Effects of intensification of pastoral farming on greenhouse gas emissions in New Zealand

Abstract

AIMS: The aims of this cross-sectional study were to investigate the herd and cow-level prevalence of bovine digital dermatitis (BDD) in dairy farms in the northern Taranaki region of New Zealand, and to identify whether there was any spatial clustering of herds with the disease.

METHODS: A survey of 224 dairy farms in the northern Taranaki region of New Zealand was undertaken from September 2014 to February 2015. Following training in robust criteria to confirm BDD visually, a technician inspected the rear feet of every milking cow on the farms during milking. The identity of cows with lesions and the feet involved were recorded. The proportion of cows affected among the inspected population (cow-level prevalence), the proportion of a herd affected (farm-level prevalence), and proportion of farms with ≥1 cow with lesions, were calculated. A bivariate K function analysis was then used to assess whether farms with ≥1 cow with lesions were clustered, after accounting for the distribution of the farms involved in the study.

RESULTS: Bovine digital dermatitis lesions were observed on 143/224 (63.8 (95% CI=57.5–70.1)%) farms. Within-farm prevalence was 0% on 81 (36.2%) farms, between >0 and <3% on 120 (53.5%) farms, with a maximum prevalence of 12.7% on one farm. Overall, cow-level prevalence was 707/60,455 (1.2 (95% CI=0.9–3.0)%), and on affected farms was 707/41,116 (1.7 (95% CI=1.4–2.1)%). In affected cows, 268/707 (37.9%) had a lesion on left foot only, 262/707 (37.1%) on the right foot only and 177/707 (25.0%) on both feet. The K function analysis showed no evidence of clustering of farms with BDD.

CONCLUSIONS: Bovine digital dermatitis was widespread among the survey farms, but there was no evidence that there was any clustering of herds with BDD. The cow-level prevalence on affected farms was much lower than reported elsewhere.

CLINICAL RELEVANCE: Although the prevalence at the cow level was low, if these data are representative of other regions of New Zealand, BDD could easily become a major problem on dairy farms in New Zealand, as has been observed in other countries.     

Feeding value of pastures for horses

The feeding value of fresh pasture grazed in situ is determined by animal performance or productivity and could be relatively easily established for growing and lactating horses. Despite this, there is a lack of published information on the relative feeding value of different pastures and forages grazed by horses in New Zealand and the world. In addition, for adult breeding or non-breeding and young or adult sport or performance horses, the definition of feeding value and its determination remain problematic.

Limited information suggests that the feeding value of perennial ryegrass-based pasture in New Zealand for young growing horses is high, and growth rates for Thoroughbred horses fed solely on pasture in New Zealand are similar to those reported from the Northern Hemisphere where grain-based supplements are fed in addition to pasture or other forages. Attempts to assess the ability of fresh pastures to meet the nutrient requirements of horses are hampered by problems associated with determination of feed intake by grazing horses and lack of knowledge of the digestibility and utilisation of digested nutrients, including the relative bio availability of macro- and micro-minerals in pasture. A further challenge for future research is to determine the effect of herbage allowance and grazing behaviour, including pasture species preferences, on voluntary feed intake by grazing horses.

Grazing pasture has benefits for equine health and well-being including reduced risk of some nutrition-related disorders and reduced prevalence of stereotypic behaviour. Pastured horses have greater freedom for expression of natural behaviours including social interaction and exercise. However, grazing pasture is also associated with animal health problems, particularly parasitism and diseases related to pasture-associated toxins.     

Impact of harvest year on amino acids and sugars in potatoes and effect on acrylamide formation during frying

Acrylamide is formed via the Maillard reaction between reducing sugars and asparagine in a number of carbohydrate-rich foods during heat treatment. High acrylamide levels have been found in potato products processed at high temperatures. To examine the impact of harvest year, information on weather conditions during growth, that is, temperature, precipitation, and light, was collected, together with analytical data on the concentrations of free amino acids and sugars in five potato clones and acrylamide contents in potato chips (commonly known as crisps in Europe). The study was conducted for 3 years (2004-2006). The contents of acrylamide precursors differed between the clones and the three harvest years; the levels of glucose were up to 4.2 times higher in 2006 than in 2004 and 2005, and the levels of fructose were 5.6 times higher, whereas the levels of asparagine varied to different extents. The high levels of sugars in 2006 were probably due to the extreme weather conditions during the growing season, and this was also reflected in acrylamide content that was approximately twice as high as in preceding years. The results indicate that acrylamide formation is dependent not only on the content and relative amounts of sugars and amino acids but also on other factors, for example, the food matrix, which may influence the availability of the reactants to participate in the Maillard reaction.     

Foraging strategies of the external mycelium of the arbuscular mycorrhizal fungi Glomus intraradices and Scutellospora calospora

The responsiveness of the external mycelium of Glomus intraradices and Scutellospora calospora was tested in a multiple-choice experimental system in which mycelium encountered patches amended with nitrogen (N) or phosphorus (P), either alone or in combination with a host plant. We hypothesised that only AMF mycelium with sufficient supply of photosynthate from an actively growing host would respond to the amendments provided. Mycelium was allowed to grow either 11 or 21 weeks before we analysed hyphal proliferation in amended patches introduced in mesh bags that were not reached by roots but by foraging mycelium only. Hyphal length, the AMF signature fatty acid 16:1w5, and root colonisation in new host plant seedlings were used to measure AMF growth and resource allocation in the patches. Mycelium from both fungal strains was able to colonise new host roots and sand in all patches but S. calospora was overall more responsive to the amendments than G. intraradices. G. intraradices grew equally into all patches, including the unamended control, whereas S. calospora produced significantly more hyphal length in the patch containing a host plant than in the rest of the patches. Both strains showed lower hyphal growth at the second harvest and mycelium of G. intraradices lost almost entirely its capacity to develop new mycelium in all choices presented. Lipid measurements showed this fungus did not use storage lipids to exploit the patches. S. calospora mycelium had reduced growth and colonisation ability but still showed some growth in the patches at the second harvest. A reduction in the content of NLFA 16:1w5 from the first to the second harvest suggested that S. calospora mycelium likely used storage lipids to sustain proliferation in the patches. The results indicated that S. calospora was more active and used more resources for foraging than G. intraradices and that external mycelium foraging was maintained mainly with recently acquired plant carbon (C). This supported in general our hypothesis but showed as well that the two AMF strains had different strategies and resource allocation to forage. The overall low response of both AMF to the choices presented suggested that the responsiveness of mycelium searching freely in the substrate is lower than that observed in experimental systems in which the amendments have been placed in close contact with actively growing mycelium fronts in close vicinity with host roots.     

Identification of nine sequence types of the 16S rRNA genes of Campylobacter jejuni subsp. jejuni isolated from broilers

Background

Campylobacter is the most commonly reported bacterial cause of enteritis in humans in the EU Member States and other industrialized countries. One significant source of infection is broilers and consumption of undercooked broiler meat. Campylobacter jejuni is the Campylobacter sp. predominantly found in infected humans and colonized broilers. Sequence analysis of the 16S rRNA gene is very useful for identification of bacteria to genus and species level. The objectives in this study were to determine the degree of intraspecific variation in the 16S rRNA genes of C. jejuni and C. coli and to determine whether the 16S rRNA sequence types correlated with genotypes generated by PFGE analysis of SmaI restricted genomic DNA of the strains.

Methods

The 16S rRNA genes of 45 strains of C. jejuni and two C. coli strains isolated from broilers were sequenced and compared with 16S rRNA sequences retrieved from the Ribosomal Database Project or GenBank. The strains were also genotyped by PFGE after digestion with SmaI.

Results

Sequence analyses of the 16S rRNA genes revealed nine sequence types of the Campylobacter strains and the similarities between the different sequence types were in the range 99.6–99.9%. The number of nucleotide substitutions varied between one and six among the nine 16S rRNA sequence types. One of the nine 16S rRNA sequence profiles was common to 12 of the strains from our study and two of these were identified as Campylobacter coli by PCR/REA. The other 10 strains were identified as Campylobacter jejuni. Five of the nine sequence types were also found among the Campylobacter sequences deposited in GenBank. The three 16S rRNA genes in the analysed strains were identical within each individual strain for all 47 strains.

Conclusion

C. jejuni and C. coli seem to lack polymorphisms in their 16S rRNA gene, but phylogenetic analysis based on 16S rRNA sequences was not always sufficient for differentiation between C. jejuni and C. coli. The strains were grouped in two major clusters according to 16S rRNA, one cluster with only C. jejuni and the other with both C. jejuni and C. coli. Genotyping of the 47 strains by PFGE after digestion with SmaI resulted in 22 subtypes. A potential correlation was found between the SmaI profiles and the 16S rRNA sequences, as a certain SmaI type only appeared in one of the two major phylogenetic groups.     

Effect of restricted suckling on milk yield,milk composition and udder health in cows and behaviour and weight gain in calves,in dual-purpose cattle in the tropics

The study was conducted to evaluate the effects of restricted suckling (RS) in dual-purpose cows and calves compared to artificial rearing (AR). Twelve Holstein-Zebu cows with calves were assigned to each treatment. Cows were milked once daily in the morning with calves present to stimulate milk let-down. RS calves suckled 30 min after milking and 30 min in the afternoon, whereas AR calves were milk-fed from nipple bottles. The daily saleable milk yield was higher in RS than in AR cows (p < 0.01; 7.44 vs 6.50 kg/day), whereas RS cows had lower milk-fat content (p < 0.001). AR cows had higher California Mastitis Test scores (p < 0.001) and lower lactose content (p < 0.001) compared to RS cows, which indicates an improved udder health in RS cows. AR calves displayed more ‘cross-suck’ during suckling/milk feeding (p < 0.001) and during observations of general behaviour (p < 0.05), and more ‘lick and sniff interior’ during milking (p < 0.05) and suckling/milk feeding (p < 0.01), compared to RS calves. During observations of general behaviour the RS calves were more often observed to ‘walk’ (p < 0.01) and ‘lick self’ (p < 0.05) and less frequently to ‘eat concentrate’ (p < 0.05) than AR calves. Results support the hypothesis that RS increases milk yield, influences milk composition and improves udder health in cows, and decreases abnormal sucking in calves.     

Hunting behavior of a marine mammal beneath the antarctic fast Ice

The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder. Weddell seals stalked large Antarctic cod and the smaller subice fish Pagothenia borchgrevinki, often with the under-ice surface for backlighting, which implies that vision is important for hunting. They approached to within centimeters of cod without startling the fish. Seals flushed P. borchgrevinki by blowing air into subice crevices or pursued them into the platelet ice. These observations highlight the broad range of insights that are possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.     

The role of the environment in partial migration: food availability affects the adoption of a migratory tactic in brown trout Salmo trutta

Abstract –  Alternative reproductive tactics are commonly reported for salmonids (Pisces) and typically involve large migratory and small resident individuals. Variation in migratory tendency should reflect the different benefits and costs that the two different phenotypes face with regard to fitness. Therefore, the effect of food availability on the adoption of a migratory tactic in brown trout was investigated. Fifty trout were placed in each of 12 tanks and fed at three different levels. Growth-related variables were measured regularly, and at the end of the experiment, the proportion of migrants and residents was recorded. Low food availability led to increased numbers of migratory fish. The expected sex-bias was also present, with a lower percentage of resident females than resident males. As all fish originated from the same gene pool, the changing proportions of the migratory tactics can be classified as phenotypic plasticity. The study provides evidence that the different phenotypes reflect alternative tactics within a conditional strategy. Some differences in growth-related variables were present between the sexes, and a very pronounced difference in condition factor was found between resident and migratory males, but not in females. Thus, the results provide evidence that different selective forces may be acting on the sexes.     

Evolutionary analysis of plant jacalin-related lectins (JRLs) family and expression of rice JRLs in response to Magnaporthe oryzae

Jacalin-related lectins (JRLs) are widely distributed carbohydrate-binding proteins in the plant kingdom, which play key roles in development and pathogen defense. In this study, we profiled evolutionary trajectory of JRLs family in 30 plant species and identified domain diversification and recombination leading to different responsive patterns of JRLs in rice during defense against rice blast. All of 30 plant species analyzed in our study have two types of JRLs by containing either a single jacalin or repeated jacalin domains, while chimeric jacalins exist in more than half of the species, especially in the Poaceae family. Moreover, Poaceae species have evolved two types of unique chimeric JRLs by fusing the jacalin domain(s) with dirigent or NB_ARC domain, some of which positively regulate plant immunity. Seven Poaceae-specific JRLs are found in the rice genome. We further found expression of rice JRLs, including four Poaceae-specific JRLs, are induced by Magnaporthe oryzae infections at either early or late infection stages. Overall, the results present the evolutionary trajectory of JRLs in plant and highlight essential roles of Poaceae specific JRLs against pathogen attacks in rice.     

Zoospore chemotaxis of closely related legume‐root infecting Phytophthora species towards host isoflavones

Phytophthora niederhauserii, P. pisi, P. sojae and P. vignae are closely related species that are pathogenic to various legume plants. While P. sojae and P. vignae are reported to specifically infect soybean and cowpea, respectively, P. pisi is reported to attack pea and faba bean. Phytophthora niederhauserii is considered to have a broad host range. Zoospores of some Phytophthora species are chemotactically attracted to the isoflavones that are secreted by their host plants. The focus of the current study was to determine the chemotaxic behaviour of zoospores from closely related legume‐root infecting Phytophthora species and to investigate the correlation, if any, to host preference as determined by greenhouse pathogenicity tests. The results showed that P. sojae and P. vignae were attracted to the non‐soybean isoflavone prunetin as well as to the soybean isoflavones genistein and daidzein, which is in contrast with their host specificity on soybean and cowpea, respectively. On the other hand, P. pisi and P. niederhauserii were only attracted to prunetin, previously reported to be produced by pea, but not to the isoflavones associated with the non‐host soybean. The lack of responsiveness to genistein and daidzein in P. pisi may represent a recent adaptation to the host specialization towards pea. However, the affinity of P. niederhauserii to prunetin shows that this trait can also be present in taxa not specifically associated with legume hosts.