Control of Coxiella burnetii shedding in a dairy goat herd by annual offspring vaccination.

A Coxiella burnetii vaccination program, targeting only doelings, was introduced on a German goat farm to curb bacterial shedding. In 2018, adults were vaccinated with a C. burnetii Phase I vaccine at three-weeks apart following pathogen diagnosis, with a booster administered six months later due to sustained high shedding. From 2018 to 2021, doelings received two vaccine doses without any further boosters. To assess the program's efficacy, vaginal swabs from up to 40 animals per age group were collected during kidding seasons from 2019 to 2022. Bulk tank milk (BTM) samples were gathered monthly from January 2018 to October 2022 to monitor herd-level shedding. Real-time PCR analysis determined genome equivalents in all three sample types. Serum samples were taken before the initial immunization and during the post-kidding season from up to 40 goats per age group annually from 2018 to 2022. Phase-specific ELISAs determined IgG Phase I and Phase II antibodies. Additionally, two serum samples per age group from 2022 were analyzed using a neutralization assay. A few goats continued shedding small quantities during subsequent kidding seasons. Although positive BTM samples decreased, they displayed an undulating trend. Most age groups exhibited robust IgG Phase I responses and lower IgG Phase II levels post immunization. Mean IgG levels remained elevated until the study ended compared to pre-vaccination levels in most age groups. Additionally, neutralizing antibodies were present regardless of IgG response. Overall, double vaccination induced lasting antibody levels, but did not entirely prevent C. burnetii shedding. The resilience of the observed humoral immune activity requires further investigation.

Relationships between body condition score, body weight and body measurements in alpacas.

BACKGROUND: The nutritional status in alpacas is often masked by their dense fibre coat. Its assessment is commonly approached by different body condition scores (BCS) that rely on manual palpation of defined anatomical regions. However, BCS is an important diagnostic tool to aid recognition of diseased South American camelids (SACs) and low BCS has been associated with conditions like anaemia and neutrophilia. For dose-dependent veterinary treatment, body weight (BW), that should be as accurate as possible, is required. As on-site weighing with scales is often not possible, BW can mostly only be roughly estimated. To date, it remains unclear whether BCS in alpacas provides reliable information on BW or the ratios of BW to body length commonly known as Body Mass Index (BMI) or Ponderal Index (PI). Equations to estimate BW based on body measurements are available in the literature. Nonetheless, respective equations were developed in growing alpacas or adult llamas and BCS was not included. RESULTS: To compare six different BCS approaches and to examine the relationship between BCS and BW, body measurements and BCS scores were recorded in a herd of 105 alpacas. The examined BCS approaches showed significant (p < 0.05) but poor to moderate positive correlations to BW, BMI or PI. A solely visual inspection of BCS, in contrast, was not correlated with BW, BMI or PI. Equations previously developed in other studies provided an accurate estimation of BW. Multiple linear regression showed that the accuracy in predicting BW could be further increased by adding BCS data and sex. CONCLUSION: Our observations indicate that most selected BCS approaches are not only important measures of nutritional status but can also be used to create more accurate models for BW calculation in alpacas. The study also supports the claim that a purely visual inspection of alpacas is not an adequate method to evaluate the nutritional status of these animals.

The influence of different examiners on the Body Condition Score (BCS) in South American camelids-Experiences from a mixed llama and alpaca herd.

Particularly in unshorn llamas and alpacas with a dense fiber coat, changes in body condition often remain undetected for a long time. Manual palpation of the lumbar vertebrae is hence a simple and practical method for the objective assessment of body condition in South American camelids (SAC). Depending on tissue coverage, a body condition score (BCS) of 1 (emaciated) to 5 (obese) with an optimum of 3 is assigned. To date, there is a lack of detailed information on the comparability of the results when the BCS in llamas or alpacas is assessed by different examiners. Reliability of BCS assessment of 20 llamas and nine alpacas during a veterinary herd visit by six examiners was hence evaluated in this study. A gold standard BCS (gsBCS) was calculated from the results of the two most experienced examiners. The other examiners deviated by a maximum of 0.5 score points from the gsBCS in more than 80% of the animals. Inter-rater reliability statistics between the assessors were comparable to those in body condition scoring in sheep and cattle (r = 0.52-0.89; τ = 0.43-0.80; κw = 0.50-0.79). Agreements were higher among the more experienced assessors. Based on the results, the assessment of BCS in SAC by palpation of the lumbar vertebrae can be considered as a simple and reproducible method to reliably determine nutritional status in llamas and alpacas.