Becoming too thin?

I have an extremely athletic horse that got moved to our barn recently. There are 2 mares around him all day and since then, he seems to have gotten a little skinnier. We feed him the same amount he was fed at his other barn. He is 100% healthy with no parasites. Is it the excitment of the mares? Should I just feed him more food?

Are all 3 horses fed separately? If not, the new horse may be getting pushed off his feed by one of the mares.
If they are fed separately, I'd say it's stress from the move. Give him time to settle in and give him a little extra hay.

They are fed seperatly. BTW he thinks he's a stud so we are guessing that he is excited by the girls around. Our temporary solution is to feed him the senior feed that we give the older horses. The senior feed has more calories than the normal feed. Idk if this is the best solution but I don't want his ribs to get any more prominent than they all ready are. We don't need any one thinking we neglect our horse.

Watch him to see if he's pacing. Sometimes a move will stress a horse and they can lose some weight. If his behavior doesn't improve and he continues to lose weight (or not gain if you increase his feed/hay), then you may need to move him farther away from the girls.

How long ago did he move there? It could be he is just getting used to his surroundings

Is it possible he's not underweight, just fit and you're not used to seeing this type of build? Also what are you feeding him & what feed was he on & how frequently & small are the feeds? You say 'senior feed' & if this includes more sugar/starch, this could actually be contributing to his weightloss, rather than putting more on. Especially if it's fed infrequently &/or in large meals.

Him along with the horses that work harder have grain w/ 1 pump of lubrisyn (joint lubricant) and hay 2 times daily. Our 26 year old mare has the senior feed to help keep her weight on (you know because some older horses have a harder time keeping on weight). The senior feed has more calories than normal feed. He may have a different build. He is just tall enough to be a horse and could probably classify as a pony so he probably shouldn't be too big. I just I don't know, are you suppost to see the spine at the base of the neck? Should ribs be visable? Maybe sometime in the next couple of days I can get photos of him. And you guys could give an opinion.

As others have said, there may be other reasons - stress for eg - that have caused him to lose weight, so he may be getting adequate nutrition, just needs to settle in. Spine showing at the base of the neck - I assume you don't mean wither - indicates that he *may* be underweight, but that he may also lack muscle &/or be atrophied in that area. A bit of rib showing is fine generally & far preferable health-wise than being unable to find them!<G> But the above are both generalisations, and it depends what the whole horse is like, not just a couple of spots, as they're all individual, just like us - you can actually see my ribs clearly, but I'm overweight, for eg!<GG> Of course I don't know whether your horse is actually a good weight or not, but just questioning it, as overweight & obese horses are such an epidemic that many people just fail to recognise & many a time I've heard healthy looking horses pronounced as needing fattening, and there are so many health probs associated with overweight horses.....

Regarding grain, seniors & senior feed, yes, extra calories are sometimes necessary, but it's often IR probs, imbalanced nutrition or teeth & gut function problems that lead to oldie's weightloss, and healthy horses shouldn't generally need extra calories than 'maintenance' unless they're in hard physical training. Therefore calories - especially carbs - is not generally the answer, and high-carb feeds are more likely to effect oldies(google Cushings, for eg), but still commonly cause various health probs in youngsters too.

I urge you to get onto an equine nutritionist and look into this subject, because I don't want anyone just taking my word for it, any more than I want people continuing to just feed this type of stuff because it's traditional. FeedXL.com is my service of choice, that is fantastic help and value.

No, you shouldn't be able to see ribs. I would try increasing his hay ration by 50% and add a fat supplenment to his diet like flax or rice bran (1/2 cup a day to start). Also make sure he's up to date on deworming and his teeth have been floated or at least checked by a vet in the last 12 months.

The stress of a move can cause horses to drop weight. You just need to add some more food to his diet and be patient. Things usually level out after a few weeks, once the horse settles in.

I would be curious to know what sort of behavior he's exhibiting in his stall when the mares are in there. How many hours a day does he spend in his stall? I am a bit suspicious of weight loss being caused by being around mares. If it's not worms, it could be stress or teeth. I would also consider some simpler explanations such as---is he being ridden more often or harder, does he spend more or less time out in the pasture than before, or is there less grass at your facility than his old one? You mentioned he gets the same amount of feed as his previous barn, but is it the same type? Every brand and type of grain have different amounts of calories so you can't always feed the same amount of two different grains and expect the amount of calories to be the same.