Dairy & Veterinary Sciences - Juniper Publishers
Abstract
A cross-sectional survey was performed in 98 smallholder (SH) goat producers from the arid canyons and Valleys of northwestern Argentina, with the aim of describing infectious and parasitic disease occurrence in dairy goat flocks. SH were subjected to an ad hoc survey to gather data on flock management. On average 23 goat per SH flock were blood and fecal matter sampled. Serum were processed to diagnose brucellosis, paratuberculosis, caprine arthritis-encephalitis virus (CAEV), chlamydiosis, toxoplasmosis, leptospirosis, caprine herpesvirus 1 (CpHV-1) and neosporosis. Fecal samples were taken for helminth eggs counts per gram (epg) and coprocultures. Mean annual mortality rate per flock was 16.7±9.1%. Mean abortion and still births occurrence (9.6 ±8.1) recorded within the flocks, was associated to retained placenta (42.9%). Clinical mastitis-associated problems were recorded in 83.6% of SH flocks. The mean morbidity and mortality rate of clinical mastitis was respectively 6.9±6.5 % and 1.6±1.5 %. Contagious echtyma was detected in 70.4% of the SH flocks. Caprine seroprevalence of brucellosis, leptospirosis, paratuberculosis, toxoplasmosis, clhamydiosis, CpHV-1, CAEV and neosporosis was 0.04%, 4.03%, 7.8%, 21.9%, 18.7%, 29.5%, 10.7% and 42.7% respectively. Lice (Linognathus spp.) were a kid problem for 87% SH flocks. Mean epg, according arid or semiarid region was respectively 182 and 1037. Haemonchus and Trichostrongylus and secondly Teladorsagia were the prevailing nematode genera. Caprine prevalence of Fasciola hepatica in feces was 51.6%. The presence of hydatid cysts in slaughtered animals were indicated by 48.2% of SH. These results provide an indication of the possible impact of the reported diseases on goat production and SH health and welfare.
Keywords: Smallholder; Dairy goat; Infectious diseases; Parasitic diseases; Argentina´s northwest
Abbreviations: SH: Smallholder; CAEV: Caprine arthritis-encephalitis virus; CpHV-1: Caprine herpesvirus 1; epg: Helminth egg counts per gram
Introduction
In the arid and valleys canyons of Salta and Jujuy provinces of Northwestern Argentina the extensive production of goat milk and meat is an activity that is mostly of smallholder (SH) hands who manage a subsistence economy, based on the self-consumption and sale of their remaining products. Artisanal cheeses and to a lesser extent kid meat are the main products that are marketed informally [1-2]. This type of smallholder goat enterprise has serious productive conditions that affect system competitiveness and sustainability. Among these limitations we can mention insufficient technical consultation of agricultural professionals, low use of inputs and low adoption of simple technologies in nutritional, genetic, reproductive and sanitary flock´s management. Within the sanitary problem, goat´s health has great relevance because in addition to damaging goat´s productivity, they can seriously affect family´s health by being exposed to possible man transmissible diseases. Although there are certain works carried out to identify the health problems of goats in different regions of the country [3-7], the available information is still scarce in Argentina and in Northwestern region. In order to characterize the general presence of infectious and parasitic diseases in the NOA goat flocks, a health survey was carried out on the owners, with biological samples for the diagnosis of different pathologies.
Materials and Methods
Study Area and Sampling Techniques
The study was conducted in 98 smallholder goat farms at the arid canyons and arid and semiarid valleys of northwestern Argentina between 1200 and 2700 m.a.s.l., in a mountainous relief with a predominance of elevations (Figure 1). Rainfalls are concentrated during summer in the arid (200 mm) and semiarid (400-600 mm) regions, with a dry period throughout the rest of the year.
Data collection:
Individual structured interviews were conducted from June 2014 to October 2017. The questionnaire included specific and brief questions and covered general data of the goat flock, such as stocks and management practices, number and categories of goats that died or suffered health problems during last year. Only those pathologies accompanied by a laboratory diagnosis or intervention of a veterinarian were recorded, except for those easily recognizable from a clinical observation made during the visit.
Sampling and clinical inspection
In each of the 98 SH dairy goat flocks, a total of 20 goats, some kids and yearlings, were clinically reviewed, along with the total of adult males, determining age by dental revision and eye, respiratory, diarrhea, skin, mouth and external parasites problems. On each SH flock 22 to 25 goat samples of blood and fecal matter were taken. Serum were processed to diagnose brucellosis using the buffered agglutination screening test and positive serum were confirmed by fluorescence polarization assay.
Serum for antibody detection against paratuberculosis, caprine arthritis encephalitis virus (CAEV), chlamydiosis, toxoplasmosis and caprine herpesvirus type 1 (CpHV1) by indirect immunoenzymatic assay (ELISA) were performed. Microscopic agglutination technique was used for leptospirosis antibody diagnosis.
From feces, helminth egg counts per gram (epg) and differentiation of genera by coproculture were made according Suarez [8].
Data Analysis
Data analysis was carried out using descriptive statistics (means, modes and percentages) according to Thrusfield [9].
Results and Discussions
Goat herd characteristics and management:
The surveyed producers are owners of small areas, mostly raising their animals on fiscal lands, without fences, or boundaries that separate their herds from the neighbors, sharing the feeding lands or sometimes the breeding males according to geographical accidents. Goat number per flock varied from 23 to 252 heads, with a median of 98.4 ± 88.2 caprines, excluding kids up to 45 days of age (45.4 ± 42.2) because their number at the time of the visits varied according to whether they had been consumed or sold. An important part (69.6%) of breeders keep Criolla biotypes mostly crossed with Anglo Nubian breeds, whereas a small proportion crossed with Saanen and the rest of producers (30.4%) raise other biotypes. Most of SH goat flocks (78.2%) feeds according to the season of the year: animals are taken to graze on natural pastures up the hills during summer-early autumn and the rest of the year are feeding lucerne, fodder crops or agricultural residues in the vicinity of their farm. The other (21.8%) SH flocks graze implanted pastures and are grain and hay supplemented. The breeding system is extensive with night enclosure. Goats are hand milked once daily early in the morning, with mostly 2 types of management: a) postpartum goats are released to grazing at noon after being milked and return to the pen before nightfall while usually kids stay in the pen and suck when goats return and then they are separated to do not suck overnight; b) postpartum milking begins when the kids are withdrawn for sale around 2 to 3 months of age. Most breeders (66.2%) apply a free mating system, holding bucks in the flock while to a lesser extent (33.8%) the producers make a seasonal mate period by introducing bucks for a short period. In many cases goats are matted by neighboring bucks. Generally, partition is concentrated in two periods, April-May (55.8%) or July-August (30.7%) and a smaller proportion (some goats kid twice in the year) is distributed between September and December. It should be noted that only 13.5% of animals are vaccinated, mainly against enterotoxaemia. Most farmers (81.2%) practice regular anti-parasitic treatment once (36.5%), twice (40.1%) or more than three times (23.4%) per year.
Health survey
Mean annual mortality rate per flock (excluding perinatal mortality) was 16.7±9.1%. Although perinatal mortality (dead kids during parturition or within 48 hours thereafter) rate is difficult to specify due to lack of accurate data, producer statements point to hypothermia, predation and unidentified infections as the most common causes. Regarding the mean abortion and still births occurrence within the flocks (9.6 ±8.1), producers declared that 42.9% of them were accompanied with placental retention. In some SH flocks the abortion rate reached more than 40%, indicating the seriousness of the problem; abortion in goats can be caused by various non-infectious and infectious agents [10], but several infectious agents can cause serious human diseases and as a consequence, abortion results in reproductive loss and also can have severe zoonotic implications. Firstly, smallholders identified kid respiratory (41.4%) and digestive disorders (49.9%) and adult goat respiratory problems (39.3%) as the major diseases that animal usually experienced.
Clinic mastitis were one of the main problems in the smallholder flocks (83.6%) due to the goat udder losses and its economic costs. Mastitis occurrence were mainly during rain periods and mud accumulation in pens. The mean morbidity and mortality rate of clinical mastitis was respectively 6.9±6.5 % and 1.6±1.5 %. Producer descriptions of mastitis death cases could be associated with events of gangrenous intramammary infections, which previously were observed in commercial dairy flocks due to Staphylococcus aureus [11]. Contagious ecthyma lesions on several occasions were observed in goat´s mouth and teats and 70.4% of the smallholders cited contagious ecthyma presence in their flocks, but only 17.3% said that orf was a serious kid problem. Subcutaneous abscesses were observed in 62.2% of flocks, and some of them were diagnosed clinical or bacteriological as caseous lymphadenitis by Corynebacterium pseudotuberculosis, but with low occurrence.
Infectious diseases
Table 1 shows the etiologic agents studied and their reactivity in the farm flocks and total animal surveyed seroprevalence. The survey showed that only one SH goat flock (1.02%) and one goat (0.04%) were brucellosis seropositive, which is consistent with previous observations carried out in the Quebrada of Humahuaca where a large survey found no positive animals [6] and reinforces the idea that with little sanitary work, all this region could become a brucellosis-free region and consequently with a very important competitive advantage. This differs markedly from the Chaco region of Salta, where the same serological survey showed a prevalence of brucellosis of 27%, as well as other Argentina´s surveys [5]. The results show a global presence of leptospirosis in 18.5% of the SH flocks, with low goat prevalence rates (Table 1). Serovar differentiation showed only the presence of Pomona infections ranged from low titres of 1: 200 to 1: 100. Toxoplasmosis (Toxoplasma gondii) positive SH flocks (61.6%) were seen with an average goat prevalence of 21.9%. In some SH flocks the prevalence in goats reached 30% to 80.1%, indicating dangerous levels for families that handle and milk animals and could get T. gondii infection through contact with their cats or by ingestion of raw milk or undercooked meat [12]. Other Argentina´s provinces surveys showed different average prevalences of 2.6% and 20% of positive goats [3,13]. Regarding chlamydiasis (enzootic abortion), which is caused by Chlamydophila abortus, the percentage of farms with seropositive goats was very high (73.7%), with an average goat prevalence of 18.7% with extremes of 6.7 and 82%. Until now, there is only little serological evidence about the presence of the disease in goats [14], and the real impact of this disease on Argentina´s goats production or human health is unknown, because only one chlamydiasis case was described by Bedotti et al. [15] with abortions (12%) and neonate mortalities. Positive diagnoses of paratuberculosis or Johne’s disease (Mycobacterium avium subsp. Paratuberculosis) were detected at farm flock level and goat level (Table 1). In one SH flock evidence of clinical cases could be diagnosed macroscopically at necropsy and isolating the bacteria, where only weight loss is the main sign observed (Micheloud, unpublished data).
Almost all the SH flocks (85.7%) had animals positive CpHV – 1, with positive goat prevalence extremes of 10 to 80%. Although it is not known the economic-productive implications could have the presence of the CpHV-1, it is known that it can affect goats of different ages, causing abortions, embryonic deaths and other mostly reproductive disturbances [16]. The data reported herein shows that CpHV-1 circulates in this region, which should be taken into consideration in cases of unexplained goat abortions. Seropositive SH goat farms and total goats to CAEV were show in Table 1. These positive results together with clinical cases diagnosis in the study region and as in other central regions of our country confirm the presence of CAEV in Argentina [17-18]
Parasitic diseases
Regarding the presence of ectoparasites diseases, the sucking lice (Linognathus stenopsis) were observed; producers indicated (87%) that lice are an important limitation for kid growth. Smallholders also declared nasal secretions that were diagnosed from the Oestrus ovis larval stages findings and cutaneous myiasis due to Cochliomya hominivorax, however for the goat SH located at arid regions these ectoparasites have less importance. Nematode egg counts per gram average according to the sampling arid and semiarid regions were respectively 182 and 1037 epg. Haemonchus and Trichostrongylus and secondly Teladorsagia were the prevailing nematode genera (Table 2). Sporadically eggs of Oesophagostomum, Trichuris, Skrjabinema and Moniezia were observed. It must be noted that these results should be interpreted considering that there was only one sampling date, impeding view seasonal variations of nematode infection. Also, the deworming influence on the flock epg values was unknow. These results agree with previous observations where Haemonchus contortus and Trichostrongylus colubriformis were the prevalent species in the region [19]. Goat farmers recognized the presence of liver fluke (Fasciola hepatica) in their flocks. Caprine prevalence of F. hepatica eggs in the feces was 51.6%, with counts between 1 to 10 eggs per gram. Previous studies showed clinical cases of Fasciolosis in these arid regions [20]. Cystic echinococcosis (CE) or hydatid disease is caused by the larval stage of the tapeworm Echinococcus granulosus. It was a neglected zoonosis, because 48.2% of the producers declared having seen cysts in liver and lungs during the slaughter of their animals. Previous study in dog feces (n= 43) in an arid circumscribed area showed a 45.5% seropositive samples [21]. This endemic zoonosis demonstrates a serious situation for public health, aggravated by the fact that only few producers in the present survey dewormed their dogs.
Conclusion
These results provide a study basis for the characterization of dairy goat breeding in the Northwestern Argentina region. The results highlight that the general goat management and hand milking is still traditional and that it can be improved from appropriate nutritional, reproductive and sanitary management. This investigation provides information of prevalence and the possible impact of diseases in these SH goat systems. The high rates of mortality as well as the most prevalent diseases that shorter the productive lifespan and the reproductive efficiency of the goats should be studied to improve these constrains on production.
To Know more about Dairy & Veterinary Sciences
Click here: https://juniperpublishers.com/index.php
No comments:
Post a Comment