Nutrition
Is spring grass the best grass for horses?
Briony Witherow BSc MSc RNutr. PGCERT FHEA, explains why careful nutritional management is vital as the seasons change
Although it’s still early in the new year, it doesn’t hurt to start planning how you will manage your horse as the warmer weather approaches. The end of March – just a few weeks away now – typically signals an increase in grass growth that we know as the ‘spring flush’. It is this rapid growth, often coupled with increased access to pasture, that makes this a challenging period when it comes to managing our horses.
What challenges does spring present to the horse’s gut?
In spring, the equine gut is confronted with not only changes in management but also forage type, and it is the combination and speed of these modifications that typically gives rise to problems. The crux of the challenge upon which success or failiure can often hinge, is the period over which the forage type is changed. While after what seems like a long winter, it is more than tempting to jump at the chance at providing as much turnout as possible, as soon as it’s made available however, a more measured approach is warranted.
The underlying reason being that while both hay or haylage and grass are ultimately the same ‘ingredient’; the nutrients offered and fundamentally, how much moisture they contain (dry matter), are vastly different¹. It is these differences that the gut struggles to cope with, particularly where introduction is rapid¹.
A good way of thinking of the different forms of forage and how the format impacts nutrition, is to think of grass as the equivelnt of a fresh banana and hay as dried bannana chips. They are both made from the same ingredient (banana or grass) BUT crucially, one has been dehydrated and the other is in its ‘fresh’ form. The fresh form however, also contains all the moisture which essentially dilutes the nutrients – meaning that 1kg of fresh bannana would provide less nutrients (and significantly more moisture!) than 1kg of dried bannana chips. The same goes for grass versus hay. While grass tends to be more palatable, generally more nutritious² and is likely to be consumed in greater quantities, the additional moisture (water consumed) and lower levels of fibre in comparison to a hay based diet (due to nutrients being diluted), culminate – in the best case scenario – in loose droppings and the worst case, colic.
Fibre is fundamental in regulating passage through the gut, a lack of this control coupled with the potential for an ill-adapted gut due to rapid changes, and it is easy to see why loose manure is such a common sight at this time of year. The other challenge that lurks for our good doers is that unregulated pasture intake is very likely to exceed most leisure horse (and even some performance horse’s) energy and therefore, calorie requirements² ³ adding an extra layer of complication for those dealing with good doers.
How can management help?
Preparation is key and changes should be made in steps – only make one change at a time wherever possible. If both the hard feed and forage require change, change the forage first – then, you can think about changing the hard feed. This lessens the risk of over-providing energy (calories) (through changing both feeds at the same time) while simultaneously helping the gut.
Forage changes should be very gradual, particularly where the horse has shown previous evidence of equine digestive disruption (loose droppings or colic). Where possible, forage changes should be made over 3 to 4 weeks¹ – this includes turnout. Turnout introduction should start at 20-30 minutes per day, gradually building up to the desired full turnout routine. While this may seem impractical, taking some care at this stage can help to avoid setbacks later on.
Where a gradual increase in grazing time is not possible, practices such as offering hay/haylage in the field or bringing the horse in for a few hours a day for hay/haylage will help to increase fibre and dry matter intake, thereby helping to normalise passage rate and gut function. During this transitional period, monitor your horse’s droppings and use this as a guide as to how well their digestive system is coping – if they turn loose at any point, alter your management by reducing grazing time slightly and once droppings have returned to normal, resume your increase in grazing time, but more slowly.
For horses who find a change in routine or diet difficult to manage (potentially suffering recurrent colic or persistent loose droppings even when the change is gradual), consider using a digestive supplement to support the system through periods of change ⁴ ⁵. Monitor weight and condition regularly during this period (ideally every week) to look for any early signs of weight gain. Where possible, remember to weigh tape and body condition score at the same time of day each week, as measurements can fluctuate with gut fill⁶ ⁷ ⁸. Remember while grass provides ample energy and protein (often meeting requirements during the grass growing season² ³, it is often lacking in micronutrients (in particular minerals like zinc and copper)² ⁹. As such, to ensure a balanced diet ensure that your horse recieves (at a minimum) either a broad spectrum vitamin and mineral supplement or a balancer.
Spring time considerations for the good doer
Wherever possible, in the ideal world, our good doers would be entering spring in lean body condition (2 on a 5-point scale or 4 on a 9-point scale¹⁰ ¹¹) providing a buffer to allow for natural weight gain during the grass growing season⁶. However, if winter weight loss goals didn’t quite become reality or your horse is part way there but still not as lean as you’d like, spring pasture management is crucial.
The first thing to be aware of is there is ALWAYS more grass available than we think. Setting up your own ‘test plot’ can be a useful guide especially at this time of year, and can provide a handy indication of when additional pasture restrictions may need to be employed. All you need to do is find a small area of grass (ideally out of reach of any horses but in the vicinity of the field with similar environemntal conditions etc.), mark the location so that you can check in and each day and monitor grass growth. Using this method, albiet slightly crude and simplistic, you will quickly get a feel for how much grass is coming through and therefore, how much is likely being consumed in the field.
When it comes to what grazing restrictions can be applied, there are various options and your particular set up or faclites and indivudal horse will largely dictate which is most suitable and feasible.
References
- Harris, P.A., Ellis, A.D., Fradinho, M.J., Jansson, A., Julliand, V., Luthersson, N., Santos, A.S., Vervuert, I. (2017) Review: Feeding conserved forage to horses: recent advances and recommendations. Animal: An International Journal of Animal Science, 11 (6): 958-967
- Equi-analytical laboratories. (2020) Common feed Profiles. [Online]. [Accessed 22nd February 2021]. Available from: https://equi-analytical.com/common-feed-profiles/
- NRC, (2007) Nutrient requirements of Horses, Sixth edition. National Academies Press: Washington, DC.
- Morgan, L.M., Coverdale, J.A., Froetschel, M.A. and Yoon, I. (2007) Effect of yeast culture supplementation on digestibility of varying forage quality in mature horses. Journal of Equine Veterinary Science. 27(6): 260-265.
- Jouany, J.-P., Medina, B., Bertin, G., and Julliand, V. (2009) Effect of live yeast culture supplementation on hindgut microbial communities and their polysaccharidase and glycoside hydrolase activities in horses fed a high-fiber or high-starch diet. Journal of Animal Science, 87 (9): 2844-2852.
- Dugdale, A.H., Curtis, G., Cripps, P.J., Harris, P.A., and Argo, C.M. (2010) Effects of season and body condition on appetite, body mass and body composition in ad libitum fed pony mares. Veterinary Journal, 42 (7): 600-610
- Ellis, J.M. and Hollands, T. (1998) Accuracy of different methods of estimating the weight of horses. Veterinary Record, 143: 335-336
- Hintz, H., F. (2002) How much does that horse weigh? Journal of Equine Veterinary Science, 22 (8): 362
- Kuusela, E. (2006) Annual and seasonal changes in mineral contents (Ca, Mg, P, K and Na) of grazed clover-grass mixtures in organic farming. Agricultural and Food Science, 15 (1): 23-34.
- Henneke, D.R., Potter, G.D., Kreider, J.L., and Yeates, B.F. (1983) Relationship between condition score, physical measurements and body fat percentages in mares. Equine Veterinary Journal, 15:371-372
- Carroll, C.L., and Huntington, P.J. (1988) Body condition scoring and weight estimation of horses. Equine Veterinary Journal, 20: 41-45
