Feeding Forages to the Growing Horse

Introduction

Good quality forage fed in appropriate amounts can supply a large percentage of a horse's daily nutrient requirements. However, for the young horse it is commonly suggested that the forage portion of the diet make up a smaller portion (30-40%) and that the concentrate feed be the main supplier of nutrients. In Western Canada there is an abundance of high quality forage available to horse owners, and it is reasonable to use this forage in such a way as to maximize its contribution in meeting the nutrient requirements of the horses being fed.

With this in mind, the Horse Industry Branch over the past 18 years has conducted a number of research projects that looked at the use of forage in horse diets. This paper is a summary of some of those research projects.

Feeding High Forage or High Concentrate Diets

The level of forage in the diets for young horses as previously mentioned is a point of contention. NRC 1989 suggests that weanling horses should be fed diets that are 30% forage. The first research project looked at the effect of a high forage diet on the growth of weanlings. In this project, 90 weanlings were fed diets that were 70% alfalfa cubes and 30% concentrate or 30% alfalfa cubes and 70% concentrate with the 70% concentrate diets being either oat or barley based. The weanlings were fed to appetite for 200 days. The results are reported in Table 1.

Table 1: Growth performance of weanling horses fed high forage or high concentrate diets

Treatment	# of horses	ADG3 kg/day	ADMI4 kg/day	Feed efficiency5
70% alfalfa cube 30% concentrate	28	0.89a	8.36a	9.39c
70% concentrate 30% alfalfa cube1	28	0.96a	7.98a	8.31b
70% concentrate 30% alfalfa cube2	27	0.96a	7.95a	8.28b
1 The 70% concentrate was an oat-based concentrate mixture. 2 The 70% concentrate was a barley-based concentrate mixture. 3 ADG = Average Daily Gain. 4 ADMI = Average Dry Matter Intake. 5 Feed efficiency is the feed to gain ratio. abc means within a column not sharing a common superscript are different (P<0.05).

While the horses fed the high forage diet ate slightly more feed per day than the high concentrate fed horses (differences were not significant) but the daily growth rates were not different among any of the treatment groups. The only difference in this project was the feed to gain ratios were better for the horses fed the high concentrate diets. These results suggest that using a high quality forage like alfalfa cubes will provide an adequate intake of nutrients to meet the growth requirements for weanling horses. A result of interest was the lack of differences in either the oat based or the barley based diets for any of the parameters measured. Horse owners could consider using barley in the grain mixes their horses when oats were unavailable or expensive.

Meeting Protein and Lysine Requirements with Forages

Another concern that has been raised is the availability of the protein in alfalfa forage to the horse. It has been reported that even though high protein alfalfa hay (17% protein or greater) is used, it must be fed with a source of supplemental protein (soybean meal) in order to meet the young horse's protein requirement because of reduced availability of protein in the forage. In a feeding trial, 60 weanling fillies were fed diets that were 60% alfalfa cubes and 40% concentrate. Diet 1 (NRC 100) met NRC 1989 requirements for protein and lysine based on alfalfa cubes and the grain concentrate with no added protein supplementation. The other 2 diets had 115% of the requirements for protein and lysine (NRC 115) or 130% of the requirement for protein and lysine (NRC 130). All three diets provided similar intakes of energy and minerals for rapid growth and were fed at 3% of body weight. The hypothesis for this trial was if the protein in the forage was unavailable the horses fed the diets with supplemental protein (115 or 130% NRC 1989) should have a growth response and grow at a faster rate. Table 2 shows the results of this experiment.

Table 2. Growth performance of weanling fillies fed diets containing graded levels of protein in alfalfa cube based diets

Treatmenta	# of horses	ADG1 kg/day	DMI2 kg/day	Feed:Gain Ratio	BCS3
100% NRC	20	0.72	6.73	9.32	5.43
115% NRC	20	0.70	6.66	10.0	5.20
130% NRC	20	0.71	6.72	9.84	5.45
a Treatments were 100%, 115% or 130% of the NRC requirement of protein and lysine for rapidly growing foals. 1 ADG = Average Daily Gain. 2 DMI = Dry Matter Intake. 3 BCS = Body Condition Score - based on the 1-9 system of Henneke et al. (1983).

There were no differences in growth rate, dry matter intake or feed efficiency between the three dietary treatments. The fillies in this trial were body condition scored at the end of the trial to determine level of body fatness. The lack of difference in body condition score would indicate that the growth exhibited by each group was similar and none of the horses were simply getting fat. This would suggest that the alfalfa cube based diet did provide enough protein for the horses to have above average growth rate and that any other increases in daily gain would have required more energy in the diet not more protein.

In a follow up to this trial, two digestibility studies were conducted to determine the prececal protein availability of alfalfa forage. These trials were done using ponies that were cannulated in the distal ileum. That is the end of the small intestine just before the cecum. This procedure allowed for the determination of protein digestibility in the small intestine. This is important because 60-70% of all protein digested by the horse is digested in the small intestine.

In the first trial the ponies were fed the following diets: 100% alfalfa cubes or one of 3 mixed diets containing 60% alfalfa cubes and 40% concentrate. The mixed diets provided protein and lysine at 100% , 115% or 130% of the NRC 1989 requirements. The results of this trial noted that 47% of the protein in the alfalfa cubes was digested in the small intestine. This is similar to the results published by Dr. H.F. Hintz in the 1970's. The diets containing the 40% concentrate had greater prececal protein and lysine digestibilities than the alfalfa cubes alone as would be expected. As the level of soybean meal increased in the concentrate mixes so did the prececal digestibility of both the protein and the lysine. While this was expected the significant finding of this trial is that the availability of the protein in the alfalfa forage is as high as it is. Therefore the protein supplied in a high quality forage such as the alfalfa cubes used in this trial can have a role in meeting a significant portion of the horse's protein requirement.

In a second experiment with the cannulated ponies, the effect of the level of forage in the diet on prececal protein digestibility was determined. In this trial, ponies were fed diets containing 100%, 75%, 50%, or 25% alfalfa cubes. As the level of concentrate in the diet increased up to 50%, the prececal protein digestibility also increased. However, at 75% concentrate the prececal protein digestibility deceased. This suggests that there is an effect of high concentrate intakes on nutrient digestibility. The conclusion drawn in this experiment was that the higher levels of concentrate (75%) caused a more rapid rate of passage of digesta through the tract which reduced the opportunity for digestion and absorption of the dietary protein in the small intestine. It appears from this data that in feeding programs where the level of concentrate exceeds 50% there may be potential reductions in nutrient digestibility.

Feeding High Quality or Low Quality Forages

The previously described projects used a high quality alfalfa cube as the forage source and using a high quality forage gave good results either improved daily gains or feed efficiencies. What affect would the use of a lower quality forage have on growth performance of young horses. In certain situations forages with lower nutrient levels are less expensive to purchase but is this true economy or cheap hay? A trial was conducted to compare a 100% alfalfa cube (high quality) to a cube that was 70% alfalfa and 30% cereal straw (medium quality) when fed to long yearling horses. The growth performance of both groups of long yearlings is found in Table 3.

Table 3. Daily gain, dry matter intake and feed:gain ratio of long yearling horses fed 100% alfalfa cube or 70% alfalfa/30% cereal straw cube based diets.

Treatmenta	# of horses	ADG1 kg/day	DMI2 kg/day	Feed:Gain Ratio
100% Alfalfa cubes	30	0.82a	10.88	14.9c
70% alfalfa -30% cereal straw cubes	31	0.67b	10.72	20.0d
1 ADG = Average Daily Gain. 2 DMI = Dry Matter Intake. ab Means not sharing a common superscript in the same column are different (P<0.05) cd Means not sharing a common superscript in the same column are different (P<0.01)

The horses fed the 100% alfalfa cube diets had greater growth rates and better feed efficiencies than the horses fed the diets based on the lower quality cubes. High quality feed is more economical as it takes less feed to have the same results than when a poorer quality feed is used.

Feeding Hay in a Feeder or On the Ground

How many times have you seen horses fed on the ground? It is a common practice that in addition to increasing the potential for parasite infection in your horses, there is a tremendous potential for feed to be wasted. How much feed is wasted is not well known so a project was conducted to determine the effect of feeding horses hay on the ground vs. in a hay feeder. For this trial, 60 yearling colts were fed long stem alfalfa hay and their growth rates and efficiency of feed utilization recorded. The results are shown in Table 4.

Table 4. Average daily gain and feed:gain ratio for yearling horses fed alfalfa hay on the ground or in a suitable feeder

Treatment	# of horses	ADG1 kg/day	Feed:Gain Ratio
In a Feeder	30	0.62a	9.85c
On the Ground	30	0.50b	11.67d
1ADG = Average Daily Gain. abMeans not sharing a common superscript in the same column are different (P<0.001) cdMeans not sharing a common superscript in the same column are different (P<0.02)

The horses fed the hay in a hay feeder had better growth rates and better feed utilization than the horses fed the same hay on the ground. The difference in feed utilization results in a feed saving of 18% by not feeding on the ground. The hay feeder in this trial was simply a box that was 2 ft high by 4 ft wide and 6 ft long. It accommodated 5 yearlings at one time and held the daily feed allotment for the 5 horses with minimal spillage. The savings in feed cost by using a simple feeder can add up rapidly.

Creep Feeding

The last project to be discussed is not a forage project but a project that looked at the use of creep feeding and its affect on the growth of suckling foals. The horse industry has not accepted the practice of creep feeding because of concerns over horses growing too fast and suffering from development problems. However there are potential problems with the stress of weaning which could be reduced if the foals are accustomed to eating dry feed prior to weaning. In this project the objectives were to evaluate the growth response of foals that were creep fed for at least 45 days before weaning and also to look at the affect of weaning on post weaning weight loss. An additional part of the project was to look at the effect of the level of protein in the creep ration on the parameters measured. The project used 108 mare foal pairs which were randomly divided into 12 breeding herds. All the horses in the treatment groups were of stock horse type. There were 4 groups of mares and foals on each treatment. The treatments were No Creep, a 13% Creep Ration and a 17% Creep Ration. The creep fed foals were fed daily at 1 lb of feed per month of age per day. The feeding period lasted for 53 days. The results are found in Table 5.

Table 5. Foal body weight, average daily gain (ADG), daily feed intake and the 24 hour post weaning weight loss for stock horse foals.

	No Creep Feed	13% Protein Creep Feed	17% Protein Creep Feed
Number of foals	38	30	36
Body weight (kg)
Initial	137	137	144
Final	192	199	204
ADG1 (kg/day)	1.06b	1.20a	1.14a
Creep feed intake (kg/head/day)	0	0.84	0.56
24-hr Post-weaning Weight Loss (kg)	9.4	6.8	8.1
1ADG = Average Daily Gain. abMeans not sharing a common superscript in the same row are different (P<0.05)

The foals that received creep feed gained more weight than the non-creep fed foals. While the differences are small they are significant. However the differences between the two creep fed groups were not significant. The foals used in this study were extensively managed in that they lived in large pastures and did not spend a great deal of time near the creep feeder. This resulted in feed intakes that were below the expected levels. The reduced feed intakes however did provide enough additional nutrients for additional growth recorded.

The creep fed foals had a tendency for reduced weight loss during the first 24 hours post weaning. It appeared that because the foals were accustomed to eating dry feed they continued to eat after weaning instead of going into a post weaning slump. The reduction of stress post weaning is a major benefit of creep feeding.

Conclusions

The research presented here can be applied directly to on farm situations. It does not matter that you are not using alfalfa cubes but horse owners need to feed the best quality hay they can purchase. Instead of feeding on the ground, save some of your feed dollars and get a feeder. Remember that the forage you use in the feeding programs for you horses is the most important component of your feeding program regardless of the class of horse you are feeding.

Acknowledgments
The Horse Industry Branch of Alberta Agriculture Food and Rural Development gratefully acknowledges the support of the following people:
Mr. Claude Bouvry - Bouvry Exports, Fort McLeod, Alberta
Mr. Henry Braam - Champion Hay Processors, Didsbury, Alberta
Mr. Bob Stillborn - Lakeside Research, Brooks, Alberta
Tracy and Sandy Watson - Wolf Creek Ranch - Alder Flats, Alberta
Mr. Norm Luba - NAERIC - Louisville, Kentucky

About the Author

Dr. Bob Coleman was formerly an Equine Nutritionist and Horse Specialist with Alberta Agriculture Food and Rural Development. Dr. Coleman is currently the Equine Extension Specialist with the Department of Animal Sciences at the University of Kentucky.

This information appeared in "More Than Ever Horses Need Forages", which was presented at, and appears in the Proceedings of, the 1999 Alberta Horse Breeders and Owners Conference.

Bob Coleman, Ph.D. Extension Horse Specialist University of Kentucky