Colour‐Doppler ultrasound imaging as a laparoscopy substitute to count corpora lutea in superovulated sheep

This study evaluated colour‐Doppler ultrasound imaging (UI) as a substitute for laparoscopy to count the corpora lutea (CL) in superovulated sheep. Twenty‐five Santa Ines ewes were superovulated three times at 21‐day intervals. Corpora lutea were counted by colour‐Doppler UI (CL_DOPPLER) 6 days after each superovulation and confirmed by laparoscopy (CL_LAP) 12 hr later. The mean number of CL was similar for both techniques (2.1 ± 2.5 vs. 2.1 ± 2.7 for CL_DOPPLER and CL_LAP, respectively) with a significant positive correlation (r = .94; r²=.89). Colour‐Doppler UI effectively evaluated the ovarian response in superovulated ewes and efficiently identified animals that did not respond to superovulation.     

Elimination of bovine viral diarrhoea virus in New Zealand: a review of research progress and future directions

The major impacts of bovine viral diarrhoea (BVD) on cattle health and production have prompted many countries to embark on national elimination programmes. These programmes typically involve identifying and removing persistently infected (PI) cattle in infected herds and implementing biosecurity measures, such as pre- or post-movement testing. In order to design a systematic national control programme to eliminate BVD in New Zealand, which achieves the greatest benefits to the industries at the lowest cost to individual farmers, an accurate understanding is necessary of the epidemiology, economics and social motivation for BVD control in New Zealand. In this article we briefly review the pathogenesis of BVD, transmission and diagnosis of BVD virus infection, and effectiveness of vaccination. We summarise the current state of knowledge of the prevalence, risk factors for transmission, and financial impacts of BVD in New Zealand. We describe control programmes in Europe and then discuss the challenges that must be addressed to design a cost-effective national control programme to eliminate BVD in New Zealand.     

Pre‐Selection Test to Identify High Responder Donor Goats

The aim of the study was to evaluate the feasibility of pre‐selection of high or low responder does prior to the superovulatory protocols. Twenty Saanen does received 800 IU of equine chorionic gonadotropin (eCG) at the end of long‐term progestogen treatment. Fourteen days later, a second progestogen protocol associated with a multiple‐dose follicle stimulation hormone (FSH) treatment (5 IU/kg of FSH, in six decreasing doses between days 4 to 6 of the protocol) was administered. Transrectal ultrasound was used to assess the follicular status at the beginning of superovulatory treatments, at the oestrous onset and on the seventh day of the oestrous cycle for counting corpora lutea (CL). A significant lower number of CL was obtained in eCG‐treated in comparision with FSH‐treated does (p < 0.05). A quartic regression was able to explain the relationship between the number of CL in response to both treatments (r²=0.50; p < 0.05). Seventy per cent (14 of 20) of does maintained the same ovulatory response (high or low) after treatments. The Kappa (κ = 0.40; p < 0.05) and Spearman (rs = 0.39; p = 0.08) coefficients were able to show a relationship between treatments. Regarding the follicular status, there is a significant relationship between the number of small follicles (r = 0.71; r²=0.47; p < 0.01) and total follicles (r = 0.60; p < 0.01) at eCG and first FSH dose with the number of CL. Moreover, it was found a negative relationship between the presence of large follicles and the number of CL in response to eCG treatment (r = ?0.44; p < 0.05), but not from FSH (p > 0.05). In conclusion, the screening test with eCG has the potential to identify Saanen does that will better respond to the superovulatory protocol with FSH. In addition, it highlighted the importance of an ultrasound evaluation prior to the beginning of superovulatory treatments with FSH to characterize the follicular status and identify the potential donors of high ovulatory response in MOET programmes in goats.     

Naturally acquired antibodies to Bacillus anthracis protective antigen in vultures of southern Africa

Sera from 19 wild caught vultures in northern Namibia and 15 (12 wild caught and three captive bred but with minimal histories) in North West Province, South Africa, were examined by an enzyme-linked immunosorbent assay (ELISA) for antibodies to the Bacillus anthracis toxin protective antigen (PA). As assessed from the baseline established with a control group of ten captive reared vultures with well-documented histories, elevated titres were found in 12 of the 19 (63%) wild caught Namibian birds as compared with none of the 15 South African ones. There was a highly significant difference between the Namibian group as a whole and the other groups (P < 0.001) and no significant difference between the South African and control groups (P > 0.05). Numbers in the Namibian group were too small to determine any significances in species-, sex- or age-related differences within the raw data showing elevated titres in four out of six Cape Vultures, Gyps coprotheres, six out of ten White-backed Vultures, Gyps africanus, and one out of three Lappet-faced Vultures, Aegypius tracheliotus, or in five of six males versus three of seven females, and ten of 15 adults versus one of four juveniles. The results are in line with the available data on the incidence of anthrax in northern Namibia and South Africa and the likely contact of the vultures tested with anthrax carcasses. It is not known whether elevated titre indicates infection per se in vultures or absorption of incompletely digested epitopes of the toxin or both. The results are discussed in relation to distances travelled by vultures as determined by new tracking techniques, how serology can reveal anthrax activity in an area and the issue of the role of vultures in transmission of anthrax.     

Plasticity in mesophyll volume fraction modulates light-acclimation in needle photosynthesis in two pines

Acclimation potential of needle photosynthetic capacity varies greatly among pine species, but the underlying chemical, anatomical and morphological controls are not entirely understood. We investigated the light-dependent variation in needle characteristics in individuals of Pinus patula Schlect. & Cham., which has 19-31-cm long pendulous needles, and individuals of P. radiata D. Don., which has shorter (8-17-cm-long) stiffer needles. Needle nitrogen and carbon contents, mesophyll and structural tissue volume fractions, needle dry mass per unit total area (M(A)) and its components, volume to total area ratio (V/A(T)) and needle density (D = M(A)/(V/A(T))), and maximum carboxylase activity of Rubisco (V(cmax)) and capacity of photosynthetic electron transport (J(max)) were investigated in relation to seasonal mean integrated irradiance (Q(int)). Increases in Q(int) from canopy bottom to top resulted in proportional increases in both needle thickness and width such that needle total to projected surface area ratio, characterizing the efficiency of light interception, was independent of Q(int). Increased light availability also led to larger M(A) and nitrogen content per unit area (N(A)). Light-dependent modifications in M(A) resulted from increases in both V/A(T) and D, whereas N(A) changed because of increases in both M(A) and mass-based nitrogen content (N(M)) (N(A) = N(M)M(A)). Overall, the volume fraction of mesophyll cells increased with increasing irradiance and V/A(T) as the fraction of hypodermis and epidermis decreased with increasing needle thickness. Increases in M(A) and N(A) resulted in enhanced J(max) and V(cmax) per unit area in both species, but mass-based photosynthetic capacity increased only in P. patula. In addition, J(max) and V(cmax) showed greater plasticity in response to light in P. patula. Species differences in mesophyll volume fraction explained most of the variation in mass-based needle photosynthetic capacity between species, demonstrating that differences in plastic adjustments in mass-based photosynthetic activities among these representative individuals were mainly associated with contrasting investments in mesophyll cells. Greater area-based photosynthetic plasticity in P. patula relative to P. radiata was associated with larger increases in M(A) and mesophyll volume fraction with increasing irradiance. These data collectively demonstrate that light-dependent increases in mass-based nitrogen contents and photosynthetic activities were associated with an increased mesophyll volume fraction in needles at higher irradiances. They also emphasize the importance of light-dependent anatomical modifications in determining needle photosynthetic capacity.     

Increased photosynthesis following partial defoliation of field-grown Eucalyptus globulus seedlings is not caused by increased leaf nitrogen

Increased photosynthetic rates following partial defoliation may arise from changes in leaf biochemistry, water relations or nutrient status. Twelve-month-old field-grown Eucalyptus globulus Labill. seedlings were pruned from below to reduce the green crown depth by 50 (D50) or 70% (D70). Photosynthetic responses to light and CO2 concentration were examined before and one, three and five weeks after partial defoliation. One week after defoliation, photosynthetic rates were greater in seedlings in the D50 (21 micromol m(-2) s(-1)) and D70 (23 micromol m(-2) s(-1)) treatments than in control seedlings (15 micromol m(-2) s(-1)); however, there was little difference in photosynthetic rates between partially defoliated seedlings and control seedlings after 5 weeks. An analysis of the sensitivity of photosynthesis to biochemical parameters revealed that the transient increase in photosynthetic rate in response to partial defoliation was largely a function of the maximum rate of carboxylation (85-87%) and the maximum rate of RuBP regeneration (55-60%) rather than stomatal conductance (12-13%). Nitrogen increased in leaves following partial defoliation (increases of 0.6 and 1.2 g m(-2) for D50 and D70, respectively), but was accumulated in a non-photosynthetic form (i.e., there was no increase in nitrogen concentration of Rubisco or chlorophyll). Increased photosynthetic rates immediately following partial defoliation were primarily a result of increased activity rather than amount of photosynthetic machinery. There was no evidence that phosphorus was responsible for the increase in photosynthetic rates after partial defoliation.