Drivers,challenges and opportunities of forage technology adoption by smallholder cattle households in Cambodia

Forage technology has been successfully introduced into smallholder cattle systems in Cambodia as an alternative feed source to the traditional rice straw and native pastures, improving animal nutrition and reducing labour requirements of feeding cattle. Previous research has highlighted the positive impacts of forage technology including improved growth rates of cattle and household time savings. However, further research is required to understand the drivers, challenges and opportunities of forage technology for smallholder cattle households in Cambodia to facilitate widespread adoption and identify areas for further improvement. A survey of forage-growing households (n = 40) in July–September 2016 examined forage technology adoption experiences, including reasons for forage establishment, use of inputs and labour requirements of forage plot maintenance and use of forages (feeding, fattening, sale of grass or seedlings and silage). Time savings was reported as the main driver of forage adoption with household members spending approximately 1 h per day maintaining forages and feeding it to cattle. Water availability was reported as the main challenge to this activity. A small number of households also reported lack of labour, lack of fencing, competition from natural grasses, cost of irrigation and lack of experience as challenges to forage growing. Cattle fattening and sale of cut forage grass and seedlings was not found to be a widespread activity by interviewed households, with 25 and 10% of households reporting use of forages for these activities, respectively. Currently, opportunities exist for these households to better utilise forages through expansion of forage plots and cattle activities, although assistance is required to support these households in addressing current constraints, particularly availability of water, if the sustainability of this feed technology for smallholder cattle household is to be established in Cambodia.     

The relative sensitivity to plant water stress during the reproductive phase of upland cotton (Gossypium hirsutum L.)

Summary The relative sensitivity of the cotton plant to water stress throughout the growing season was determined to identify when irrigation will have the greatest beneficial effect. Daily plant water stress for 72 different data sets of water applications was correlated to corresponding yield criteria. The magnitude of significant correlation was interpreted as the degree of sensitivity. Plant water stress during square formation and early flowering resulted in fewer bolls to reach maturity, but this detrimental effect was cancelled by the development of bigger bolls due to greater lint growth. This resulted in better seedcotton and lint yields. Flower and boll senescence which resulted from water stress during flowering peak, however, inhibited seedcotton and lint yields. The most pronounced inhibiting effect stress had on yields, was during boll development well after the end of effective flowering, when it inhibited boll development. Stress during ripening of the bolls increased lint and boll development and consequently enhanced yields. When limited quantities of water is available, preference should be given to irrigation during boll development, then by irrigation when the first flowers appear, followed by irrigation during peak flowering. Water should be withheld from opening of the first bolls.     

Leptin, GH, PRL, Insulin and Metabolic Parameters Throughout the Dry Period and Lactation in Dairy Cows

Leptin may play a role in the endocrine-metabolic processes that guarantee the physiological course of lactation in dairy cattle. This study was aimed at determining the changes in plasma concentrations of leptin and some of the main hormones and metabolites involved in the lactogenetic process in high-yielding dairy cows throughout lactation; we also wanted to assess whether leptin secretion is subjected to seasonal influences. Blood samples were collected from 23 Italian Friesian dairy cows from the end of a lactation to the ninth month of the subsequent one; in addition, blood was sampled from 47 dairy cows in different phases of lactation during February and July. Plasma concentrations of leptin, growth hormone (GH), insulin, prolactin (PRL), glucose, non-esterified fatty acids (NEFA) and urea were quantified by either validated radioimmunoassay (RIA) or enzymatic colorimetric methods. At the beginning of lactation, GH concentrations significantly increased, while a significant reduction occurred in leptin and insulin. This endocrine condition, such as the significant increase in NEFA plasma concentrations, is indicative of a marked lipid mobilization. In the more advanced stages of lactation, when both energy and protein balances become positive, leptin plasma concentrations increased, whereas GH and NEFA concentrations declined. During the summer months, a significant increase in leptin plasma concentrations, irrespective of the phase of lactation, was observed. Collectively, our findings suggest that, in dairy cows, leptin may represent a 'metabolic signal' of animal's status of fattening and nutritional level; in addition, leptin seems to be influenced by photoperiod and environmental temperature.     

The Control of Rinderpest in Tanzania between 1997 and 1998

In January 1997, Tanzania requested international assistance against rinderpest on the grounds that the virus had probably entered the country from southern Kenya. Over the next few months, a variety of attempts were made to determine the extent of the incursion by searching for serological and clinical evidence of the whereabouts of the virus. At the clinical level, these attempts were hampered by the low virulence of the strain, and at the serological level by the lack of a baseline against which contemporary interpretations could be made. Once it became apparent that neither surveillance tool was likely to produce a rapid result, an infected area was declared on common-sense grounds and emergency vaccination was initiated. The vaccination programme had two objectives, firstly to prevent any further entry across the international border, and secondly to contain and if possible eliminate rinderpest from those districts into which it had already entered. On the few occasions that clinical rinderpest was subsequently found, it was always within this provisional infected area. Emergency vaccination campaigns within the infected area ran from January to the end of March 1997 but were halted by the onset of the long rains. At this time, seromonitoring in two districts showed that viral persistence was still theoretically possible and therefore a second round of emergency vaccination was immediately organized. Further seromonitoring then indicated a large number of villages with population antibody prevalences of over 85%. These populations were considered to have been `immunosterilized'. Although no clinical disease had been observed in them, it was decided to undertake additional vaccination in a group of districts to the south of the infected area. Serosurveillance indicated that rinderpest could have been present in a number of these districts prior to vaccination. Serosurveillance in 1998 suggested that numerous vaccinated animals had probably moved into districts outside the infected and additional vaccination areas, but did not rule out the continued presence of field infection.     

Dirofilaria repens in a cat with acute liver failure

Acute liver failure was diagnosed in a 12-year-old cat. Fine needle aspirate cytology revealed high numbers of unsheathed microfilariae and a hepatocellular reaction with no evidence of bacterial infection. The microfilariae were identified as those of Dirofilaria repens by acid phosphatase staining. The high number of microfilariae seen in both the blood and the liver aspirate samples as well as the favourable response to ivermectin amongst other drugs administered, is suggestive that D. repens was the cause of the liver insult. A positive result obtained with an antigen-capture ELISA (Dirochek) for Dirofilaria immitis antigen was interpreted as false. This is the 1st report of Dirofilaria repens for South Africa.     

Transport of nutrients and electrolytes across the intestinal wall in pigs

In recent years, intestinal transport processes have been studied in detail regarding both, functional and structural aspects. For monosaccharides different systems have been demonstrated for apical uptake: this includes the high-affinity SGLT1 as a distinct d-glucose system and GLUT5 for fructose. Specifically in pigs a low affinity, high-capacity system for d-glucose and d-mannose with no preference for Na⁺ over K⁺ and a very low affinity system are suggested as further uptake systems. As in other species, basolateral extrusion is mediated by GLUT2. The distributions of monosaccharide transport along the gastrointestinal axis as well as the potential role of paracellular monosaccharide absorption have not yet been clarified.

Amino acids can principally be absorbed by the paracellular and transcellular pathway whereas transcellular transport can either be mediated by facilitated diffusion or secondary active Na⁺-coupled transport. This includes different transport systems for neutral, anionic and cationic acids. In addition, the presence of the di-/tripeptides transport system PEPT1 which depends on an inwardly directed H⁺-gradient has also been confirmed for the pig small intestine, its quantitative proportion is still under debate.

Short chain fatty acids (SCFA) are the major end products of microbial carbohydrate fermentation which occurs along the gastrointestinal tract with the highest production rates in the large intestines. At least two uptake mechanisms have to be assumed, i.e., non-ionic diffusion and anionic exchange via SCFA⁻/HCO₃⁻-exchange. Controversial views still exist to what extent SCFA are metabolized within the epithelial tissue.

Segmental differences between small and large intestines have been demonstrated for Na⁺ absorption. Whereas in the small intestines the major part of Na⁺ absorption is mediated by coupled nutrient transport systems, aldosterone sensitive Na⁺ channels and Na⁺/H⁺-exchange are the dominant mechanisms in the hindgut. For Cl⁻ paracellular transport and anionic Cl⁻/HCO₃⁻-exchange are the major absorptive mechanisms. Cl⁻ secretion is mediated by apical channels which may be activated by toxins of different origin. Different types of Cl⁻ channels have been identified, such as Cystic Fibrosis Transmembrane Regulator (CFTR), Ca-activated Cl⁻ channels (CLCA) and Outwardly Rectifying Cl⁻ Channels (ORCC). Whereas CFTR has clearly been shown for jejunal and colonic epithelial and goblet cells controversy still exists on the relevance of CLCA and ORCC in pigs.

For Ca²⁺ there is evidence that both recently published channels TRPV5 and TRPV6 are also expressed in pig intestinal tissues, however, this has not yet been shown on protein level. From several functional approaches it was demonstrated that phosphate uptake can be mediated by both, a Na⁺-dependent transcellular component and paracellularly. On a molecular basis it is uncertain whether the transport protein of transcellular mechanism belongs to the NaPi-IIb cotransporter family.