A. I. Gelasakis

Bacterial subclinical mastitis and its effect on milk yield in low-input dairy goat herds.

The objectives of this study were (1) to record the major pathogens associated with subclinical mastitis (SCM), (2) to calculate their incidence during the milking period, and (3) to estimate the effect of SCM on daily milk yield (DMY) for goats reared under low-input management schemes. Dairy goats (n=590) of Skopelos and indigenous Greek breeds from 4 herds were randomly selected for the study. The study included monthly monitoring, milk yield recording, and bacteriological analyses of milk of individual goats during the course of 2 successive milking periods. Incidence and cumulative incidence were calculated for SCM cases. Moreover, 2 mixed linear regression models were built to assess the effects of (1) SCM and (2) different pathogens isolated from SCM cases, on DMY. The estimated incidence and cumulative incidence of SCM for the first and the second year of the study were 69.5 and 96.4 new cases of SCM/1,000 goat-months, and 24.1 and 31.7%, respectively. A total of 755 milk samples were subjected to microbiological examination, resulting in 661 positive cultures. Coagulase-negative and coagulase-positive staphylococci were isolated from 50.2 and 34.5% of the positive cultures, respectively. The incidence of infections (new infections per 1,000 goat-months) for the first and the second year of the study were 34 and 53 for coagulase-negative staphylococci, 23 and 28 for coagulase-positive staphylococci, 3 and 5 for Streptococcus/Enterococcus spp., and 5.5 and 9.1 for gram-negative bacteria. Goats with SCM had lower DMY when compared with goats without SCM (ca. 47g/d, corresponding to a 5.7% decrease in DMY). In particular, goats with SCM due to coagulase-positive staphylococci infection produced approximately 80g/d less milk (a reduction of ca. 9.7%) compared with uninfected ones, whereas SCM due to gram-negative bacteria resulted in approximately 15% reduction in DMY. Investigating the epidemiology of SCM and its effects on production traits is critical for the establishment of effective preventive measures against SCM and for the assessment of the sustainability of production in low-input dairy goat herds.

Bacterial subclinical mastitis and its effect on milk quality traits in low-input dairy goat herds

The objective of the study was to investigate and quantify the effects of subclinical mastitis (SCM) on the gross chemical composition of milk in low-input dairy goat herds. Dairy goats (n=590) of two native Greek breeds from four representative low-input farms were randomly selected and used in the study. Α prospective study was conducted, including monthly monitoring and milk sampling of the same individual goats during the course of two consecutive milking periods. Mixed linear regression models were built to assess how the chemical composition of milk was affected by (1) SCM and (2) the different pathogens isolated from SCM cases. Goats with SCM had lower milk-fat content (MFC), daily milk-fat yield (DMFY), milk-lactose content (MLC) and daily milk-lactose yield (DMLY), and slightly higher milk-protein content (MPC) and daily milk-protein yield (DMPY), compared with goats without SCM. Milk produced by goats with SCM due to coagulase-positive staphylococci and Mycoplasma agalactiae had significantly lower MFC, DMFY, MLC and DMLY, and higher MPC and DMPY, compared with the milk produced by healthy goats. Finally, goats with SCM due to coagulase-negative staphylococci had lower DMFY, MLC and DMLY and higher DMPY compared with the healthy ones.

Association of lameness with milk yield and lactation curves in Chios dairy ewes

The objective of the study was twofold: (i) to quantify the differences in daily milk yield (DMY) and total milk yield (TMY) between lame and non-lame dairy ewes and (ii) to determine the shape of lactation curves around the lameness incident. The overall study was a prospective study of lameness for the surveyed sheep population, with a nested study including the selection of matching controls for each lame ewe separately. Two intensively reared flocks of purebred Chios ewes and a total of 283 ewes were used. Data, including gait assessment and DMY records, were collected on a weekly basis during on-farm visits across the milking period. A general linear model was developed for the calculation of lactation curves of lame and non-lame ewes, whereas one-way ANOVA was used for the comparisons between lame ewes and their controls. Lameness incidence was 12.4 and 16.8% on Farms A and B, respectively. Average DMY in lame ewes was significantly lower (213.8 g, P < 0.001) compared with the rest of the flock, where DMY averaged 1.340 g. The highest DMY reduction in lame ewes was observed during the week 16 of the milking period (P < 0.001), whereas the reduction of DMY, for lame ewes, remained significant at P < 0.001 level from week 8 to week 28 of milking. Comparisons between lame and controls revealed that at the week of lameness diagnosis a significant DMY reduction (P ≤ 0.001) was observed in lame ewes (about 32.5%), which was maximised 1 week later (35.8%, P ≤ 0.001) and continued for several weeks after recovery, resulting in 19.3% lower TMY for lame ewes for the first 210 d of the milking period (P < 0.01). Moreover, at flock level, TMY for non-lame and lame ewes, as calculated by the general linear model, was 318.9 and 268.0 kg, respectively. The results of this study demonstrate evidence of significant financial losses in dairy sheep due to lameness which, however, need to be accurately estimated in further, more detailed, analyses.

Genetic profile of scrapie codons 146, 211 and 222 in the PRNP gene locus in three breeds of dairy goats

Polymorphisms at PRNP gene locus have been associated with resistance against classical scrapie in goats. Genetic selection on this gene within appropriate breeding programs may contribute to the control of the disease. The present study characterized the genetic profile of codons 146, 211 and 222 in three dairy goat breeds in Greece. A total of 766 dairy goats from seven farms were used. Animals belonged to two indigenous Greek, Eghoria (n = 264) and Skopelos (n = 287) and a foreign breed, Damascus (n = 215). Genomic DNA was extracted from blood samples from individual animals. Polymorphisms were detected in these codons using Real-Time PCR analysis and four different Custom TaqMan® SNP Genotyping Assays. Genotypic, allelic and haplotypic frequencies were calculated based on individual animal genotypes. Chi-square tests were used to examine Hardy-Weinberg equilibrium state and compare genotypic distribution across breeds. Genetic distances among the three breeds, and between these and 30 breeds reared in other countries were estimated based on haplotypic frequencies using fixation index FST with Arlequin v3.1 software; a Neighbor-Joining tree was created using PHYLIP package v3.695. Level of statistical significance was set at P = 0.01. All scrapie resistance-associated alleles (146S, 146D, 211Q and 222K) were detected in the studied population. Significant frequency differences were observed between the indigenous Greek and Damascus breeds. Alleles 222K and 146S had the highest frequency in the two indigenous and the Damascus breed, respectively (ca. 6.0%). The studied breeds shared similar haplotypic frequencies with most South Italian and Turkish breeds but differed significantly from North-Western European, Far East and some USA goat breeds. Results suggest there is adequate variation in the PRNP gene locus to support breeding programs for enhanced scrapie resistance in goats reared in Greece. Genetic comparisons among goat breeds indicate that separate breeding programs should apply to the two indigenous and the imported Damascus breeds.

Health and Welfare of Indigenous Goat Breeds from Dairy Farms in Greece

We address the dairy production system, health indicators, and welfare status of the goat industry in Greece. Initially, we describe the dominant production systems with their major trends and challenges for Greek goat herds’ sustainability and we characterize the most prevalent indigenous goat breeds. Afterward, we emphasize on health and welfare implications in low-input farming systems as they are determined by environmental exposure, housing and husbandry conditions, and the behavior of goats reared under these systems. Then, we summarize the most significant infectious and parasitic diseases and we describe them. We underline the significance of paratuberculosis, colibacillosis, contagious agalactia, clostridial diseases, pasteurellosis, scrapie and major endoparasites (trematodes, cestodes, and nematodes) and ectoparasites (flies, mange, ticks, and fleas). In the next section, we discuss the most suitable animal-based indicators to assess health and welfare status in goat farms and we present the results from a prospective epidemiological study regarding the prevalence and the incidence of the main health and welfare problems, on individual goat level in low-input goat herds. We conclude that among the factors undermining health and welfare status in goat herds in Greece, the most challenging ones include climatic change, weather exposition, inadequate feeding and water supply, inappropriate infrastructures and housing, infectious and parasitic diseases, as well as lack of farmers’ education and training on aspects regarding preventive medicine, herd health management, and human–animal relationship.