7th World Congress on Genetics Applied to Livestock Production, August 19-23, 2002, Montpellier, France

GENETIC AND PHENOTYPIC PARAMETERS FOR LINEAR BODY MEASUREMENTS OF THE , BRAZIL

R. Falcão1, C. McManus1, A. Spritze1, I. Chagas1, C. Vellosa1 and D. Costa2

1 Faculdade de Agronomia e Medicina Veterinária, Cx Postal 04508, Universidade de Brasília, Brasília, DF, 70910-900, Brazil 2 Associação Brasileira dos Criadores do Cavalo Campeiro, Curitibanos, SC, Brazil

INTRODUCTION The main agricultural activities in Santa Catarina State are corn, cassava and wheat. Swine rearing is also important and cattle and horse rearing are minor activities. Santa Catarina is the most mountainous state of Brazil with more than 77% higher than 300m above sea level. The state has 5 zones including costal, remnant Atlantic rainforest and high open rangelands. There is no dry season with mean daily temperature 16.5oC (with an 8-10oC variation). In a recent work by Cothran et al. (1998) on the Pantaneiro horse, its relationship with 73 other breeds including 13 Iberian and South American breeds was studied. The Campeiro horse from the Southern Highlands of Brazil was not included in this study and it is rarely mentioned in textbooks and scientific papers on horse breeds in Brazil or elsewhere. Spanish Jesuits brought from Spain and Portugal to Brazil in 1546 which were subjected to hundreds of years of natural selection.. In 1912 a Belgian known as Dr Vincent started selecting from the resultant wild herd and crossbred these with English and Arabian horses from France which gave rise to the Campeiro. Today restricted small herds can be found in the Santa Catarina highlands between Lages and Curitibanos (Mariante and Cavalcante, 2000). The official Herd Book shows a total of 498 horses registered since its creation in 1985 and a decline in the number of animals being registered is noticed. This along with the disappearance of natural grasslands in the area make this a candidate for extinction and research is necessary to ascertain whether it is worthwhile trying to save this genetic resource or not. The objective of this study is to calculate genetic and phenotypic parameters for linear body measurements and body indices on the Campeiro Horse.

MATERIAL AND METHODS Data was available on 498 horses registered by the Brazilian Association of Campeiro Horse Breeders. This included individual data on 15 linear traits (Shoulder Height (SH), Mid back height (MBH), Withers height (WH), Back height (BH), Head length (HL), Neck Length (NL), Back length (BL), Shoulder length (SL), Hip length (HiL), Body length (BOL), Head width (HW), Chest width (CW), Hip width (HIW), Chest circumference (CC), Cannon bone circumference (CBC)), space under horse (SUH), coat color, temperament and nine subjective traits taken at registration. Body indices and weight were calculated from Standard Formulae (Torres and Jardim, 1987) where Pectoral Index (PI)= WH/SUH; Dactyl-Thoracic Index (DTI) = CBC/CC ; Weight (BW) = CC3x80; Length Index (LI) = SH/BL ; Body Index (BI)= BL/CC; Thorax Index (TI) = CW/BH; Conformation Index (CI) = CC2/BH ; Work Index (WI) = CC2 x56/BH and Work Index2 (WI2)= CC2 x95/BH ; Compact Index (COI) = Weight (kg)/BH(cm) and Compact Index2 (COI2)= Weight (kg)/(BH(cm)-100). The effect of sex of animal, month,

Session 05. Communication N° 05-17 7th World Congress on Genetics Applied to Livestock Production, August 19-23, 2002, Montpellier, France

age and year of registration as well as coat colour on the measurements were investigated and genetic and phenotypic parameters were estimated using MTDFREML (Boldman et al., 1995).

RESULTS AND DISCUSSION Tables 1 and 2 present genetic and phenotypic correlations between the characteristics measured as well as calculated heritabilities for these traits. Phenotypic correlations between height, length, width and perimeter measurements are in general positive and vary from high (between height measures except with BH) to low (between back length and other traits). The highest correlation was between shoulder height and hip height (0.924), which is desirable as these traits are related to the walk and resistance of the animal (Zamborlini,1996). For an animal to be well proportioned it is important, according to Ribeiro (1998) that the height of the hip should be the same as the shoulder and the high correlation helps in maintaining this relationship during the selection process. This estimate is close to that found in the Marchador (0,90) by Zamborlini (1996). Negative correlations are observed between shoulder length and back length (-0.055), head width and neck length (-0.031), chest width and back length (-0,023), thorax perimeter and neck and head length (-0.012 and 0.028), as well as cannon bone perimeter ad head and neck length (-0.021 and –0.192). All these negative correlations are of low magnitude.

Table 1. Genetic (above diagonal) and phenotypic (below diagonal) correlations and heritabilities (on diagonal) of linear body measures on Campeiro Horses in Brazil

SH MBH WH BH HL NL BL SL HIL BOL HW CW HIW CC CBC SH 0.31 1.000 1.000 1.000 1.000 0.650 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 MBH 0.808 0.56 1.000 1.000 1.000 0.650 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 WH 0.924 0.799 0.10 1.000 1.000 0.650 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 BH 0.200 0.141 0.175 0.06 1.000 0.990 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 HL 0.119 0.106 0.134 0.029 0.12 0.970 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 NL 0.218 0.295 0.197 0.013 0.385 0.06 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 BL 0.167 0.219 0.146 0.194 0.031 0.258 0.56 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 SL 0.239 0.192 0.219 0.090 0.166 0.056 -.055 0.05 1.000 1.000 1.000 1.000 1.000 1.000 1.000 HIL 0.325 0.284 0.266 0.146 0.207 0.320 0.262 0.164 0.04 1.000 1.000 1.000 1.000 1.000 1.000 BOL 0.382 0.368 0.420 0.192 0.014 0.171 0.253 0.009 0.210 0.10 1.000 1.000 1.000 1.000 1.000 HW 0.201 0.095 0.187 0.159 0.127 -.031 0.013 0.229 0.104 0.058 1.00 1.000 1.000 1.000 1.000 CW 0.185 0.155 0.158 0.004 0.284 0.341 -.023 0.246 0.228 0.057 0.070 0.93 1.000 1.000 1.000 HiW 0.295 0.245 0.290 0.199 0.200 0.152 0.256 0.263 0.346 0.223 0.262 0.240 0.12 1.000 1.000 CC 0.264 0.158 0.246 0.251 -.012 -.028 0.006 0.135 0.065 0.202 0.150 0.166 0.208 0.97 1.000 CBC 0.328 0.199 0.315 0.178 -.021 -.192 0.090 0.117 0.061 0.182 0.221 0.020 0.229 0.282 0.11 See material and methods for abbreviations

Most of the phenotypic correlations are low and negative except those with thorax perimeter which has a high correlation with BW, WI, WI2, COI and COI2, as well as with the indices. The highest correlation is with BW and COI (0.992) and the lowest between CC and BI (-

Session 05. Horse breeding Communication N° 05-17 7th World Congress on Genetics Applied to Livestock Production, August 19-23, 2002, Montpellier, France

0.848). The index heritabilities are low except for CI, WI, WI2, COI and COI2, which have a heritability of unity. These may therefore be useful selection criteria for this breed.

The heritability of height, length, width and perimeter traits are very variable, varying between 1.00 head width and 0.04 for BOL. It can be seen that traits closely evolved with work capacity such as chest width (0.93) and thorax perimeter (0.97) are high, and these traits are highly correlated with each other as well as work indices WI and WI2. This high heritability means that selection for these traits should be successful. It should not be forgotten that an extremely wide thorax may cause low resistance in the animal as well as susceptible to accidents (Zamborlini, 1996).

Table 2. Genetic (above diagonal) and phenotypic (below diagonal) correlations and heritabilities (on diagonal) of body indices on Campeiro Horses in Brazil

SUH PI DTI BW LI BI TI CI WI WI2 COI COI2 SUH 0.06 1.000 1.000 0.30 1.000 1.000 1.000 1.000 -1.000 1.000 1.000 1.000 PI 0.526 0.12 1.000 0.28 1.000 1.000 1.000 1.000 -1.000 1.000 1.000 1.000 DTI 0.013 0.060 0.23 0.30 1.000 1.000 1.000 1.000 -1.000 1.000 1.000 1.000 BW -0.208 -0.074 -0.587 0.23 1.000 1.000 1.000 1.000 -1.000 1.000 1.000 1.000 LI -0.132 -0.123 -0.031 0.062 0.06 1.000 1.000 1.000 -1.000 1.000 1.000 1.000 BI 0.044 0.004 0.890 -0.659 0.200 0.02 1.000 1.000 -1.000 1.000 1.000 1.000 TI 0.490 0.111 -0.092 -0.087 -0.048 -0.052 0.07 1.000 -1.000 1.000 1.000 -1.000 CI -0.237 -0.064 -0.707 0.968 0.099 -0.774 -0.063 1.00 -1.000 1.000 1.000 -0.780 WI -0.237 -0.064 -0.707 0.968 0.099 -0.774 -0.063 1.000 1.00 1.000 1.000 -0.560 WI2 -0.237 -0.064 -0.707 0.968 0.099 -0.774 -0.063 1.000 1.000 1.00 1.000 -1.000 COI -0.251 -0.074 -0.610 0.992 0.091 -0.679 -0.088 0.987 0.987 0.987 1.00 -0.770 COI2 -0.335 -0.066 -0.620 0.904 0.156 -0.681 -0.085 0.963 0.963 0.963 0.952 1.00 See material and methods for abbreviations

These heritabilities differ from others in the literature (Zamborlini, 1996 ; Miserani, 2001). The history and selection of this breed is obviously different from the others and the herd book is small which may cause these differences.

Low heritabilities may indicate poor measuring techniques and difficulty in measuring animals that are constantly moving. It should be noted that the standard error on these estimates is high due probably the low number of observations and poor connectiveness between the animals. Phenotypic correlations varied widely, the highest correlations being between height measures and some index measures (CC and CBC with WI and COI).

Genetic correlations were in general close to unity (Table 1 and 2). This may be a reflection of the poor structure of the data (few animals with single generation data) or biases during measurement where the individual preferences of the evaluator influenced in the final measurement. While several evaluators were used over the years a single evaluator was present at all the registrations. Weight, COI2 and NL varied from this norm.

Session 05. Horse breeding Communication N° 05-17 7th World Congress on Genetics Applied to Livestock Production, August 19-23, 2002, Montpellier, France

CONCLUSION There is a need to further study this genetic resource as to date there is little and the results shown here suffer from large errors and may change with additional information. Any breeding program with this horse should take into consideration maintenance of the genetic variation as it is threatened with extinction due to crossbreeding with other breeds in the region. These horses are important for services such as leisure, as well as dealing with cattle in open range lands and selection should maintain these traits as well as their rusticity. There is also a need to carry out studies on inbreeding as the data here only considered one generation of animals.

REFERENCES Boldman, K.G.L., Kriese, L.D. and van Vleck, C.P. et al., (1995) ”A manual for the use of MTDFREML”, USDA-ARS, 120p. Cothran, E.G., Santos, S.A. and Mazza, M.C.M. et al. (1998) Genet. Mol. Biol. 21 : 343-349 Mariante, A. and Cavalacante, N. (2000) “Animals of the Discovery” EMBRAPA, Brazil Miserani, M.G. (2001) Master´s Dissertation, University of Brasilia, Brasília, Brazil Torres, A.P.and Jardim, W.R. (1987) “Criação do cavalo e de outros eqüinos” Nobel, SP. Ribeiro, D.B. (1988) “O Cavalo: Raças, qualidades e defeitos” Editora Globo Rural. Rio de Janeiro. 290 p. SAS (1999) User´s Guide, Cary, Indiana Zamborlini, L. and Pereira, J.C.C. (1996) “Melhoramento Genético Aplicado aos Equinos” Belo Horizonte, Brazil, 476p.

Session 05. Horse breeding Communication N° 05-17