Genetic Parameters of Somatic Cell Score in Florida Goats Using Single and Multiple Traits Models

Abstract

A total of 1,031,143 records of daily dairy control test of Spanish Florida goats were used for this study. The database was edited, and only the records of the first three lactations were kept. The final database contained 340,654 daily-test somatic cell counts from 27,749 daughters of 941 males and 16,243 goats. The evolution of this count in the last 14 years was analyzed following French and American international associations’ criteria for the risk of mastitis in goats, and confirmed the slight increase in SCS in the last years and the importance of this problem (50% of dairy control tests show a risk of suffering mastitis). For the genetic analysis, the SCS records were log-transformed to normalize this variable. Two strategies were used for the genetic analysis: a univariate animal model for the SCS assuming that SCS does not vary throughout the parities, and a multi-character animal model, where SCS is not considered as the same character in the different parities. The heritabilities (h2) were higher in the multiple traits models, showings an upward trend from the first to the third parity (h2 between 0.245 to 0.365). The genetic correlations of the same trait, as well as between breeding values (GVs) between different parities, were different from unity. The breeding values (EBVs) obtained for both models were subjected to a PCA: the first eigenvector (λ1) explained most of the variations (between 74% to 90%), while the second λ2 accounted for between 9% to 20% of the variance, which shows that the selection will be proportionally favorable but not equivalent in all parities and that there are some variations in the type of response.

Relationship between Somatic Cell Score and Fat Plus Protein Yield in the First Three Lactations in Spanish Florida Goats

“…In this breed, Jiménez-Granado et al [7] showed how the levels of this parameter have increased alarmingly over the last decade, which is consistent with the levels of mastitis perceived by the farmer. It is therefore considered necessary to establish a plan to control and prevent mastitis, which combines sanitary and management measures with the search for greater resistance to this disease.…”

“…A recent publication indicates that cumulative milk production in the period up to 240 days of lactation in the Florida breed has increased at a rate of 1.7% per year. However, this may, as a collateral effect, have increased potential infection problems, which is reflected in aspects such as somatic cell count (SCC), due to the constant interaction between the udder and the milking equipment [7]. Although a certain level of SCC may be tolerated as an indicator of resistance to infection, immunity and health, it may also represent risks to product quality and could result in economic losses.…”

Analysis of the genomic landscape of inbreeding in two divergent groups of Spanish Florida goats

“…Finally, DNAJC18 was located within the ROHi located in CHI7. Despite its function has not yet been reported in goats, it was related to heat stress resistance in cattle (Hu et al, 2020), a well‐known characteristic of Florida goats, that is, well‐adapted individuals to the hot temperatures and harsh environments in their area of influence in the south of Spain (Jimenez‐Granado et al, 2022).…”

“…The current breed census includes 28,243 individuals (27,423 dams and 820 bucks) located in 81 herds distributed in 14 Spanish provinces. The breeding programme was developed by the Asociación de Criadores de Cabra Florida (ACRIFLOR) and is mostly focused on selecting fertile individuals which can produce milk under the semi‐intensive harsh productive conditions of the Iberian Peninsula (extensive pasturelands and hot weather) (Jimenez‐Granado et al, 2022; Ziadi et al, 2021). The analysis of inbreeding levels in the Florida goat breed using molecular data is still missing and would be therefore of great interest to develop its breeding programme.…”

Survival analysis of productive life in Florida dairy goats using a Cox proportional hazards model

“…Nowadays, the breeding programmes for Spanish dairy goats are generally focused on improving milk production and milk composition traits (Menéndez‐Buxadera et al, 2010; Molina et al, 2018), or somatic cell score (Jimenez‐Granado et al, 2022), on morphological, and more recently, reproductive traits (Ziadi, Muñoz‐Mejías, Sánchez, et al, 2021; Ziadi, Muñoz‐Mejías, Sánchez Rodríguez, et al, 2021). However, the undesirable consequences have been widely reported of selection for high milk production on the health and fertility of animals, which decreases longevity (Oltenacu & Broom, 2010).…”