A survey of northern Victorian dairy farmers to investigate dairy calf management: colostrum feeding and management

Objectives

To describe colostrum management practices carried out in northern Victorian dairy herds and to identify weaknesses in these areas that may affect calf health and welfare by comparing the results with the current industry recommendations

Methods

A questionnaire to obtain information about colostrum management and calf‐rearing practices was sent to commercial dairy farming clients of Rochester Veterinary Practice between June and September 2013. The questionnaire consisted of a general herd overview and colostrum harvesting practices.

Results

The response rate was 39% (58/150). Many dairy producers were not meeting the current industry recommendations in the following areas: (1) time of removal calf from the dam, (2) relying on calf suckling colostrum from the dam to achieve adequate passive transfer, (3) failing to supplement calves with colostrum, (4) feeding inadequate volumes of colostrum, (5) delayed colostrum harvesting, (6) pooling of colostrum, (7) failing to objectively assess colostrum quality or relying on visual assessment and (8) storing colostrum for a prolonged periods of time at ambient temperatures.

Conclusion

The results from this survey highlight the need for greater awareness of industry standards for colostrum management and feeding hygiene.

     

Die Bekämpfung des Kartoffelkäfers (Leptinotarsa decemlineata Say)

Ohne Zusammenfassung     

Total serum bile acid concentrations in dairy cows with fatty liver and liver failure

In forty-five Holstein Frisian dairy cows (1-6 weeks post partum; mean age: 5.1 +/- 1.2 years) the serum total bile acid concentrations (SBA) were measured enzymatically. In all cows a left sided abomasal displacement was corrected surgically by right side laparotomy and omentopexy three days before investigation. The liver fat content was determined in all cows histologically. Liver failure was assumed if typical clinical signs (ataxia, general depression, recumbency or coma), an increased venous plasma ammonia level (> 35 mumol/l) and a decreased plasma amino acid index (< 4.0) were found. Cows without liver failure (N = 29) were grouped according to the liver fat content as cows with mild (N = 5), moderate (N = 19) or severe hepatosteatosis (N = 5). Histological examination of liver biopsies in cows with liver failure (N = 16) revealed in twelve cases a severe fatty liver and in four cases a hydropic degeneration of the liver tissue. Although in cows without liver failure mean SBA concentrations were higher in the group with moderate (47.3 +/- 30.9 mumol/l) or severe fatty liver (32.9 +/- 21.7 mumol/l) than in that with mild lipidosis (18.0 (16.8 mumol/l), differences were not significant. The mean SBA concentration in cows with liver failure (70.5 +/- 49.5 mumol/l) was only significantly (p < 0.05) increased compared to cows with uncomplicated mild hepatic lipidosis. In conclusion, the determination of SBA concentrations is of little value in the recognition of fatty liver or even liver failure due to the considerable variance of SBA concentrations in dairy cows.     

Sulfidoleukotriene generation from peripheral blood leukocytes of horses affected with insect bite dermal hypersensitivity

Sulfidoleukotrienes (sLT) generated in vitro after incubation of equine peripheral blood leukocytes (PBL) with different inducing agents were determined in 18 healthy and 16 insect bite dermal hypersensitivity (IDH)-affected horses. PBL from these 32 horses were stimulated with Concanavalin A, Parascaris equorum, Culicoides nubeculosus and Simulium extracts, and with a six-Grass mix. The cells of all but four horses generated sLT after incubation with Concanavalin A; these four horses did also not produce sLT with the other inducing agents. Of the 28 remaining horses (12 affected with IDH and 16 healthy), all but three generated sLT with the P. equorum extract. The six-Grass mix did not induce sLT production in any of the tested horses. sLT generation with Concanavalin A and Parascaris was statistically not different between IDH-affected and healthy horses. PBL of the diseased horses, however, produced significantly more sLT with the Culicoides (p < 0.01) and Simulium (p < 0.05) extracts than those of the healthy animals. Additionally, sLT generation with the Culicoides extract was measured at different times of the year in one IDH-affected animal and remained high even in winter, when the horse was asymptomatic. sLT and histamine release were determined in 10 horses in parallel. Positive correlations of 0.81 and 0.82 for Concanavalin A and Parascaris (p < 0.01 and p < 0.05, respectively), and of 0.95 and 0.94 for Culicoides and Simulium (p < 0.01) were found between sLT and histamine release. These results indicate that, alike in humans, sLT are released in vitro from equine basophils along with histamine in response to various stimuli and that immediate type hypersensitivity reactions to Culicoides and Simulium are often involved in the pathogenesis of IDH. Thus, sLT generation from equine basophils offers an in vitro diagnostic tool for IDH even in sensitised but asymptomatic horses.     

Epidemiology of Fusarium Infection and Deoxynivalenol Content in Winter Wheat in the Rhineland, Germany

Details of our long-term research programme concerning the epidemiology of Fusarium spp. and mycotoxin production are summarized. Evaluation of the occurrence of Fusarium spp., mainly on winter wheat (Triticum aestivum), was carried out by investigating Fusarium infection and mycotoxin contamination. Two to 15% of grains were infested during 1995–1998 at three climatologically differing localities of the Rhineland, Germany. Disease progress was accelerated by rainfall during the flowering season. The species most frequently isolated were Fusarium avenaceum, F. poae, F. culmorum and F. graminearum. The mean deoxynivalenol (DON) content varied from 19gkg^–1 (1995) to 310gkg^–1 (1998) and was not always correlated with disease severity. Organic farming systems showed lower rates of infection with ear blight and lower mycotoxin contamination than conventional farming systems.     

Morphometry,Morphology and Ultrastructure of Ring‐tailed Coati Sperm (Nasua nasua Linnaeus, 1766)

The ring‐tailed coati (Nasua nasua) is a procyonid whose population is in sharp decline. Therefore, studies are needed to better understand the reproduction of this animal. For this reason, this study aimed to evaluate the morphology, morphometry and sperm ultrastructure of ring‐tailed coati sperm. Four captive adult males were used for this study. Slides stained with Bengal Rose were used for the morphometric and morphologic analyses. The length and width of the head were measured, as well as the length of the midpiece and tail and the total length of the sperm. Scanning electron microscopy and transmission electron microscopy were used for the ultrastructural analyses. The most obvious morphological abnormalities observed were coiled tails (6.1 ± 8.7%) and the lack of acrosomes (5.4 ± 4.4%). Regarding the morphometry, the measurements of the head (length × width), midpiece (length) and tail (length) were (mean ± SD) 6.2 ± 0.4 × 8.1 ± 0.6 μm, 14.1 ± 0.5 and 63.9 ± 4.1 μm, respectively, and the total length of the sperm was 86.1 ± 4.3 μm. Through electron microscopy, the presence of electron‐lucent points in the nucleus and the presence of approximately 55 mitochondrial spirals in the midpiece were identified. The data obtained in this study provide detailed information on the sperm characteristics of coatis and may inform future research on germplasm conservation, both for this species and other threatened procyonids.     

Grazing behaviour,physical activity and metabolic profile of two Holstein strains in an organic grazing system

The challenge for sustainable organic dairy farming is identification of cows that are well adapted to forage‐based production systems. Therefore, the aim of this study was to compare the grazing behaviour, physical activity and metabolic profile of two different Holstein strains kept in an organic grazing system without concentrate supplementation. Twelve Swiss (H_CH; 566 kg body weight (BW) and 12 New Zealand Holstein‐Friesian (H_NZ; 530 kg BW) cows in mid‐lactation were kept in a rotational grazing system. After an adaptation period, the milk yield, nutrient intake, physical activity and grazing behaviour were recorded for each cow for 7 days. On three consecutive days, blood was sampled at 07:00, 12:00 and 17:00 h from each cow by jugular vein puncture. Data were analysed using linear mixed models. No differences were found in milk yield, but milk fat (3.69 vs. 4.05%, P = 0.05) and milk protein percentage (2.92 vs. 3.20%, P < 0.01) were lower in H_CH than in H_NZ cows. Herbage intake did not differ between strains, but organic matter digestibility was greater (P = 0.01) in H_CH compared to H_NZ cows. The H_CH cows spent less (P = 0.04) time ruminating (439 vs. 469 min/day) and had a lower (P = 0.02) number of ruminating boli when compared to the H_NZ cows. The time spent eating and physical activity did not differ between strains. Concentrations of IGF‐1 and T3 were lower (P ≤ 0.05) in H_CH than H_NZ cows. In conclusion, H_CH cows were not able to increase dry matter intake in order to express their full genetic potential for milk production when kept in an organic grazing system without concentrate supplementation. On the other hand, H_NZ cows seem to compensate for the reduced nutrient availability better than H_CH cows but could not use that advantage for increased production efficiency.     

Death from anthropogenic causes is partially compensatory in recovering wolf populations

There is substantial interest in how mortality rates affect animal populations, but mechanisms explaining when and under what circumstances particular causes of death incur demographic responses are far from clear. In theory, small or expanding populations should experience additive mortality from anthropogenic causes of death, but whether such effects are homogenous across a population or expressed only in certain high-risk individuals is open for debate. We used competing risks models to analyze mortality patterns among radio-collared wolves (Canis lupus, n = 711) from three populations in northwestern United States (1982-2004), and evaluated the degree to which anthropogenic mortality was additive vs. compensatory to natural demographic processes. Almost 80% (n = 320) of wolves dying of known fates were killed by anthropogenic causes (legal control, illegal killing, harvest in Canada, vehicle collision), and additive effects of anthropogenic mortality were most pronounced in northwestern Montana where wolf exposure to humans and livestock was high compared to either the Greater Yellowstone Area or central Idaho, where anthropogenic risk was lower. In contrast, risk from natural hazards was lower in northwestern Montana than in the other areas, implying some degree of compensatory mortality from anthropogenic risk. Animals recruited to the study following human-wolf conflict had markedly higher anthropogenic risk than those recruited for standard monitoring purposes, and juvenile wolves as well as dispersers, succumbed to higher anthropogenic risk. Multivariate models revealed that increasing wolf population density promoted higher anthropogenic risk and reduced natural risk, indicating that partially-compensatory effects of anthropogenic mortality actually became increasingly additive with population density. The observed compensatory mortality and hazard heterogeneity in our study implies that demographic responses to mortality risk may be complex and more subtle than previously thought; the density-dependent effect of anthropogenic mortality portends a stabilizing influence of humans on recovering wolf populations. We conclude that future assessment of the role of anthropogenic mortality should include individual-based hazard estimation as a complement to traditional population-level approaches.     

Fungal growth on a common wood substrate across a tropical elevation gradient: Temperature sensitivity, community composition, and potential for above-ground decomposition

Fungal breakdown of plant material rich in lignin and cellulose (i.e. lignocellulose) is of central importance to terrestrial carbon (C) cycling due to the abundance of lignocellulose above and below-ground. Fungal growth on lignocellulose is particularly influential in tropical forests, as woody debris and plant litter contain between 50% and 75% lignocellulose by weight, and can account for 20% of the C stored in these ecosystems. In this study, we evaluated factors affecting fungal growth on a common wood substrate along a wet tropical elevation gradient in the Peruvian Andes. We had three objectives: 1) to determine the temperature sensitivity of fungal growth - i.e. Q₁₀, the factor by which fungal biomass increases given a 10 °C temperature increase; 2) to assess the potential for above-ground fungal colonization and growth on lignocellulose in a wet tropical forest; and 3) to characterize the community composition of fungal wood decomposers across the elevation gradient. We found that fungal growth had a Q₁₀ of 3.93 (95% CI of 2.76-5.61), indicating that fungal biomass accumulation on the wood substrate nearly quadrupled with a 10 °C increase in temperature. The Q₁₀ for fungal growth on wood at our site is higher than Q₁₀ values reported for litter decomposition in other tropical forests. Moreover, we found that above-ground fungal growth on the wood substrate ranged between 37% and 50% of that measured in the soil, suggesting above-ground breakdown of lignocellulose represents an unexplored component of the C cycle in wet tropical forests. Fungal community composition also changed significantly along the elevation gradient, and Ascomycota were the dominant wood decomposers at all elevations. Fungal richness did not change significantly with elevation, directly contrasting with diversity patterns observed for plant and animal taxa across this gradient. Significant variation in fungal community composition across the gradient suggests that the characteristics of fungal decomposer communities are, directly or indirectly, influenced by temperature.