Hunting or habitat degradation? Decline of primate populations in Udzungwa Mountains,Tanzania: An analysis of threats

Hunting and habitat degradation are universal threats to primates across the tropics, thus deciphering the relative impact of threats on population relative abundance is critical to predicting extinction risk and providing conservation recommendations. We studied diurnal primates over a period of nearly 6 years in the Udzungwa Mountains of Tanzania, a site of global importance for primate conservation. We assessed how population relative abundance of five species (of which two are endemic and IUCN-Endangered) differed between two forest blocks that are similar in size and habitat types but contrast strongly in protection level, and how abundance changed during 2004–2009. We also measured habitat and disturbance parameters and, in the unprotected forest, evaluated hunting practices. We found significant differences in primates’ abundance between protected and unprotected forests, with the greater contrast being the lower abundance of colobine monkeys (Udzungwa red colobus and Angolan colobus) in the unprotected forest. At this site moreover, colobines declined to near-extinction over the study period. In contrast, two cercopithecines (Sanje mangabey and Sykes’ monkey) showed slightly higher abundance in the unprotected forest and did not decline significantly. We argue that escalating hunting in the unprotected forest has specifically impacted the canopy-dwelling colobus monkeys, although habitat degradation may also have reduced their abundance. In contrast, cercopithecines did not seem affected by the current hunting, and their greater ecological adaptability may explain the relatively higher abundance in the unprotected forest. We provide recommendations towards the long-term protection of the area.     

A meta-analysis comparing the effect of vaccines against Mycoplasma hyopneumoniae on daily weight gain in pigs

Our aims were to evaluate the published literature concerning the effect of swine vaccination against Mycoplasma hyopneumoniae on the average daily weight gain (ADWG). This was done by re-evaluating the influence of selected factors on ADWG by a meta-analysis of published studies from 1991 to 1999, fulfilling certain inclusion criteria.With ADWG as the outcome, an analysis of variance was performed for such variables as treatment, vaccination schedule, age during study, housing system and publication quality. Each clinical trial was considered as a random effect and the numbers of pigs in each trial were weightings.Of 63 published studies, 16 describing three commercial vaccines fulfilled the criteria for the meta-analysis. Due to few studies with one of the vaccines (n=3), only two vaccines were included.Vaccinated pigs gained an average of 592g (S.E.=15) with Stellamune and 590g (S.E.=15) with Suvaxyne compared to non-vaccinated pigs that gained an average of 569g (S.E.=14)(P<0.01) when adjusted for age during the study. Vaccine type, vaccination schedule, housing system and publication quality were not significantly associated with ADWG.     

Progression of Mycoplasma hyosynoviae infection in three pig herds. Development of tonsillar carrier state, arthritis and antibodies in serum and synovial fluid in pigs from birth to slaughter

In this investigation, natural infection with Mycoplasma hyosynoviae was followed in groups of individual pigs in three different herds with regard to occurrence of tonsillar carrier state, clinical arthritis and development of antibodies in serum and in synovial fluid. Antibodies were detected by a polyclonal enzyme-linked immunosorbent assay (ELISA) developed for experimental use. The infection with M. hyosynoviae progressed very differently in the three herds investigated. In one herd, the infection was apparently limited to adult pigs. In a second herd, all pigs became tonsillar carriers of M. hyosynoviae, but no mycoplasma-related arthritis nor any serological response was demonstrated within the growing-finishing period. In the third herd investigated, tonsillar infection was detected in all pigs, clinical cases of M. hyosynoviae arthritis followed and a moderate serological response was observed in some, but not all, pigs. In all three herds, M. hyosynoviae infection was carried in the tonsils of the adult pigs, but it was only occasionally transmitted from sows to piglets. Maternal antibodies were transferred to the piglets and persisted for approximately 8-12 weeks. After weaning, some pigs became infected before 20 weeks of age, while others did not. In the majority of cases, the tonsillar infection was established from 11 weeks of age or older. A latent tonsillar infection was present for a period of several weeks within the group of investigated pigs before cases of generalized infection and arthritis were seen. In some cases, generalization of M. hyosynoviae infection in the blood and in joints was observed in spite of the detection of an active serological response a few weeks earlier. The present work suggests that generalization of the infection and development of arthritis may depend on age, immunity, virulence factors and/or infection pressure; in some herds maybe combined with certain triggering mechanisms such as stress and lowered general resistance.     

Lymphoproliferation in captive wild ruminants affected with malignant catarrhal fever: 25 cases (1977-1985)

The severity of lymphoproliferative disease associated with malignant catarrhal fever was extremely variable among 25 animals at the San Diego Wild Animal Park. Severe lymphoproliferative disease was seen in 3 of 10 Formosan Sika deer (Cervus nippon taiouanus), 3 of 6 Indian Axis deer (Cervus a axis), 3 of 6 Barasingha deer (Cervus d duvauceli), and 1 of 3 Nilgai (Boselaphus tragocamelus). Two Sika deer and 2 Barasingha deer had lesions morphologically indistinguishable from lymphosarcoma. Our findings were consistent with the hypothesis that alcelaphine herpesvirus-1 has oncogenic potential.     

A "dipstick" enzyme immunoassay for detection of antibody to Brucella abortus in cattle sera.

An enzyme immunoassay that utilizes antigen bound to a matrix which can be removed from the substrate to stop development is described. The assay which is performed in glass or plastic disposable tubes uses Gel-Bond film strips for attachment of antigen. The only equipment requirements are a rotary shaker and a spectrophotometer (optional). The antigen coated strips are passed through a series of tubes containing test serum, wash solution, antibody-enzyme conjugate, wash solution and substrate-chromogen taking about 45 minutes to perform. In testing sera with or without antibody to Brucella abortus a very high correlation existed between same day tests and tests performed over several days as well as with data on the same sera obtained by an enzyme immunoassay in a microtiter format.     

Haemophilus pleuropneumoniae (Actinobacillus pleuropneumoniae). Serotypes 8, 3 and 6. Serological response and cross immunity in pigs

Immunity obtained by vaccination with Haemophilus pleuropneumoniae is type specific and protection will only be obtained against the serotype contained in the vaccine. Serotype 8 is closely related to serotypes 3 and 6 and the objective of the present study was therefore to examine if cross immunity between the three serotypes could be obtained at vaccination.     

Bone strength of laying hens kept in an alternative system, compared with hens in cages and on deep-litter

1. Observations of vigorous wing movements and measurements of bone strength were compared in two experiments with birds in three different housing systems: a semi-intensive alternative system under development, a battery cage system and a deep-litter system. 2. A significant effect of housing system on the frequency of vigorous wing movements was found. The highest frequency was seen in the deep-litter system, about half this number in the alternative system, while in the battery cages they were never observed. 3. Corresponding to this a reduction in humerus strength of 9% was found in hens from the alternative system and of 45% in hens from cages, compared with deep-litter. A reduction in tibial breaking strength was also found in caged hens, when compared to deep-litter hens. 4. Keeping hens in cages thus restricts their movements, especially wing movements, to the degree that bone strength is greatly reduced. 5. This has welfare implications, for hens with low bone breaking strength risk a possibility of breakage, especially when handled and transported. When alternative systems are designed opportunities for movement in the three dimensions should be considered.     

Alternative methods of selection for litter size in mice: II. Response to thirteen generations of selection

Selection was conducted on an index of components of litter size (I = 1.21 x ovulation rate + 9.05 x ova success; ovulation rate measured by number of corpora lutea and ova success measured as number of pups born + number of corpora lutea), on uterine capacity (measured as number of pups born to unilaterally ovariectomized dams) and on litter size concurrent with an unselected control for 13 generations. Selection criteria (IX = index, UT = uterine capacity, LS = litter size and LC = control) were applied in each of three replicates. In an evaluation after five generations, IX and LS each exceeded LC by about .5 pups, with no response in UT. After 13 generations, mean ovulation rate, ova success and litter size (measured as number of fetuses at 17 d gestation in intact females) were, for IX, 14.25, .84, 11.95; for LS, 14.15, .82, 11.64; for UT, 12.61, .86, 10.77; and for LC, 12.27, .82, 9.98. The regression of number born (litter size in IX, LS and LC; uterine capacity with only a functional left uterine horn in UT) on cumulative selection differential across 13 generations was .12 +/- .01, .09 +/- .02 and .08 +/- .02 for IX, LS and UT, respectively. The regression of breeding value for litter size on each selection criterion, estimated as response in the generation-13 evaluation divided by cumulative selection differential, was .11 +/- .02, .08 +/- .01 and .05 +/- .03 for IX, LS and UT, respectively. Regression of response in number born on generation number was .17 +/- .01, .15 +/- .04 and .10 +/- .02 for IX, LS and UT, respectively. Selection in IX was promising relative to LS, and selection in UT changed number born.