Browsing by Author "Maerten, C."
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- Padrões de crescimento no cavalo de desporto: aplicação de funções não-linearesPublication . Fradinho, M.J.; Assunção, D.; Costa, A.L.; Maerten, C.; Gonçalves, V.; Teixeira, A.; Fangueiro, L.; Bliebernicht, M.; Vicente, AntónioO conhecimento das taxas de crescimento mais adequadas a cada raça e tipo de utilização é fundamental para criadores e utilizadores. O presente estudo teve como objetivo caracterizar os padrões de crescimento de cavalos de desporto, nascidos e criados numa coudelaria de referência, em França, utilizando funções não lineares. Para o efeito, 72 poldros (39 machos e 33 fêmeas) das raças Hanoveriana e Oldenburgo foram periodicamente pesados e medidos, tendo sido obtidos 1.382 registos para o peso vivo (PV) e altura ao garrote (AG). Os dados foram recolhidos entre o nascimento e os 5 anos de idade, quando os cavalos já estavam em trabalho regular. Inicialmente, foram ajustadas várias funções não-lineares (Brody, Logistic, Gompertz, von Bertalanffy e Richards) utilizando o procedimento NLIN do SAS. Contudo, a equação de Richards y = A(1 – b.exp(-kt))M foi escolhida para a análise posterior por se tratar do modelo que melhor se ajustou às duas variáveis. As taxas de crescimento (GMD, kg/d ou cm/d) foram obtidas a partir da primeira derivada das equações e o efeito do sexo foi também avaliado. O PV médio à idade adulta foi de 623,2±14,1 kg e a altura ao garrote 172,9±1,3 cm. Segundo os modelos obtidos, as proporções (%) do PV adulto aos 6, 12, 24, 36 e 48 meses de idade foram, respetivamente, 39, 55, 74, 84 e 90%. As proporções da AG para as mesmas idades foram 80, 87, 93, 96 e 98%. Não foi observado dimorfismo sexual para a AG. No entanto, os modelos relativos ao PV são diferentes entre poldros e poldras (P<0,0001). As taxas de crescimento obtidas são semelhantes às descritas noutras raças de desporto para um crescimento moderado. O estudo apresentado demonstra que a equação de Richards pode ser utilizada para descrever com precisão o crescimento e o desenvolvimento de cavalos de desporto.
- Passive transfer of immunity: evaluation of mare colostrum quality and immunoglobulin G concentration in the new-born foalPublication . Costa, A.; Bliebernitch, M.; Maerten, C.; Assunção, D.; Vicente, António; Fradinho, M.Ingestion of high quality colostrum at birth is a determinant factor influencing a foal's health. As no antibodies pass through the mare's diffuse epitheliochorial placenta, failure of passive transfer (FPT) is an important cause of morbidity and mortality during the first month of foals’ life. FPT is defined as serum immunoglobulin G (IgG) concentration <400 mg/dl at 24 h of age. Mare's breed, age, nutrition and vaccination protocol have been described as having influence on colostrum quality, however, previous results reveal inconsistencies. The aim of this study was to evaluate the influence of different factors related to the mare on colostrum quality (IgG concentration) and its relationship with foal's IgG serum levels between 12 and 24 h of life. In this study, 131 mares of different breeds (Lusitano, French Trotter, Warmblood and Arabian/Anglo‐Arabian) and ages (4–10 years old) were monitored during four breeding seasons (2014–2017). All mares were from the same stud farm and had the same pre‐partum management, within each year. Colostrum quality was evaluated using a Brix refractometer (RHB‐32®) and IgG levels were accessed through a commercial kit (DVM Rapid Test II®). Considering the breed, Arabian/Anglo‐Arabian mares showed the lowest Brix % (p < 0.01). Age, parity and foaling season had no influence on colostrum quality (p > 0.05). However, a progressive increase of colostrum quality was observed until 2016 (p < 0.05) which could be ascribed to an improvement of stud farm practices such as nutrition and vaccination protocols. In the present study, a positive correlation between colostrum density and IgG foals’ serum concentrations was also detected (r = 0.335; p < 0.001) supporting the importance of good quality colostrum for passive transfer of immunity.
- Patterns of growth and development in warmblood horsesPublication . Fradinho, M.J.; Costa, A.L.; Maerten, C.; Fangueiro, L.; Bliebernicht, M.; Vicente, AntónioIntroduction: Non-linear functions have been used to characterize growth and development in some horse breeds. These functions adjust better to data and may have an easier biological interpretation. The objective of the present study was to characterize growth and development patterns in a population of warmblood horses (Hanoverian and Oldenburg breeds), from birth to 5 years of age. Materials and methods: A total of 2,852 records for body weight (BW), withers height (WH), girth (G) and cannon circumference (CC) were obtained from 81 foals (42 colts; 39 fillies) born and raised in a reference stud-farm in the south of France. Data were regularly collected between birth and 5 years of age, when horses were already on regular work. Several sigmoid growth functions were adjusted to BW, WH, G and CC data sets using the NLIN procedures of SAS. However, the Richards equation y = A(1 – b.exp(-kt))M was chosen for further analysis because it was the best fit model for all the variables. The effect of sex was also evaluated. Results: The mature BW was 619.4±18.6 kg and the mature size was 172.6±1.6 cm for WH, 198.8±2.2 cm for G and 21.0±0.2 cm for CC. According to average values found in literature, the proportions (%) of mature BW at 6, 12, 24, 36 and 48 months of age were, respectively, 40, 56, 75, 86 and 92 %. The proportions (%) of mature WH considered in the breeding programs for the two breeds, at the same ages were 82, 89, 95, 99 and 100%. In the present study, sexual dimorphism was not observed for WH. However, significant differences were found between males and females (P<0.001) in what concerns BW, G and CC models. Growth rates were in the range of those found for a moderate growth in other sport breeds. Conclusion: Growth and development in the warmblood horse can be accurately described by non linear functions.