An investigation of micronutrient supplementation in weaner lambs to improve growth rates in southeast Australia

OBJECTIVE

A producer survey by questionnaire assessed supplements used in sheep and reasons for use. This was followed by field trials on eight sheep properties in SE NSW to determine the effect of commonly used commercially available supplements on growth rates of Merino and crossbred lambs.

DESIGN

On each property, 450 lambs were selected at weaning and randomly allocated to nine groups of 50 sheep (eight treatment and a control group). Supplements were applied as per manufacturer's recommendation every 6-12 weeks. At each application, all sheep were weighed and data on general flock health and management were collected.

RESULTS

All but one of the survey respondents (n = 77) had used supplements in their sheep at some stage. The reasons for use were most commonly for general health and production benefits (n = 21; 26.9%) and to prevent or treat specific diseases/deficiencies (n = 7; 9.0%). The average daily weight gains (ADWG) of the lambs over the trial period varied from 0.074 kg to 0.213 kg/head/day. Statistical analysis showed that overall there was not a significant difference (P = 0.587) between ADWG among lambs that received supplements and lambs that did not.

CONCLUSION

Results of this study show that application of supplements were not linked to improved growth rates in clinically normal crossbred and Merino lambs under the trial farm conditions between weaning and 15 months of age. Effects of supplements on health and production in adult sheep and how supplement response can be best measured in sheep flocks (especially in relation to health and welfare) and linked to productivity requires further investigation.

A producer survey of knowledge and practises on gastrointestinal nematode control within the Australian goat industry

Gastrointestinal nematodes (GINs) have been identified in Australia as a major problem in goat production, with few anthelmintics registered for use in goats. Therefore, anecdotally many producers use anthelmintics that have not been registered for goats. Using unregistered products could increase selection pressure for anthelmintic resistance as well as safety and/or meat or milk chemical residues of products from treated goats. This producer survey was conducted in 2014 to establish Australian goat producer knowledge, perception and practises of GIN treatment and control. Eighty-eight producers responded to the survey. Of these respondents, 90% thought that GINs were a problem for the Australian goat industry, and 73% considered GINs had caused production losses or health impacts for their goats during the 5 years prior to the survey. With regard to anthelmintic resistance, 7% believed that anthelmintic resistance was not a problem at all, 93% acknowledged anthelmintic resistance was a problem in Australian goats herds, with 25% of these reporting their properties as being affected. The majority (81%) of respondents believed the number of anthelmintics registered for goats was inadequate for effective GIN control. Of the 85% of producers who used an anthelmintic during the survey period, 69% had used a treatment not registered for use in goats. Fifty respondents listed the anthelmintic dosage used, and 50% of those had used a dose rate greater than the recommended label dose. The average frequency of administration of anthelmintic was 2.5 times per annum. Of the 51% of respondents who listed the frequency of their treatments given during the survey period, 16% administered four or more treatments annually to the majority of their goats and 8% administered treatments on an "as needed" basis. Faecal egg count (FEC) had been performed on 72% of properties in at least one of the six years covered by the survey. These results indicated that the majority of surveyed producers use anthelmintics that are not registered for use in goats and at different dose rates to label. These practises have the potential for increasing the spread of anthelmintic resistance in the GIN populations of goats and sheep. Further, giving dose rates in excess of label recommendations could impact goat safety and/or product residues. Further research is needed to investigate these risks and evaluate more sustainable GIN control options for goat herds. In addition more effective dissemination of information is necessary for the improvement of the Australian goat industry.

Fasciola gigantica infection in large ruminants in northern Laos: smallholder knowledge and practices

High prevalence of Fasciola spp. infection in smallholder large ruminant farming systems has been confirmed in many regions of South-East Asia, yet information on trematode knowledge and any control practices of large ruminant farmers is lacking. We surveyed smallholder farmers (n = 326) in northern Laos on knowledge of liver fluke and its management in their large ruminants, identifying 93.1% of farmers had no knowledge and 6.9% minimal knowledge of the parasite and impacts on large ruminant production. The survey further confirmed anecdotal reports that control or prevention measures were lacking, with none of the surveyed producers using effective anthelminthic treatments or grazing strategies to control Fasciola spp. This was despite 20.6% of farmers having reported observing leaf-shaped parasites in the liver of their cattle or buffalo when slaughtered in the past. With increasing demand for red meat in the region, subsistence smallholder farmers are able to supply this market and increase their income. Athough the production impact of fascioliasis in large ruminants in these farming systems still needs to be quantified, farmer knowledge and control of fascioliasis in this region is likely to increase livestock productivity and improve rural livelihoods. This would help to address regional rural poverty and food insecurity, but requires improved knowledge to address the identified knowledge and practice gaps on presence, impact and control of fasciolosis. The majority (95.4%) of surveyed farmers indicated a desire to learn more about fascioliasis in large ruminants, suggesting that extension methods used in the past need adapting to result in more effective knowledge transfer and changed practices in future.

Progressing smallholder large-ruminant productivity to reduce rural poverty and address food security in upland northern Lao PDR

Applied participatory research on large-ruminant health and production was conducted in six villages in northern Lao PDR. Three villages were classified as ‘high intervention’ (HI) and the remaining three as ‘low intervention’ (LI) sites, with a suite of health and productivity interventions implemented in the HI sites enabling comparison of outcomes with the LI sites, where only a vaccination program was introduced. A 3-year longitudinal study to establish baseline production variables, including liveweight, average daily weight gain (ADG) and reproductive performance, was conducted. The study involved 1500 head of cattle and buffalo that were ear-tagged and weighed every 3–4 months between 2008 and 2011, producing 10 data-collection points. Significant differences in ADG of the cattle between the provinces (P < 0.001), but not between HI and LI villages (P = 0.39), was observed. Low calving rates (51–75% and 41–52%) and inter-calving intervals (13.6–15.7 and 18.6–20.6 months) for cattle and buffalo, respectively, were observed. An on-farm large ruminant-fattening trial (n = 44) was conducted over a 4-month period to examine differences in productivity between cut-and-carry stall fattening (n = 26) and free-grazing (n = 18) systems. Cattle and buffalo in fattening stalls (320 and 217 g/day) had significantly greater ADG than those free-grazing (40 and 85 g/day) (P < 0.001 and P = 0.001). The increase in sale value for fattened cattle and buffalo was US$78 and US$123, respectively. The longitudinal study indicated that if risks of important diseases such as foot and mouth disease and haemorrhagic septicaemia are controlled by vaccination and biosecurity, improved productivity outcomes in northern Lao PDR can be achieved by establishing forage plantations to better manage variations in seasonal availability of feed and enabling fattening. We conclude that improved large-ruminant productivity, by improving health and nutrition practices, offers opportunities for smallholder farmers to increase livestock income, alleviate rural poverty and improve regional food security in South-east Asia.

The impact of best practice health and husbandry interventions on smallholder cattle productivity in southern Cambodia

Future food security has become a major global concern and is particularly important in the Greater Mekong Subregion where several countries have seen rapid urban economic development and increasing demand for red meat. In Cambodia, the majority of livestock producers are subsistence or semi-subsistence rural smallholder farmers using cattle as a source of protein, fertiliser, draught power, and asset storage. Potential income from smallholder cattle is limited by a range of factors that compromise productivity, including endemic diseases, poor nutrition, and lack of knowledge of husbandry techniques and marketing practices. To address the developing opportunities to improve rural incomes from cattle production in Cambodia, a 4-year longitudinal study was conducted to examine ‘best practice’ interventions that could improve productivity and profitability of cattle within smallholder farming systems. The study involved six villages from three provinces, with two villages in each of the provinces of Takeo, Kandal and Kampong Cham paired and designated as either high intervention (HI) or low intervention (LI). A best practice intervention program was introduced to the HI villages to develop the husbandry skills of farmers, including implementation of forage technology, disease prevention through vaccination for foot-and-mouth disease and haemorrhagic septicaemia, deworming, and education in nutrition, biosecurity, disease control, and marketing. Between April 2008 and February 2012, eight repeat-measures capturing data on animal health and production, including cattle weights used to evaluate the impact of interventions on average daily gains, were completed. Cattle in HI villages had significantly (P < 0.01) higher mean liveweight during the last three sampling periods, and average daily gains were 2.4 times higher than in cattle of the LI villages. This study provides evidence that best practice interventions resulted in improved cattle productivity, farmer knowledge and positive impacts on household income over time, offering a pathway that can address food security concerns and more rapidly alleviate rural poverty in the GMS.

Improvement in smallholder farmer knowledge of cattle production, health and biosecurity in Southern Cambodia between 2008 and 2010

Farmer knowledge surveys were conducted in 2008 and 2010 in Cambodia to evaluate the impact of a research project studying interventions that can improve cattle production and health, including biosecurity and practices relating to risks of transmission of transboundary diseases. The project hypothesis is that by increasing the value of smallholder-owned large ruminants through nutritional interventions and improved marketing, knowledge-based interventions including risk management for infectious diseases such as foot-and-mouth disease (FMD) can be implemented into a more sustainable pathway for rural development. Between 2008 and 2010, significant improvements in farmer knowledge and attitudes were recorded in three villages in three provinces of southern Cambodia. This was achieved through participatory 'applied field research', 'on the job' training plus 'formal' training programmes. No cases of FMD were recorded during the study period in the 'high-intervention' (HI) villages despite the common occurrence of the disease in a nearby 'low-intervention' and many other villages in the three provinces. Whilst it is likely that protection of these villages from FMD infection was from increasing the herd immunity by vaccination, it could also have been partly because of a decrease in risk behaviours by farmers as a result of their increasing knowledge of biosecurity. The research indicates that smallholder farmers are motivated by nutritional interventions that improve the value of their cattle 'bank' and offer better marketing opportunities. This provides a more receptive environment for introduction of disease risk management for infectious and other production limiting diseases, best implemented for smallholder farmers in Cambodia by intensive training programmes. In lieu of a widespread public awareness programme to deliver mass education of smallholder farmers in disease prevention and biosecurity, livestock development projects in South-East Asia should be encouraged to include training in disease risk management as an important intervention if the current momentum for trade in large ruminant livestock and large ruminant meat is to continue to progress and contribute to addressing global food security concerns.

Longitudinal study of the spread of ovine Johne's disease in a sheep flock in southeastern New South Wales

OBJECTIVE

The aim of this study was to apply whole flock testing over time to determine the prevalence, distribution and spread of infection in a recently infected flock, with a view to planning intervention strategies for disease control.

PROCEDURE

Serology, pooled faecal culture (PFC) and histology were used to determine the distribution and persistence of infection in a sheep flock in south east New South Wales between 1997 and 2002. Partial flock testing was done up to June 2000, after which annual whole flock testing, using PFC was performed.

RESULTS

Faecal shedding of M a paratuberculosis was not detected in home-bred sheep until 7 years after the introduction of infected sheep in 1993. For at least 7 years there was clustering of infection and shedding within two age groups only. The infected groups appeared to have been exposed to infection (mycobacterial contamination) at an early age (<12 months) and commenced shedding at 5 years of age or older. Groups that were exposed to contamination as adults did not shed detectable amounts of M a paratuberculosis during the study period.

CONCLUSION

Clustering of detectable infection in age groups of sheep that were exposed as lambs was a feature on this farm, providing indirect evidence of finite duration of survival of M a paratuberculosis on pasture and the influence of age on the susceptibility of sheep to develop detectable M a paratuberculosis infection. Spread of infection occurred very slowly and was probably related to the long incubation period (exposure to shedding interval) of 5 years observed on this farm. The findings suggest that partial flock culling, selective grazing management and vaccination could lead to a reduction in mycobacterial contamination on farm to a level at which patent infection no longer occurs. Better understanding of disease spread within flocks over time through flock profiling using PFC will help in devising surveillance strategies (including testing protocols for market assurance testing) to detect infected flocks where there has been clustering and slow spread of infection.