The sperm defects resembled the phenotype of a targeted gene knockout Hrb(-/-) (HIV-1 Rev-binding/interacting protein) mutant mouse strain, which is expressed as sterility in males, while females remain fertile. Since the father of this bull has been extensively used in at least three countries the defective gene has possibly become widespread in the red and white breeds (Ayrshire, Swedish Red and White, Norwegian Red) in the Nordic countries. However, it is not proved that the father of this bull is a carrier of this defect.     

Fertility of Holstein cows and heifers submitted to timed artificial insemination and receiving one or two doses (12 h apart) of semen

The objective of this retrospective study was to assess the effect of receiving a single (n = 50,285) or double (n = 4392) artificial insemination (AI), 12 h apart, within a timed artificial insemination protocol on pregnancy per AI (P/AI) in nulliparous heifers (inseminated with either sex-sorted or conventional semen) and pluriparous Holstein cows in a commercial dairy herd. Also, this study aimed to investigate the relationship between temperature-humidity index (THI) and time of the first AI and fertility. Fertility of cows receiving two AI with normothermia (THI <68) was higher (p < .05) than cows receiving a single AI (42.9% vs. 36.4%). P/AI of cows receiving two AI with severe heat stress (THI >85) was higher (p < .05) than cows receiving a single AI (21.0% vs. 12.6%). Regardless of heat stress conditions, applying the first AI in the morning increased (p < .05) P/AI in cows with double AI than in cows whose first AI occurred in the afternoon (38.4 vs. 33.3%). With moderate heat stress, and sexed-sorted semen, P/AI to timed AI was higher (65.0 vs. 51.9%; p < .05) in heifers receiving double AI than those serviced once. It was concluded that double AI, 12 h apart, enhanced fertility at timed AI than herd mates with a single AI, particularly with heat stress at breeding.     

Susceptibility of adult chickens, with and without prior vaccination, to challenge with Marek's disease virus

Marek's disease (MD) outbreaks can occur in previously healthy adult layer or breeder flocks. However, it is not clear whether such outbreaks are caused by recent challenge with highly virulent (vv and vv+) strains of MD virus (MDV; i. e., new infection hypothesis) or by exacerbation of an earlier MDV infection (i. e., old infection hypothesis). To discriminate between these hypotheses, adult White Leghorn chickens of laboratory strains or commercial crosses with or without prior vaccination or MDV exposure were challenged at 18-102 wk of age with highly virulent MDVs, and lesion responses were measured. Horizontal transmission was studied in one trial. Challenge of adult chickens, which were free from prior MDV vaccination or exposure, with highly virulent MDV strains induced transient paralysis or tumors in 60%-100% of 29 groups (mean = 91%), and horizontal spread of virus was detected. The magnitude of the response was similar to that induced by challenge at 3 wk of age. In contrast, comparable challenge of adult chickens, which had been vaccinated or exposed to MDV early in life, induced transient paralysis or tumors in 0%-6% of 12 groups (mean = 0. 5%), although some birds showed limited virologic evidence of infection and transmission of the virus to contacts. The MD responses were influenced by the virulence of the challenge virus strain, and to a lesser extent by virus dose and route of exposure. Strong inflammatory lesions were induced in the brain and nerves of adult specific pathogen-free (SPF) chickens at 9-15 days after infection. The low susceptibility of previously vaccinated and exposed groups to challenge at > or =18 wk of age suggests that late outbreaks of MD in commercial flocks are not likely a result of recent challenge alone and that additional factors could be involved.     

Breeding objectives of Brangus cattle in Brazil

Our goal was to define a breeding objective for Brangus beef cattle in Brazil. Bioeconomic models were produced and used to estimate economic values (EVs). The scenarios simulated were typical full-cycle beef production systems that are used in tropical and subtropical regions. The breeding objective contained pregnancy rate (PR), warm carcass weight (WCW), mature cow weight (MCW), number of nematode eggs per gram of faeces (EPG) and tick count (TICK). Two models were used in series to estimate the EV. A deterministic model was used to simulate effects of PR, WCW and MCW on profitability with a constant parasite load. Subsequently, stochastic models were used to estimate economic values for TICK and EPG as consequences of their environmental effects on weight gains, mortality and health costs. The EV of PR, WCW, MCW, EPG and TICK, was US$1.59, US$2.11, −US$0.24, −US$5.35 and −US$20.88, respectively. Results indicate positive emphasis should be placed on PR (12.49%) and WCW (65.07%) with negative emphasis on MCW (13.92%), EPG (2.77%) and TICK (5.75%). In comparison with the indexes usually used, these results suggest a reformulation in the selection indexes of the beef production system in tropical and subtropical regions in order to obtain greater profitability.     

Pheromone-based communication disruption ofAdoxophyes orana on peach using the new RAK 3+4 dispensers and their effect on development of fruit rot diseases

The effectiveness of the pheromone-based communication disruption method was examined against the summerfruit tortrix,Adoxophyes orana F.v.R. (Lepidoptera: Tortricidae), a pest of peach trees, using the new RAK 3+4 dispenser (BASF). NoA. orana males were captured in pheromone traps inside the experimental orchards, which were saturated with the RAK 3+4 dispensers. The percent of damaged leaves was practically zero, while the level of damaged fruits was 0–6% in pheromone-treated orchards. The percentage of fruit rot caused byMonilinia laxa was lower in pheromone-based communication disruption orchards than in the control. It was concluded that the RAK 3+4 dispenser could be used againstA. orana as an economical and environmentally friendly method.     

Seroprevalence of Neospora caninum in dairy cattle in Bahia, Brazil.

Sera collected from 447 dairy cattle on 14 dairy farms were tested for Neospora caninum antibodies by use of an immunofluorescent antibody technique. Positive reactions with titres > or =1:200 were found in 63 (14.09%) of animals. Neospora positive sera were also tested for Toxoplasma gondii antibodies by using a commercial latex agglutination test. Antibodies to T. gondii were detected in 3 (4.76%) of 63 N. caninum positive sera. These results indicate that N. caninum infection is widespread among dairy cattle in Bahia state.