Housing and management of horses in Nordic and Baltic climate
NJF seminar nr. 437, 6.-7. June 2011, Iceland
25. Outdoor feeding management and needs of horses – an overview
Markku Saastamoinen
Agrifood Research Finland, Animal Production Research, Equines, Opistontie 10 a 1, FI32100 Ypäjä, Finland.
Introduction
Feeding horses outdoors in winter and cold climate presents a challenge to horse owners and stable
managers. Low temperatures, harsh winds and rain, snow and ice all contribute to the increasing
nutrient requirements a horse has to keep themselves warm and maintain their body weight. The
most challenging is to feed young growing horses – the largest group of horses kept in loose stables
- the focus being on the energy demands of the horse. When the climatic energy demands are taken
into account, also the weanling horses can maintain their body condition and proper growth (Autio,
2008).
Although horses are fed in groups, their individual needs have to be considered applying individual
feeding. Some studies show both breed and individual differences in the digestibility of nutrients or
energy demands among some horse breeds used in the Nordic countries (Saastamoinen, 1993;
Ragnarsson, 2009; Jensen et al., 2010). There are also some studies found a tendency toward higher
digestibility in ponies than in horses. Some individuals are so called “easy keepers” accumulating
fat easily in their body. In addition, the amount of voluntary exercise of horses varies resulting
different energy needs and feeding levels.
To keep horses health and to guarantee their wellbeing, it is important to take care of the hygienic
quality of the feeds and feeding facilities in the paddocks or loose stables. Poor hygienic quality of
feeds and feeding may cause sever problems both in gastro-intestinal tract and airways of the horse.
Feeds stored and fed outside alter poor climatic conditions, and may be source of many harmful
micro-organisms.
Eating and feeding is also part of the social life of the horses in paddocks and the loose housing
systems. The horse can be characterised as a ‘herd’, ‘nomadic’ and ‘flight-animal’, which spends
about 60% of its daily behaviour on voluntary food intake (Duncan, 1980; Vulink, 2001; Davidson,
1999).
Effect of the cold weather
Young horses kept in outdoor paddocks or loose stables require additional energy for heat
production and play. When horses are kept in harsh or cold weather below the lower critical
temperature (LCT) - determined to different horse groups based on their age, type and breed additional demands for heat production should be taken into account to avoid weight loss (Gordon
et al., 2009). Variation of LCT for different age groups is presented by Cymbaluk (1994).
The amount of the extra energy depends on the ambient temperature and management system (type
of shelter etc.) and age/weight gain of the horse as well as on group dynamics. The thermoneutral
zone has been defined as between 0-5ºC and 20-25ºC in horses (Morgan, 1997). Langlois (1994)
and Cymbaluk (1994) have reviewed several studies dealing with thermoregulation and cold
adaptation of horses.
Cymbaluk (1990) recommend 0.7-1.3 % increase in maintenance DE (+ requirement for weight
gain) for each degree below 0oC for thoroughbred type growing horses. Autio et al. (2007) studied
weanling foals (various breeds) in cold loose housing system founding the LCT being between -9
and -16 0C, and recommend 1.8 – 0.2 % increase to the ME recommendations of weanling foals
from November to January. McBride et al. (1985) reported that adult horses (500-kg horse) should
be given added energy of 1.5 MJ ME per each degree below LCT of -15 oC, meaning 2.5 % in DE.
Consequently, the additional energy requirements for a growing thoroughbred horse (18-36 months)
may vary between 0.7% more DE per degree below 0ºC and up to 2.5% per degree below -11ºC. It
should be noticed, that energy requirements for exercise are unlikely to be affected in low
temperatures (Ott et al., 2005).
Autio (2008) reported that climatic energy demand gradually decreased as the horses acclimatized
to the cold housing environment. In addition, the decreased growth during aging of the foal and
young horse (Saastamoinen, 1990b) decreases the energy expenditure for growth. Same time the
ambient temperature is increasing from winter to spring, causing decline in the need of energy to
heat production. These reductions in the energy requirements are necessary to take into account to
avoid fattening of the horses.
In some cases the horses can spare energy for heat production by decreasing the amount of
voluntary exercise, when, in fact, their energy intake may decrease, but this may lead to lower
weight gain, as reported by Cymbaluk and Christison (1989). The studies above were conducted
with yearlings, and the results can not be applied to older horses.
In the Swedish (SLU, 2004) and Finnish (MTT, 2010) recommendations, following additional
energy amounts are recommended due to cold weather: Weaned foal + 1,4 %/degree below 0
oC, young horse + 1,4 %/degree below -11 oC, adult horse + 2,7 %/degree below -15 oC. The
additional feeding should be adjusted for the type of the shelter or the loose stable (isolated,
nonisolated)
and the time kept out. In addition, if blankets are used, the need for heat production may
be reduced.
Those recommendations above are more indicative, and it is important to take account individual
differences and needs. There are variation between the types and breeds of the horses in coat
development, and thus in cold resistance, some ponies and cold-blooded horses being most suitable
for loose housing (Autio, 2008). Recent studies show also moderate heritability estimates for body
condition score (BCS), i.e. accumulation of fat under skin, which means a clear hereditary
background of this character (Schrurink et al., 2010; Mantovani et al., 2010). In addition, growing
males tended to be leaner and lighter than females, who accumulate more body fat compared to
males (Saastamoinen, 1990b). Consequently, all these factors are affecting cold resistance of an
individual horse, and should be taken into account. It is important to control the BCS regularly, e.g.
every 30 days.
Further, concerning growing horses, there are individual differences in their growth rate
(Saastamoinen, 1990a, b). This has also to be considered when assessing the energy requirements of
the horse. Especially measures of physical condition (BW, chest width) showed large variation in
horses still growing (Saastamoinen, 1990b).
Feeding management
Horses coming to group conditions and loose housing systems may be stressed if they originate
from many different stables and managements. This stress may decrease their feed intake resulting
negative energy balance. In addition, they are maybe not acclimatized to the cold environment. This
is most evident in weanling foals, but challenges the stable staff concerning all horses, to carefully
plan and carry out the feeding.
To provide optimum energy for heat production, good quality hay/haylage and/or oats are the best
choice, because digestion of fibre produces heat. Hay and haylage can be substituted by hay cubes.
Beet pulp can also be a beneficial source of fibre. It is important to check the teeth of the horse and
floated them if necessary prior to winter feeding, to improve the utilization of the fibrous feed.
However, because of the changes in the energy requirements described earlier, it is necessary that
the amount of feeds is restricted and ad libitum feeding should not be applied. Using of automatic
feeders helps to assess the daily feeding according to the needs of individual horses. If no automatic
feeders are used, it is necessary to arrange enough space for each horse in the feeding stations to
ensure adequate feed intake to all horses.
It is necessary to know the nutritional quality of the feeds to adjust the nutrition according to the
needs of the horse. In addition of that, as said above, it is reasonable to control and restrict, if
necessary, the feed intake of the horse. Horses can select the most digestible parts of the feed, and
voluntary intake of the feed decreases with declining forage quality (Eduard et al., 2008). However,
some horses may compensate for the low nutritional value of the forages by increasing intake. But
horses have certain capacity of feed intake, and it is also known that intake of large amounts of
poorly digested feed may decrease the total digestibility of the diet, which may result in declined
energy intake. However, in their study Eduard et al. (2008) concluded that the horses could meet
their maintenance requirements.
Effects on health and welfare
To avoid the horses become overweight, it is necessary to control and restrict their feed intake.
Overweight and obesity are related to laminitis and insulin resistance in horses, and overweight is
also detrimental to the legs and joints of the growing horse. Dietary restriction and manipulation can
be used to decrease the overweight and improve the welfare of the horse (Gordon, et al., 2009;
Dugdale et al., 2010). Dugdale et al. (2010) found that with decreased feeding activity, time spent
in play increased. Gordon et al. (2009) observed that also the control horses without any restriction
lost their weight due to the harsh weather conditions, because they possible used more energy for
heat production. This means too, that cold weather conditions can be utilised in purpose to decrease
the overweight.
To maintain a healthy digestive tract and good welfare, an adequate supply of structural fibre is
required – a level of at least 1.2% of BW as forage feed (DM) is recommended with a daily DM
intake of 2.5% of BW when stabled. In terms of feed intake behaviour and requirements for
chewing it is the lack of fibre, which also contributes to the nutrient imbalances. This lack of fibre
intake may be of greater significance than the high intake of concentrates (Ellis and Saastamoinen,
2008). Eating the bedding straw is a time-consuming activity as well, and may help compensate the
lack of bulk in the diet. McGreevy et al. (1995) reported that the use of any bedding material other
than straw was associated with a higher incidence of stereotypic activities.
Poor hygienic quality of forage is always a risk to the horses’ health. Causes of chronic airway
disease and such symptoms usually involve exposure to excessive concentrations of e.g. airborne
dusts, moulds, bacteria and endotoxins originating from beddings and feeds (Derksen, 1991).
Mycotoxins have many detrimental effects on horses, e.g. on growth and reproductive function of
mares (e.g. Aurich et al., 2006). Storing and feeding the forages are important factors affecting their
hygienic quality. Automation of feeding and good feeding facilities and equipments may help in
avoiding contamination of bacteria and moulds.
Geophagia or soil eating has been observed to be quite common in horses related with boredom and
nutritional deficiencies (McGreevy et al., 2001). Ellis et al. (2006) reported a significant increase in
geophagia and bedding eating (wood chippings) in 2½-year-old warmblood horses, which had been
stabled on a high concentrate diet with a medium-heavy workload. Increasing of feeding and
physical activity is necessary to avoid boring, and, thus the geophagia of the horse.
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