Several studies have shown a major development in height and cannon bone circumference in foals from birth to weaning and from different breeds. However, in Brazil, there is little information about foal development. For this reason, this study has used data on foals from seven different farms in Pernambuco, Northeast Brazil, where horses have a major economic importance. The aim of this study was to compare foal’s development from four breeds and to develop a regression formula in order to estimate such development. It was used data from 210 suckling foals (Arabians n = 18, Campolina n = 86, Mangalarga Marchador n = 42 and Quarter Horses n = 64), raised in similar management practices. Their height at withers, heart girth, and cannon bone girth were measured monthly from birth to weaning. Data we reanalyzed by ANOVA and Tukey Test, with P established in 5%. The highest mean of height at withers was observed in the Arabian foals, and it was similar to Campolina and Mangalarga Marchador foals. The last breed presented a higher percentage of gain in height (~36%) and higher heart girth. On the other hand, Campolina foals had the highest mean of cannon bone girth. There was a significant interaction between breed and development phase in heart and cannon bone girths. All regression for mulas obtained from this data was very significant, and it was showed that they can predict height at withers in the four breeds studied. Heart and cannon bone girths showed medium value of R2 and large significance. It is important to highlight that fetal programing produces significant impact on foal development, even after weaning. So, this study would have observed some more changes if its scope had been extended beyond this phase.
Studies in different countries with foals showed large body development between they born and just before the weaning principally in their height at withers and foals’ weight [
Horse population in Pernambuco is around 150,000 plus 100,000 donkeys and mules. These animals have large economical importance in different parts of this state and in Brazil [
It was used data from 210 suckling foals from four breeds (Arabians n = 18 foals, Campolina n = 86, Mangalarga Marchador n = 42, Quarter-Horses n = 64). These young horses were raised in seven different farms (Arabians n = 1, Campolina n = 2, Mangalarga Marchador n = 2, Quarter Horse n = 2) in the State of Pernambuco, Brazil, between 1998 and 2002. All farms where located at Agreste region in Pernambuco and had similar management practice, where mares and their foals received supplementation with pellets during late gestation and lactation, following NRC [
Foals’ measurements were made monthly, starting immediately after the foals’ born and finished when they had 6 months old (weaning). In these foals it was measured: height at whither, heart girth and cannon bone girth. All measurements were made following techniques described by Costa et al. [
Data were submitted to one-way ANOVA and two-way ANOVA (breed and phase of development), with P < 5%. Post hoc test was Tukey, when were needed and with P < 5%. Also linear regressions were developed to produce formulas that can be used to estimate each breed growth curve. Sigma Stat 3.0 was used to all statistical analysis. Results were expressed in mean ± standard error medium.
The results of this study showed that Arabians foals had large mean of height at withers when compared with Quarter Horse (P < 0.05) but was similar to Campolina and Mangalarga Marchador (P > 0.05) (
. The average of body measurements in four different breeds in Pernambuco, between birth and 6 months old (weaning).
Body measurements | Breed | |||
---|---|---|---|---|
Arabian | Campolina | Quarter Horse | Mangalarga Marchador | |
Height at withers | 112.80 ± 0.54 A | 111.30 ± 0.23 AB | 107.50 ± 0.30 C | 112.69 ± 0.32 AB |
Heart girth | 110.04 ± 0.86 B | 108.48 ± 0.37 B | 108.81 ± 0.42 B | 113.99 ± 0.54 A |
Cannon bone girth | 13.40 ± 0.09 D | 14.19 ± 0.04 A | 14.03 ± 0.04 B | 13.80 ± 0.05 C |
Observations: different letter at same line represents P < 0.05 by Tukey test.
. Results of foal’s height at withers from four different breeds, between birth and 6 months old (weaning).
Breed | Foal age | ||||||
---|---|---|---|---|---|---|---|
At birth | 1 month | 2 months | 3 months | 4 months | 5 months | 6 months | |
ARB | 94.87 ± 1.43 A | 105.56 ± 1.43 B | 110.31 ± 1.43 C | 114.68 ± 1.43 D | 118.12 ± 1.43 DE | 121.18 ± 1.43 EF | 124.68 ± 1.43 F |
CAMP | 93.55 ± 0.54 A | 102.24 ± 0.57 B | 108.14 ± 0.59 C | 112.96 ± 0.62 D | 117.15 ± 0.63 E | 120.54 ± 0.65 F | 124.48 ± 0.66 G |
MM | 93.71 ± 0.90 A | 102.05 ± 0.90 B | 108.47 ± 0.90 C | 114.47 ± 0.90 D | 119.33 ± 0.90 E | 123.55 ± 0.90 F | 127.26 ± 0.90 G |
QH | 90.66 ± 0.68 A | 98.82 ± 0.70 B | 104.18 ± 0.70 C | 109.03 ± 0.71 D | 112.67 ± 0.71 E | 116.58 ± 0.72 F | 120.46 ± 0.72 G |
Observations: ARB: Arabian; CAMP: Campolina; MM: Mangalarga Marchador; QH: Quarter Horse; Different letters at same line represents P < 0.001 using Tukey test.
and weaned in their heart girth (
In this study were observed significant interactions between breed and phase of development in heart and cannon bone girths (P < 0.05) but not in height at withers (
The body measurement average in this study detected that Arabians foals had large mean of height than Quarter Horse but similar to Campolinas and Mangalarga Marchador. However some of this result was not expected, because Campolinas horses have between 150 and 160 cm height at withers when they are adult animals [
Because this potential plasticity in horse’s height some researchers work with a percentage of adults height to better understand foals development, however adult height are not well defined in some breeds. Studies with Mangalarga Marchador suckling foals showed that breed obtain more percentage of adults height than Campolinas, ~85% and 75% respectively, before weaning [
Mangalarga Marchador horses had large heart girth when compared with all other three breeds. Values of heart girth can be used to determine body mass and foals during lactation this parameter got large increase when compared with gain in height at wither. Mangalarga Marchador and Arabians gain near 60% in this parameter
. Results of foal’s heart girth from four different breeds, between birth and 6 months old (weaning).
Breed | Foal age | ||||||
---|---|---|---|---|---|---|---|
At birth | 1 month | 2 months | 3 months | 4 months | 5 months | 6 months | |
ARB | 81.06 + 2.26 A | 96.37 + 2.2 B | 105.31 + 2.26 C | 113.25 + 2.26 D | 119.25 + 2.26 E | 124.25 + 2.26 EF | 130.75 + 2.26 G |
CAMP | 82.55 + 0.86 A | 95.03 + 0.9 B | 103.72 + 0.93 C | 110.54 + 0.98 D | 117.02 + 0.99 E | 124.22 + 1.03 F | 126.26 + 1.04 G |
MM | 85.02 + 1.43 A | 98.55 + 1.4 B | 107.42 + 1.43 C | 116.47 + 1.43 D | 124.07 + 1.43 E | 130.15 + 1.43 F | 136.22 + 1.43 G |
QH | 85.34 + 1.08 A | 95.34 + 1.1 B | 105.51 + 1.11 C | 110.10 + 1.13 CD | 116.71 + 1.13 E | 122.00 + 1.14 F | 126.62 + 1.14 F |
Observations: ARB: Arabian; CAMP: Campolina; MM: Mangalarga Marchador; QH: Quarter Horse; Different letters at same line represents P < 0.001 using Tukey test.
. Results of foal’s cannon bone girth from four different breeds, between birth and 6 months old (weaning).
Breed | Foal age | ||||||
---|---|---|---|---|---|---|---|
At birth | 1 month | 2 months | 3 months | 4 months | 5 months | 6 months | |
ARB | 11.09 ± 0.23 A | 12.31 + 0.23 B | 12.93 + 0.23 BC | 13.56 + 0.23 CD | 14.31 + 0.23 E | 14.53 + 0.23 EF | 15.06 + 0.23 F |
CAMP | 12.13 + 0.09 A | 13.20 + 0.09 B | 13.88 + 0.09 C | 14.33 + 0.10 CD | 14.86 + 0.10 E | 15.27 + 0.10 EF | 15.67 + 0.11 F |
MM | 11.35 + 0.15 A | 12.50 + 0.15 B | 13.31 + 0.15 C | 14.10 + 0.15 D | 14.66 + 0.15 DE | 15.15 + 0.15 EF | 15.53 + 0.15 F |
QH | 12.23 + 0.11 A | 13.03 + 0.11 B | 13.72 + 0.11 C | 14.21 + 0.12 D | 14.64 + 0.12 E | 15.02 + 0.12 EF | 15.33 + 0.12 F |
Observations: ARB: Arabian; CAMP: Campolina; MM: Mangalarga Marchador; QH: Quarter Horse; Different letters at same line represents P < 0.001 using Tukey test.
. Results of body measurements in foals by two-way ANOVA with repeated measurements, between birth and 6 months old (weaning).
Body measurement | Foal age | Breed | Interaction between foal age and breed |
---|---|---|---|
Height at withers | P < 0.001 | P < 0.001 | P > 0.05 |
Heart girth | P < 0.001 | P < 0.001 | P = 0.034 |
Cannon bone girth | P < 0.001 | P < 0.001 | P = 0.024 |
. Regression formulas for height at withers, heart girth, and cannon bone girth in foals from four different breeds, between birth and 6 months old.
Measurement | Formula | R | R2 | P value |
---|---|---|---|---|
Arabians | ||||
Height at withers | HW = 94.420 + (4.589 *Age) | 0.904 | 0.818 | <0.001 |
Heart girth | HG = 78.786 + (7.813 *Age) | 0.935 | 0.875 | <0.001 |
Cannon bone girth | CBG = 10.871 + (0.633 *Age) | 0.868 | 0.754 | <0.001 |
Campolina | ||||
Height at withers | HW = 91.152 + (5.032 *Age) | 0.864 | 0.746 | <0.001 |
Heart girth | HG = 78.936 + (7.378 *Age) | 0.817 | 0.668 | <0.001 |
Cannon bone girth | CGB = 11.913 + (0.571 *Age) | 0.729 | 0.531 | <0.001 |
Mangalarga Marchador | ||||
Height at withers | HW = 90.621 + (5.518 *Age) | 0.918 | 0.842 | <0.001 |
Heart girth | HG = 80.639 + (8.338 *Age) | 0.915 | 0.837 | <0.001 |
Cannon bone girth | CGB = 11.057 + (0.686 *Age) | 0.837 | 0.701 | <0.001 |
Quarter Horse | ||||
Height at withers | WH = 88.341 + (4.786 *Age) | 0.815 | 0.664 | <0.001 |
Heart girth | HG = 81.768 + (6.758 *Age) | 0.822 | 0.675 | <0.001 |
Cannon bone girth | CBG = 11.988 + (0.510 *Age) | 0.780 | 0.608 | <0.001 |
Observations: Foal age in months; WH = height at withers; HG = heart girth; CBG = cannon bone girth.
between birth and weaning, differently from Campolina and Quarter Horses, but in this parameter we did not obtain the percentage from adult horse. Hintz et al. [
The cannon bone girths are associated to bone characteristic and the average of this parameter in this research showed significant difference between all three breeds. Interesting, Campolina, which are heavier breed developed in Brazil, had large cannon bone girth followed by Quarter Horse, Mangalarga Marchador and Arabs (P < 0.05).
Different factors are associated with modulation of the development in young horses and breeds’s of horses. All animals in this actual research were raised in pasture and are supplemented with concentrate, which follow NRC 1987 suggestions, and during dry season (summer) farm owners supplemented their animals with Tifton and Cost-Cross hay and Elephant grass. Horse can be raised on pasture with supplementation with grain have normal growth and development [
The fetal programing produces significant impact on foals’ development independently of their breed. Different research had shown the importance of fetal development and programing to postnatal development and metabolism [
In this study, there was a significant interaction between breed and development phase for heart girth and cannon bone girth measurements. Also, the regression formula obtained with the suckling foal data can be used to predict height at withers for the four studied breeds. Finally, as fetal programing may influence postnatal development, there may be some differences in after-weaning measurements. Therefore, we suggest that more measurements in this period be done in order to complete and improve the understanding of equine development.