Reduced high intensity training distance had no effect on VLa4 but attenuated heart rate response in 2-3-year-old Standardbred horses

Table 1 Parameters used to balance training groups

Group	Horse	Breeder	Breeding index	Sire	French, %	Inbreeding coefficient, %	Age, days	Height, cm	X-ray findings ¹	Conformation remark	IIA/IIB
C	1	A	106.5	1	20.6	7.2	580	153	c	0	0.73
C	2	A	101	1	0	15.8	653	152	d	2	1.34
C	3	A	107.5	1	0	13.5	535	155		0	1.58
C	4	A	109.5	3	26.5	7	630	157.5		1	1.27
C	5	B	115.5	2	0	13.5	611	156		0	1.86
C	6	B	114	2	10.3	8.5	600	157	b	1	1.58
C	7	B	106.5	4	11.0	7.7	567	153	d	2	1.50
C	8	C	-	5	10.2	11.1	587	154	a	1	0.83
Mean C-group			108.6		9.8	10.5	595	154.7		7*	1.34
R	9	A	107	1	0	1.8	585	155.8	c	1	1.23
R	10	A	-	1	15.3	9.6	612	160		0	1.29
R	11	A	-	1	26.5	5.7	623	150.5	a	1	1.31
R	12	D	113.5	6	0	12.6	569	152	a	1	0.95
R	13	B	113.5	2	0	9.2	631	152.5	d	0	2.35
R	14	B	105	2	10.3	8.4	605	161		1	1.08
R	15	B	115.5	7	0	14.9	565	152		0	0.98
R	16	C	103.5	8	0	11.5	604	158	b	1	1.56
Mean R-group			109.7		6.5	10.7	599	155.2		5*	1.34

¹X-ray performed in November as 1-year-olds on tarsal, metacarpal and metatarsal joints, horses with defects validated to similar severity received the same letter and were separated between the groups. * = Total number of remarks.
Information used to allocate horses in to 2 groups (control: C and reduced: R). Groups were balanced to be as equal as possible with respect to breeder (A-D), breeding index (average of breeding index of parents, − if no breeding index for parents available), sire, part of French ancestors in pedigree, inbreeding coefficient, age (days in the 1^st of January as 2-year-olds), height at withers (cm), x-ray findings¹ _, conformation remarks (0 = no serious remark, 1–2 = remarks) and quote of percentage of type IIA / type IIB muscle fibers in musculus gluteus medius.

ISSN: 1751-0147