Can fenbendazole-medicated molasses blocks control Toxocara vitulorum in smallholder cattle and buffalo calves in developing countries? Studies from upland Lao PDR
Context. Anthelmintic treatments are not widely adopted by smallholder farmers in Laos (Lao People’s Democratic Republic) to treat bovid Toxocara vitulorum, resulting in high calf morbidity and mortality.
Aims. Field trials were conducted to provide baseline efficacy data on an alternative, easy-to-use treatment by provision of fenbendazole-medicated molasses blocks (FMB) in situ.
Methods. Participating villages were randomly allocated to the following treatments: (1) conventional orally administered pyrantel, (2) access to FMB, (3) access to non-medicated molasses blocks (MB), and (4) no blocks (control). Faecal eggs per gram (EPG) and weight were monitored in cattle (n = 171) and buffalo calves (n = 44) under field conditions for 48–56 days.
Key results. In 2016, the MB treatment was associated with the fastest reduction in predicted average EPG at 2% per day, while FMB and pyrantel had an equivalent reduction of 1% per day, relative to the control (P = 0.062). Predicted average weight also differed significantly among treatments, with pyrantel and MB having the greatest average daily gain at 230 g and FMB at 200 g, which was higher than for control calves at 170 g (P = 0.002). In buffalo calves, treatment was not significantly associated with EPG or weight. The 2018 trial corroborated that FMB and MB treatments were associated with increased EPG reductions in cattle at 3% per day, relative to control calves (P = 0.007). Again, the MB treatment had the greatest predicted average daily gain at 200 g, compared with FMB calves at 160 g and control calves at 150 g (P = 0.005).
Conclusions. The field trials provided baseline evidence that FMB and MB have potential applications in reducing environmental contamination of T. vitulorum eggs and may improve calf growth in low-input systems. However, further testing ex situ is required to control for variability in calf weight and T. vitulorum burdens, so as to optimise anthelmintic doses, assess the addition of urea to the block formula and assess product marketability.
Implications. If successful, medicated nutrient blocks may be a simple method to reduce calf mortality and morbidity, enhancing the reproductive efficiency of large ruminant production in smallholder farms in developing countries.
Investigation of smallholder farmer biosecurity and implications for sustainable foot-and-mouth disease control in Cambodia
In Cambodia, the majority of the population is rural and reliant on subsistence agriculture, with cattle raised by smallholder farmers using traditional practices, resulting in low productivity and vulnerability to foot-and-mouth disease (FMD). As FMD causes deleterious impacts on rural livelihoods, known FMD risk factors were reviewed, using knowledge, attitudes and practice (KAP) surveys of smallholders(n=240) from four regions. The study aimed to understand current biosecurity threats to smallholder livelihoods and investigate the hypothesis that small holder farmers practising FMD risk management should be associated with higher incomes from cattle. Descriptive data were examined to demonstrate trends in KAP and a multivariable linear regression model developed to identify cattle income predictors. Results showed that baseline mean knowledge scores were low at 28.4% across all regions and basic biosecurity practices, including quarantine of new cattle, isolation of sick cattle and FMD vaccination, were lacking. As farmers purchase and sell cattle from and to various administration levels (including export), there is high risk of FMD transmission into and from smallholder communities. The final multivariable linear regression model identified significant explanatory parameters for annual cattle income, including region, number of calves born, forage plot size (ha), vaccination of cattle and the number of cattle purchased (F pr.<0.001,R2=29.9). Individual biosecurity practices including FMD vaccination were not significant predictors of income. With the current focus of farmers on treatment of FMD with inappropriate antibiotics leading to potential anti-microbial residue issues, yet receptivity to payment for vaccine in most regions, there is an urgent need for a coordinated national biosecurity and FMD management public awareness campaign. Further, to enhance the association between improved cattle health and rural livelihoods, it is recommended that livestock development programmes implement a systems approach to enhance farmer KAP in biosecurity, nutrition, reproduction and marketing of cattle.
An investigation of interventions associated with improved cattle and buffalo reproductive performance and farmer knowledge on smallholder farms in Lao PDR
Context. Smallholder beef farming in Lao People’s Democratic Republic (Laos) is constrained by poor reproductive performance, contributing to regional food insecurity. To address this, interventions were promoted in some rural communities by extension services to enhance cattle and buffalo nutrition, health, and reproductive husbandry.
Aims. This study assessed the impacts of these interventions on cattle and buffalo reproductive performance.
Methods. Knowledge, attitude and practice surveys were conducted on smallholder beef farmers in 2015 (n = 637) and 2018 (n = 226). With written records lacking on these farms, the survey relied on farmer recall of the number of calves born in the previous 12 months and the number of female cows (>12 months of age) present. The rate of these, calves/female cows, was used as an indicator of reproductive performance.
Key results. This proportion was higher in 2018 at a predicted mean 0.27 calves/cow compared with 2015 at 0.21 calves/cow (P < 0.001), suggesting a beneficial effect of interventions over time. Specifically, reproductive performance improved with increasing land dedicated to forages (P < 0.001) and increased farmer market-orientation (P = 0.006). Farmers who believed that selling sick large ruminants stopped the spread of disease had enhanced reproductive performance (P = 0.008). Although the practice of culling animals of low reproductive performance is desirable, in countries where foot-and-mouth disease is endemic, it is important to discourage practices that increase infectious disease transmission risk.
Conclusion. As reproductive knowledge interventions were not associated with reproductive performance, introducing interventions such as castration and weaning to consolidate reproductive knowledge is recommended as well as addressing challenges that limit forage adoption; and debunking misconceptions on effectiveness of biosecurity.
Implications. The use of evidence-based research helps inform the selection of interventions required to best enhance reproductive efficiency, potentially leading to improved reproductive performance of smallholder large ruminant systems in Laos and beyond.
Improving smallholder cattle reproductive efficiency in Cambodia to address expanding regional beef demand
This study aimed to identify factors associated with cattle reproductive output in rural smallholder farms in Cambodia in order to determine the main causes of reproductive failure and design efficient interventions for improvement. The majority of the nation’s beef is produced on smallholder farms where productivity is constrained by poor animal reproductivity reflected in the recent livestock population decline of approximately 13 % from 2009 to 2013. Farmers (n = 240) from 16 villages from five provinces were surveyed in mid-2015 to determine their baseline knowledge, attitude and practices (KAP) associated with cattle reproduction. In addition, 16 case studies from three of these provinces were conducted to provide a more detailed assessment of current cattle reproductive husbandry practices. In order to assess the reproductive impact of previously implemented interventions, an endpoint KAP survey and longitudinal health and husbandry study from three Cambodian provinces conducted between 2008 and 2013 were also analysed. Three multivariable prediction models (two KAP and one longitudinal) identified the following significant factors associated with the reproductive outcomes ‘number of calves born’ or probability that cows ‘gave birth’: target feeding (P = 0.074), growing vegetables (P = 0.005), attitudes towards cattle vaccination (P = 0.010), improving bull selection (P = 0.032), local breed use (P = 0.005), number of joining attempts (PP = 0.003) and retention of breeding animals (P < 0.001). The identification of significant factors and interventions in this study has led to intervention recommendations that can potentially improve reproductive efficiency, combat the declining cattle population and improve smallholder capacity to supply to expanding regional meat demand in South-East Asia and China.
Investigation of infectious reproductive pathogens of large ruminants: Are neosporosis, brucellosis, leptospirosis and BVDV of relevance in Lao PDR?
N. caninum, bovine viral diarrhoea virus, Brucella abortus and Leptospira interrogans serovar Hardjo are globally significant reproductive pathogens that cause abortion and reproductive loss in large ruminants. Prevalence information is lacking in Lao People's Democratic Republic (Laos) despite the poor reproductive performance of cattle and buffalo. Serological examination of frozen cattle (n = 90) and buffalo (n = 61) sera by commercially available enzyme-linked immunosorbent assays provided the first reported screening of some of these pathogens in Laos. Seroprevalence differed amongst these large ruminant species, with N. caninum, BVDV and L. interrogans serovar Hardjo antibodies found in 68.9% (95% CI ± 11.6), 4.9% (95% CI ± 5.4) and 3.3% (95% CI ± 4.5) of buffalo sera, respectively, and in 7.8% (95% CI ± 5.5), 10.0% (95% CI ± 6.2) and 22.2% (95% CI ± 8.6) of cattle sera, respectively. Buffalo sera had a significantly higher seroprevalence of N. caninum compared to cattle (p < 0.001) and cattle sera had a significantly higher seroprevalence of L. interrogans serovar Hardjo compared to buffalo (p = 0.003). Variability was also observed across provinces for N. caninum in buffalo (p = 0.007) and for L. interrogans serovar Hardjo in cattle (p = 0.071), suggesting provincial risk factors conducive to pathogen transmission. BVDV and N. caninum seropositivity were negatively associated in buffalo (p = 0.018) and cattle (p = 0.003). In buffalo, L. interrogans serovar Hardjo and BVDV seropositivity were associated (p = 0.035, p = 0.039). The identification of antibodies against three major abortifacient pathogens in Laos prompts further research to determine if infection is associated with low reproductive efficiency and the risk factors for infection. This is needed for the development of evidence based prevention strategies for improved large ruminant reproductive management among smallholders in Laos.
Provision of urea–molasses blocks to improve smallholder cattle weight gain during the late dry season in tropical developing countries: studies from Lao PDR
Context. Large-ruminant production in developing countries is inefficient with low growth rates and declining weights, particularly in the dry season.
Aims.The impact of ad libitum supplementation of cattle with high-quality molasses blocks (20 kg) containing either 8% urea (UMB) or nil urea (MB), was examined.
Methods. Field trials on smallholder farms compared weight changes and average daily gains (ADG = g/day) data of young calves <8 months of age (n = 25)" growing calves 8–24 months (n = 35) and lactating cows (n = 46), of the indigenous breed when accessing either UMB or MB, with data being collected at Weeks 1, 4, 8 and 12. A pen study was also conducted at a research station involving mature, lactating crossbred cows (n = 37). Surveys of farming families experiencing use of the blocks was conducted (n = 20).
Key results. On smallholder farms, animals accessing UMBs were heavier than those accessing MBs at every collection day and in young calves these differences were statistically significant (P < 0.05). ADGs were higher in cattle accessing UMB than in those accessing MBs. Young calves had the highest ADG (251–265 g/day), followed by growing calves (198–237 g/day) and lactating cows (187–190 g/day), although differences in ADG between UMB and MB cohorts were not considered significant (young calves P = 0.562" growing calves P = 0.509" and lactating cows P = 0.993). Results from the pen study identified that ADGs were not significantly different (P = 0.933) between crossbred cows accessing MBs (236 g/day) and cows accessing UMBs (229 g/day). Surveys of farmers using blocks confirmed that their animals were calmer and healthier, and had better coat condition with minimal external parasites" these farmers wished to purchase the blocks and were willing to pay a mean up to US$6.5 ± 2.3 per block.
Conclusions. Provision of UMBs and MBs in Laos in the late dry season improved cattle growth rates, which is consistent with previous studies and far superior to the base-line data from Laos demonstrating declining ADGs. Farmers considered that the blocks contributed greatly to herd management and improved sale-ability of their cattle.
Implications. Provision of molasses blocks on low-input smallholder farms in developing countries significantly improves production efficiency, offering an 'entry point' intervention while forages are becoming established.