Effect of ambient temperature and daylength on hoof growth in sheep

Abstract

In Southdown sheep, which grazed and were fed during the day to maintain body weight and were housed at night, there was no clear effect of ambient temperature on hoof growth. In these sheep, equatorial or reversed photoperiods did not influence hoof growth.In an indoor experiment over 19 months on Merino sheep, with natural light and temperature, fleece accumulated normally between spring shearings. Hoof growth in winter was low at a low level of nutrition but was not reduced in sheep at a higher nutritional level. It fell dramatically at both levels of nutrition in the first month after shearing.Hoof growth was measured in Merino and Southdown sheep exposed to equatorial daylength in two climate-room experiments in which ambient temperature was varied. Fleece length was kept short and nearly constant by clipping. Hoof growth was greatly reduced by low temperature. At a given ambient temperature it was more rapid when ambient temperature was rising from month to month than when it was falling. The low hoof growth observed in the cold was associated with low hoof temperature and there was some evidence suggestive of reduced blood flow to the skin of the lower legs.These temperature effects would complicate the use of hoof growth as an index of nutrition. INTRODUCTIONfrom 8 Merinos at two nutritional levels. A shortIt is possible that hoof growth rate could prove * e r a l experiment (Exp. 3) with 6 Merinos and 6 a useful index of nutritional status (Anon., 1960; Southdowns in a climate room, with equatorial day- Godwin, 1962;Wheeler, 1966) if more were known ^g** 1 a n d temperatures altered each month, preabout the environmental factors controlling it -in c e d e d a n ^-month study (Exp. 4) with 8 Merinos particular, the effects of temperature and any l n thesame room, but with temperature held conannual rhythm. The effects on hoof growth of s t a n t f o r P e n o d s o f ^ m o n t h sdifferent ambient temperatures and of three photoDetails of experiments periodic treatments were studied in multiple objec-Experiment 1 tive experiments, which were also concerned with the effects of temperature and nutrition on wool H o o f S r o w * h r a t f w e r e m e a^e d in this experigrowth, and with breeding activity. m e n t P n m a r i l y *> determine whether there was an annual rhythm in hoof growth that was controlled MATFPTAT S A*m MFTTTOT^ b y d^W^-I f daylength proved to be without MATERIALS AND METHODS e f f e c t > a s e c o n d a r y o b j e c t i v e was to gain informaDetails of four experiments are presented. In tion on the effect of ambient temperature on hoof Exp. 1, 21 Southdown ewes, housed at night and growth in sheep maintained at a nearly constant exposed to various photoperiodic treatments, were live weight and with normally increasing fleece used. In Exp. 2 data were collected over 19 months length.

Dynamics and impact of footrot and climate on hoof horn length in 50 ewes from one farm over a period of 10 months

“…Thus, sheep hoof horn is affected by floor type; in 21 healthy yearling ewes at pasture, hoof horn growth rate was 3.3 mm/month ( Shelton et al., 2012 ) while in five lambs and five ewes on concrete, hoof horn growth rates were 13.2 mm/month and 8.7 mm/month, respectively ( Dekker et al., 2005 ). It is also affected by temperature; Wheeler et al. (1972) reported growth rates of 0.7–6.0 mm/month in four groups of 8–21 sheep, and that sheep kept in low ambient temperatures had a slower hoof horn growth rate.…”

Measurement and error of hoof horn growth rate in sheep

“…Hoof horn growth rate is influenced by the age (Tranter and Morris., 1992;Dekker et al, 2005) and genetics (Quintanilla et al, 2006) of an animal together with its diet; with vitamins such as biotin (Buffa et al, 1992), minerals such as zinc (Smith et al, 1999) and increased energy intake (Butler and Hintz., 1977) enhancing the rate of growth. Environmental factors that influence hoof growth rate include abrasiveness of the floor surface (Hahn et al, 1986) and ambient temperature (Wheeler et al, 1972).…”

“…To date there have been only two studies estimating hoof horn growth rates in sheep (Wheeler et al, 1972;Dekker et al, 2005). Dekker et al, (2005) measured the growth of hoof horn in five healthy newborn lambs and five healthy ewes.…”

“…To date there have been only two studies estimating hoof horn growth rates in sheep (Wheeler et al 1972; Dekker et al 2005). Dekker et al .…”

“…There was no difference between the growth rate in front and hind feet. Wheeler et al (1972) studied hoof horn growth rate under varying temperatures and day length. There was no association between day length and growth rate, but sheep kept in low ambient temperatures had a lower hoof horn growth rate.…”