# Crop Milk



## Snowbird (Jun 24, 2004)

In pigeons and doves the crop of both sexes produces ‘crop milk’ for feeding nestlings. The production of crop milk has many similarities with lactation in mammals. Brooding stimulates prolactin secretion, which triggers differentiation of the crop epithelium around the six day of incubation (the superficial layer of cells lining the alimentary canal and all its appendages, all glands and their ducts, blood vessels and lymphatic, serous cavities, etc.). By the thirteenth day, the epithelium thickens considerably and becomes rich in blood vessels, making the crop lining reddish in color. The epithelial cells accumulate fat and protein, and are shed into the lumen (a cavity or passage) of the crop to give the milk. This holocrine secretion (a secretion consisting of disintegrated cells of the gland itself) has a cheese-like texture, and is composed of only 3% carbohydrate, 58.6% protein, 33.8% fat, and 4.6% ash. As in mammalian milks, the fat in the crop is predominantly medium-chain triglycerides. The milk contains immunoglobulin (IgA), which is possibly derived from the blood stream and reaches the crop through the saliva. Crop milk also contains considerable amounts of lecithin, phosphorous, and potassium. The adult’s saliva also contains amylase, mucous, and other material.

Crop milk is fed to the youngster for about two weeks following hatching. Milk-laden cells are initially sloughed off only when the crop is empty, assuring the milk is not diluted and altered by adult foods (essentially the youngster is not yet prepared to digest carbohydrates). As the chick matures, crop milk is fed in combination with other foods and milk-laden epithelial cells are shed only during the times of day when parents are provisioning their young. Then the supply of shed- able cells is exhausted. 

Crop milk assures a steady supply of and balance of nutrients to the rapidly growing altricial chicks (hatchlings are naked and blind and dependent on parents for food). The nutritional advantage of crop milk is suggested as a major factor in the success of pigeons and doves over other altricial species by by-passing the need to find high protein foodstuffs of animal origin.


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## Geranyl (May 13, 2004)

Just to add to that bit about IgA. Granted, it originates from the blood, but immunoglobulin A has the ability to be secreted through the the stomach and digestive tract lining. It is the immunoglobulin found in secretions, such as milk, mucosa, etc.


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## bigbird (Aug 19, 2000)

Thanks for the info.
Nice to know this.
Regards,
Carl


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## Grizz (Jul 24, 2004)

*Need Info?*

I have a grizzle hen who was mated by a young cock(unplanned),she is setting on her eggs only by herself with no help from the young cock,I imagine from his inmuturity,will she be able to hatch,feed and raise the young
on her own? Thanks.


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## Skyeking (Jan 17, 2003)

It has been my experience that a hen cannot raise two babies if there is no mate. She will either try to feed them and give up, or abandon them. I have two pets, Skye and Sonic, I had to hand raise as the mother abandoned them.

She will be able to raise one by herself, physically, but emotionally she might give up.

On the other hand, I have heard of others with hens that raised two babies by themself.

If the male is immature, maybe the eggs aren't even fertile. I would not take chances on her brooding the eggs, if they are fertile. If you let her brood them make sure you have a stand by couple to raise them just in case.

Treesa


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## Feefo (Feb 8, 2002)

<Milk-laden cells are initially sloughed off only when the crop is empty, assuring the milk is not diluted and altered by adult foods (essentially the youngster is not yet prepared to digest carbohydrates). >


That is interesting. I just placed a two day old woodpigeon with a pair of my nesting ferals. I did it just as Dad was relieving Mum on the nest. Instead of going to eat, Mum hung around and 5 minutes later I found her back on the nest and a bit later feeding baby. I checked baby's crop and it was full but soft, so I assume he got crop milk not seed.

I wonder whether the decision to let Mum do the feeding was based on the fact that she was the one with the empty crop?

Pigeons never cease to amaze me!

Cynthia


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## Christina Coughlin (Dec 29, 2002)

I had one hen that pushed her only chick out the door first thing in the morning after her mate bailed on her. I found the poor little girl out side the loft area in the pen, gave her a nice warm meal then let another pair take a shot at raising her. They did great! The odd thing though is that the original mom noticed where I put her baby so she joined in the feeding and helped feed all three chicks. I would try letting another pair (if there are other nesting pairs with chicks of the same age) raise them. Only one extra chick per pair though if you can, if that is not possible then it might be best to hand feed.


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