Alejandro Larriestra

Universidad Nacional de Villa María | UNVM · Medicina Veterinaria

The cow somatic cell count (CSCC) is an indicator of intramammary infection (IMI), and it has been used to make decisions at dry-off about selective dry cow therapy (SDCT). This study assessed ex-ante the economic impact of implementing SDCT under milk production conditions in Argentina, using CSCC to identify cows with IMI at dry-off. Eighty six c...

The economic evaluation of mastitis control is challenging. The objective of this study was to perform the economic evaluation of mastitis control, under different intervention scenarios, quantifying the total cost of mastitis caused by S. aureus in Holstein cows in Argentina. A model was set for a dairy herd of Holstein cows endemically infected w...

The replacement program in a dairy farm represents the second or third largest cost in a dairy operation. This study aimed to characterize and typify the practices related to the dairy heifer replacement program and describe the growth, development, and health parameters during this period in commercial dairy herds in Trenque Lauquen. A cross-secti...

Estimación de pérdidas económicas causadas por Trypanosoma vivax en un rodeo lechero de Argentina A b d a l a , A. A. 1; L a r r i e s t r a , A. J. 2; S i g n o r i n i , M. 3 1INTA-EEA, Rafaela, Santa Fe Argentina. 2Facult.Agrony Vet.UNRC, Resumen Abdala, A.A.; Larriestra, A.J.; Signorini, M.: Estimación de pérdidas económicas cau-sadaspor Trypan...

Objective The aim of this study was to evaluate the effects of adding milk replacer to milk fed to calves during their first month of life on intake, performance, and health under 2 milk feeding programs. Materials and Methods Sixty female Holstein calves were blocked at birth by dam parity and assigned in a randomized block design to 1 of 4 treat...

En Argentina T. vivax fue descrito por primera vez en 2006 afectando ganado de carne de la Provincia de Formosa. Durante el verano/otoño de 2016/2017 se observaron los primeros brotes en la zona central de la Provincia de Santa Fe, afectando algunos rodeos lecheros. Se describe el impacto que este hemoparásito produjo en un establecimiento lechero...

El objetivo de este trabajo fue estimar la incidencia de mastitis clínica (MC) en tambos e identificar factores individuales asociados a nuevos episodios. Nueve tambos del tipo semipastoril que aplicaban medidas de control y prevención de la mastitis, fueron incluidos y visitados dos veces con un intervalo de 15 días. Una muestra aleatoria de vacas...

This paper aims to describe clinical disease incidence in early lactation and explore its association with fertility and culling in 13 commercial grazing dairy herds in Uruguay. Seven farms with less than 250 dairy cows considered small herds (SH) with a herd size average ± (SD) of 144 ± (56) cows and six farms with more than 500 cows considered la...

Background This investigation was carried out to gain more insight about the preference of veterinarians on the implementation of an udder health programme (UHP) in a dairy farm. Methods A choice experiment was designed to elicit the preferences of the participants. The study population consisted of 36 veterinarians from Argentina specialised on m...

Information on sources of variation in feed and diet characteristics is needed to develop appropriate strategies to reduce uncertainty and to separate true variation from that associated with measurements. The objectives were to determine sources of variation in DM content and particle size distribution in corn silage (CS) and TMR. Ten dairy farms...

The predictive values of plasma non-esterified fatty acid (NEFA), beta-hydroxybutyrate (BHB), cholesterol, albumin and calcium to predict risk of peripartum diseases in primiparous (PP) and multiparous (MP) Holstein cows was investigated. Besides it was assessed if the health status interacted with parity on body condition score and metabolic profi...

Coagulase-negative staphylococci (CNS) are a common cause of bovine subclinical mastitis (SCM). The prevalence of CNS species causing SCM identified by genotyping varies among countries. Overall, the antimicrobial resistance in this group of organisms is increasing worldwide; however, little information exists about a CNS species resistant to antib...

A survey was conducted to evaluate the magnitude and variation of clinical mastitis among dairy herds. Prevalence, cumulative incidence and incidence rate were estimated, exploring risk factors at cow level and economic consequences. A cross sectional convenience sample of 2,535 Holstein-Friesian milking cows from 19 herds was the study population....

A survey was conducted to evaluate the magnitude and variation of clinical mastitis among dairy herds. Prevalence, cumulative incidence and incidence rate were estimated, exploring risk factors at cow level and economic consequences. A cross sectional convenience sample of 2,535 Holstein-Friesian milking cows from 19 herds was the study population....

Resumen El objetivo de este estudio fue determinar la incidencia de diarrea y mortalidad en terneros de 2 a 65 días de edad y los factores de riesgo asociados. En una cohorte retrospectiva de un establecimiento de la zona rural de Córdoba, Argentina, 957 terneros Holstein provenientes de 5 lecherías fueron seguidos hasta los 65 días de vida. Sexo d...

The aim of this study was to perform a current molecular characterization of bovine pathogenic Escherichia coli strains isolated from random samplings in Argentinean dairy farms. Rectal swabs were obtained from 395 (63.7%) healthy and 225 (36.3%) diarrheic calves, belonging to 45 dairy farms in Cordoba Province, Argentina. E. coli isolates were exa...

The aim of this study was to perform a current molecular characterization of bovine pathogenic Escherichia coli strains isolated from random samplings in Argentinean dairy farms. Rectal swabs were obtained from 395 (63.7 %) healthy and 225 (36.3 %) diarrheic calves, belonging to 45 dairy farms in Cordoba Province, Argentina. E. coli isolates were e...

The aim was estimate the daily direct cost and the expenditures due to mastitis control and prevention, evaluating their magnitude and variation among dairy farms. A random sample of dairy farms was the study population. Forty eight farms were visited once. The visit included a clinical mastitis check-up of lactating cows, a visual inspection of mi...

The objective of this study was to investigate the prevalence of different mastitis pathogens in Argentinean dairy farms. Composite milk samples were collected of 2296 cows from 51 randomly selected herds in Córdoba, Argentina. Somatic cell count was determined in all samples and bacterial examination of the milk samples with a SCC exceeding 200,00...

San Roque reservoir (31º22`S, 64º27´W, 2478 ha) is located in the province of Córdoba (Argentina). The silverside Odontesthes bonariensis is the dominant and most important sport fishing species in this reservoir and sustains a strong socioeconomic activity. The study aims were description of the food items, the seasonal variation of the parasitic...

Cryptosporidiosis is a common infection in cattle worldwide, economic losses are related to diarrhea and the extra costs that diarrheic calves demand. C. parvum is known to infect humans and is recognized as the major zoonotic species. The objective of this study was the molecular identification of C. parvum in positive calves. A cross sectional st...

The potential association between hygienic conditions in the environment of lactating cows and the presence of gliotoxinogenic Aspergillus fumigatus strains was studied. Milk samples (individual cow's milk [ICM], bulk tank milk [BTM]) from 44 dairy farms were sampled. In ICM samples, eight different species of Aspergillus were identified. A. flavus...

The somatic cell count (SCC) is considered an important indicator of intra-mammary infection (IMI). The purpose of this study was to determine the accuracy of both SCC and culture to detect IMI and their conditional dependence by means of latent class methods. This study involved 175 dairy cows from 2 herds with different udder infection prevalence...

Bovine mastitis produces a wide variety of problems in the dairy farm. The treatment of this disease is based on the use of antibiotics which are not always effective. These drugs are also responsible for the presence of residues in the milk and the increase of antibiotic-resistant strains. Probiotic products were proposed as a valid alternative to...

On-farm implementation of good production practices (GPP) and effective translation of food safety knowledge to food-animal producers are recommended to achieve a safer food supply. A pilot study was conducted during 2009-2010 to assess the knowledge and attitudes towards food safety and reported use of GPp among a sample of 930 cattle producers in...

RESUMEN Se evaluó la calidad bacteriológica del agua de pozo y del agua de lavado en una muestra aleatoria de 50 tambos distribuidos en la cuenca lechera de Villa María (Córdoba), Argentina. La visita a los tambos se realizó en 2007. Un 46 % y un 24 % de los tambos presentaron recuentos de aerobios mesófilos superiores a 500 UFC/ml en el agua de la...

La implementación de buenas prácticas de producción (BPP) en establecimientos pecuarios y la traducción efectiva de conocimiento sobre inocuidad de los alimentos a productores agropecuarios se recomienda para un suministro de alimentos más seguros. Un estudio piloto fue realizado durante 2009-2010 para evaluar el conocimiento y las actitudes hacia...

Streptococcus uberis is a major environmental mastitis-causing pathogen. The infections are predominantly subclinical and are frequently undetected and untreated for extended periods of time. More information about the pathogenesis of S. uberis mastitis would be useful. To our knowledge, no experimental studies into the mastitis pathogenesis caused...

The objectives of this study were to estimate calf and herd prevalence of Cryptosporidium spp. and Giardia spp., the herd prevalence clustering, spatial distribution according to soil type and shedding patterns in dairy calves from Cordoba, Argentina. Six hundred twenty calves younger than 7 weeks of age from 43 dairy herds were sampled. Samples we...

Mastitis, inflammation of the mammary gland, is one of the most costly and complex diseases of the dairy industry. The economic consequences of bovine mastitis are related to treatment, production losses, culling and changes in milk quality. These factors have a substantial impact on the farm business. The complexity is reflected in the numerous ca...

Bacteriological contamination of well water and wash water in a random sample obtained from 50 farms from Villa María (Córdoba) dairy area, Argentina, was evaluated during a visit in 2007. Forty six percent and 24 % of farms showed an aerobic mesophilic bacteria count higher than 500 CFU/ml in wash water and well water, respectively. Escherichia co...

Mastitis, inflammation of the mammary gland, is one of the most costly and complex diseases of the dairy industry. The economic consequences of bovine mastitis are related to treatment, production losses, culling and changes in milk quality. These factors have a substantial impact on the farm business. The complexity is reflected in the numerous ca...

The aim was to carry out a survey of aflatoxin M(1) (AFM(1)) in raw whole milk from bulk tanks. The sample collection was performed in farms located in one the most important milk-production zones in the centre of Argentina. A total of 94 samples of milk from 47 dairy farms were analysed. AFM(1) analysis involved the use of liquid chromatography-ta...

The pejerrey Odontesthes bonariensis is the most important freshwater fish of Argentina central region. The present study was conducted to describe the seasonal variation of parasitism in O. bonariensis from La Viña reservoir (31 degrees 17'S, 65 degrees 01'W), located in the province of Córdoba, Argentina. Between years 1999 and 2002, 573 fishes w...

One thousand and ten weaned pigs that were reared in 1 nursery in Iowa from weaning (17 +/- 2 days ) until 10 weeks of age were evaluated. A weaning weight threshold of 3.6 kg maximized the sensitivity and specificity to correctly predict the likelihood of dying or being light in weight at exit from the nursery (< or = 14.5 kg). Weaning weight < or...

A path analysis of the factors associated with seasonal variation of breeding failure in sows. Can. J. Anim. Sci. 85: xxx–xxx. Data pertaining to 868 904 services of sows from 58 Canadian herds for the period 1999 to 2003 were retrieved from the PigCHAMP data share database and subjected to path analysis to evaluate the effect of number of insemina...

A decision model to aid in selecting treatments for weaned pigs was developed and tested, with the purpose of reducing nursery mortality and improving weight gain. Interventions evaluated were to not treat pigs, to treat the whole population, or to treat only a subgroup of pigs below a certain weaning weight (target treatment). Outcome was characte...

Large scale production systems for swine are frequently organized in a hierarchical structure. Consequently, important production parameters, such as mortality and culling, can be analyzed at different levels. The major aims of this study were to assess variance components (VC) of mortality and culling rates attributed to sites and to barns within...

Several internal and external parasites have been reported in wild population of pejerrey, Odontesthes bonariensis, although most of the studies conducted have emphasized on taxonomy descriptions. The aims of this research were to describe the seasonal variation and the age pattern of the Contracaecum sp. prevalence, and, to characterize the associ...

The present study investigated risk factors for mortality in grow-finishing pigs of 137 pig herds belonging to one integration company during a period of 2.5 years. Mortality data, expressed as the number of dead pigs divided by the number of pigs placed in the fattening unit were investigated retrospectively. The following potential risk factors w...

The objective of this study was to evaluate the preserving capacity of a commercial, long-term boar semen extender beyond 4 days in terms of farrowing failure and total born per litter in sows and gilts. Data from 21 farms were subjected to logistic and linear regression analyses to assess the effect of parity (2-5, > 5 and gilts), wean-to-service...

Objectives: To investigate overall and weekly mortality in grow-finish pigs in a large multi-site production system, and to assess the associated financial losses. Materials and methods: Between January 1996 and January 2000, mortality was investigated retrospectively in 14 swine complexes, including 146 closeouts comprising 1,345,127 pigs. Overall...

A vaccine was developed against bovine mastitis based on inactivated, highly encapsulated Staphylococcus aureus cells; a crude extract of Staph. aureus exopolysaccharides; and inactivated, unencapsulated Staph, aureus and Streptococcus spp. cells. This vaccine was tested on 30 heifers during a 7-mo period. The 30 heifers were randomly assigned to t...

A vaccine against bovine mastitis was developed. The vaccine was based on inactivated, highly encapsulated Staphylococcus aureus cells; a crude extract of Staph. aureus exopolysaccharides; and inactivated unencapsulated Staph. aureus and Streptococcus spp. cells. In this study, the vaccine was evaluated in 164 cows from two commercial dairies (A an...