Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B

AIM: To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline.

METHODS: Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0–5) weekly during the study. Any animal which was scored ≥4 was removed from the study.

RESULTS: Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41).

CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.     

Cryopreservation of Piau‐Breed Wild Boar Sperm: Assessment of Cooling Curves and Centrifugation Regimes

This study aimed to assess the effects of different cooling curves and centrifugation regimes used in cryopreservation protocols on the post‐thaw viability of Piau‐breed wild boar (Sus scrofa) sperm using in vitro assessment tests. Two centrifugations (800  g for 10 min and 2400  g for 3 min) and two cooling curves (conventional cooling using nitrogen vapour – freezing 1 and automated cooling using a programmed freezing machine – freezing 2) were tested. Therefore, the treatments were divided into M3 – centrifugation at 2400  g for 3 min and freezing 2; M10 – centrifugation at 800  g for 10 min and freezing 2; R3 – centrifugation at 2400  g for 3 min and freezing 1; and R10 – centrifugation at 800  g for 10 min and freezing 1. No significant differences (p > 0.05) between treatments occurred post‐thawing regarding the total sperm motility means recorded. The mean values of the different treatments were not different from each other regarding the supravital staining (SV), hypo‐osmotic test (HO), sperm–egg binding assay or sperm morphology. This study showed that both the cooling curve and the centrifugation regime affected the quality of post‐thaw sperm, and centrifugation for shorter times and cooling curves using automated cooling are the most suitable for minimizing sperm injury.     

Cell Proliferation in the Atretic Follicles of Buffalo and Cattle Ovary

The present study was carried out to describe the proliferative activity of granulosa and theca cells in healthy antral and atretic follicles of Philippine buffaloes (BU) and Holstein-Friesian (HF) cows. Paraffin sections of ovary were immunostained with mouse monoclonal antibody to proliferating cell nuclear antigen (PCNA). Then the follicles were classified into healthy and various stages of atretic follicles. The granulosa layer of healthy follicles had a significantly higher frequency of PCNA-positive cells than the early and advanced atretic follicles in both breeds. In the theca interna, significantly reduced populations of the PCNA-positive cells were found in both breeds as atresia progressed. Moreover, HF had significantly higher PCNA-positive cells in the theca interna of healthy, early atretic and advanced atretic follicles than BU. A reduction of PCNA-positive cells during atresia was also noted in the theca externa in both animals although differences were not significant. The results of the present work suggest that the proliferative activity of granulosa and theca cells decreases in association with follicular atresia in the BU similar to HF. Furthermore, a significantly deficient cell proliferative activity of theca interna was found in BU compared with HF.     

Effects of barley variety fed to steers on carcass characteristics and color of meat

This study evaluated the effect of barley varieties in the diets of finishing steers on carcass composition, fat, and lean color and the fatty acid profile of subcutaneous fat. Crossbred steers (391 kg initial BW) were assigned randomly to one of five finishing diets composed primarily of corn (n = 9), Morex barley (n = 9), Steptoe barley, (n = 9), or two experimental barley varieties SM3 (n = 9) and SM5 (n = 9). Grains were cracked prior to feeding. Diets were formulated (DM basis) to be isonitrogenous (2.24% N) and isocaloric (2.01 Mcal/kg NEm and 1.35 Mcal/kg NEg). Steers were slaughtered according to industry-accepted procedures when it was visually estimated that 70% of carcasses would grade USDA Choice. After a 24-h chill at 4 degrees C, carcass quality and yield grade data were collected by trained, experienced university personnel. Objective color (L*, a*, and b*) of both the LM and subcutaneous fat were measured, and samples of subcutaneous fat were removed from the 10th- to 12th-rib region for fatty acid analysis. Diet did not affect hot carcass weight (P = 0.15), fat thickness (P = 0.58), LM area (P = 0.57), percentage of internal fat (P = 0.52), yield grade (P = 0.96), marbling (P = 0.73), or quality grade (P = 0.10). However, the LM from steers fed diets formulated with Morex and SM5 barley varieties tended to be lighter (higher L* values, P = 0.08) than the LM from steers fed the corn-based diet. Additionally, fat from steers fed corn tended to be more yellow (higher Hunter b* values, P = 0.09) than fat from steers fed barley-based diets. Although grain source had only minimal effects on the fatty acid composition of subcutaneous fat samples, pentadecanoic acid (15:0) was greater (P < 0.05) in fat from steers fed SM3 and Steptoe barley varieties than in fat from steers fed corn. Stearic acid (18:0) concentrations were higher (P < 0.05) in fat samples from steers fed corn than in those fed the experimental barley lines (SM3 and SM5). Conversely, fat samples from steers fed Steptoe and SM5 barley had greater (P < 0.05) gadoleic acid (20:1) concentrations than fat from steers fed corn or Morex variety. Although the variety/line of barley included in the finishing diet may affect LM and fat color, grain-source (barley vs. corn) had little effect on beef carcass quality and yield grades and did not greatly alter the fatty acid composition of subcutaneous fat.     

Impact of a catastrophic hurricane on island populations

Lizard and spider populations were censused immediately before and after Hurricane Lili on islands differentially affected by the storm surge. The results support three general propositions. First, the larger organisms, lizards, are more resistant to the immediate impact of moderate disturbance, whereas the more prolific spiders recover faster. Second, extinction risk is related to population size when disturbance is moderate but not when it is catastrophic. Third, after catastrophic disturbance, the recovery rate among different types of organisms is related to dispersal ability. The absence of the poorer dispersers, lizards, from many suitable islands is probably the result of long-lasting effects of catastrophes.     

Effectiveness of a non-surgical alternative to the Mules operation in sheep

Objective To measure changes to the perineal bare area, local tissue reaction and healing responses of young sheep, following intradermal administration of cetrimide and polyvinylpyrrolidone (PVP), with and without ethanol, to the breech and tail. Method A needle‐less injector was used to deposit formulations containing 40 g/L cetrimide and 30 g/L PVP (group 2) or 20 g/L cetrimide, 30 g/L PVP and 15 g/L ethanol (group 3), within the dermis of the tail and the region surrounding the perineal bare breech area of groups (N = 8) of Merino weaner sheep. The dimensions of the perineal bare area (length, width and diagonal distances left and right) and tail width were recorded before and at intervals after treatment for 60 days. Observations of swelling and bruising and scab formation at the treatment sites were recorded for up to 35 days after treatment. Rectal temperatures were monitored for up to 35 days after treatment and bodyweight for up to 60 days after treatment. An untreated control group (group 1) was included. Results Comparison of day ‐3 and day 35 measurement data showed that both treated groups had significantly (P < 0.05) wider breech bare areas compared to the untreated controls and that group 2 sheep had significantly (P < 0.05) longer breech bare areas compared to group 3 sheep or to the untreated controls, which were not significantly different. At this time scabs were still firmly in place on many treated sheep. At day 35 there was no increase in tail bare area caused by either treatment. By day 60 there was no significant difference between the treated and control groups in either the breech or tail regions indicating that the changes present at day 35, were not permanent. Mean weight gain in the groups throughout the 60‐day interval was unaffected by treatment. Intradermal treatment was associated with a significant elevation in body temperature. This effect lasted for 3 days and was associated with signs of discomfort and depressed appearance in at least some of the treated sheep. Bruising was mild to severe in all treated sheep within two days of treatment but was not evident in any sheep by day 21. Mild to moderate swelling was also associated with treatment but was not uniform across sheep in the groups. The tail of one sheep was severely swollen for several days. Swelling remained obvious in most treated sheep until day 14 but was not present at day 21. Conclusion Under the conditions of this study intradermal injection of cetrimide had no permanent effect on bare area measurements on the breech or the amount of wool‐bearing skin on the tail. It also caused signs of discomfort and pain that raise welfare concerns.     

Selenium hyperaccumulation offers protection from cell disruptor herbivores

Background  

Hyperaccumulation, the rare capacity of certain plant species to accumulate toxic trace elements to levels several orders of magnitude higher than other species growing on the same site, is thought to be an elemental defense mechanism against herbivores and pathogens. Previous research has shown that selenium (Se) hyperaccumulation protects plants from a variety of herbivores and pathogens. Selenium hyperaccumulating plants sequester Se in discrete locations in the leaf periphery, making them potentially more susceptible to some herbivore feeding modes than others. In this study we investigate the protective function of Se in the Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus against two cell disrupting herbivores, the western flower thrips (Frankliniella occidentalis) and the two-spotted spider mite (Tetranychus urticae).     

Effect of the Medium Replacement Interval on the Viability,Growth and In Vitro Maturation of Isolated Caprine and Ovine Pre‐Antral Follicles

The aim of the present study was to evaluate the effects of different medium replacement intervals on the viability, antral cavity formation, growth and in vitro maturation (IVM) of oocytes from caprine and ovine pre‐antral follicles. Pre‐antral ovarian follicles (≥150 μm) were isolated from the ovarian cortex of goats and sheep and were individually cultured for 24 days using two different medium replacement intervals [2 days (T₁) or 6 days (T₂)]. Follicle development was evaluated on the basis of antral cavity formation, increases in follicular diameter and the presence of healthy cumulus oocyte complexes and fully grown oocytes. For caprine species, results showed a higher percentage (p < 0.05) of viable follicles in T₁ than T₂ from day 6 until the end of the culture. In addition, when comparing both treatments after the same culture duration, the rate of antrum formation was significantly higher in T₁ than in T₂ from day 12 onwards. Yet, in ovines, when both treatments were compared on day 24 of the culture, there were more viable follicles in T₂ than in T₁ (p < 0.05). In the caprine species, percentages of fully grown oocytes (≥110 μm) acceptable for IVM after 24 days of culture were significantly higher in normal follicles cultured in T₁ (30.0%) than in T₂ (6.7%; p < 0.05). On the other hand, in ovines, at the end of the culture, the percentage of oocytes destined for IVM was higher in T₂ than in T₁ (23.5% vs 2.9%; p < 0.05). In conclusion, under the same conditions, the frequency of medium replacement significantly affected the in vitro development of caprine and ovine pre‐antral follicles. To improve the efficiency of the culture system, the medium must be replaced every 2 and 6 days for goat and sheep pre‐antral follicles, respectively.