Numerous studies have been completed in University College Dublin Lyons Research Farm initially by Professor Frank Crosby and in recent years under the guidance of Professor Tommy Boland.
All aspects from factors affecting colostrum quality and quantity to feeding management have been explored, with research ongoing.
This article summarises 10 top features of colostrum that every farmer should be mindful to.
1) Liquid gold
Ewes have excellent-quality colostrum - superior to cow colostrum - with the fat content typically ranging between 14% and 17%, while protein levels range from 18% to 20%.
Furthermore, half of the protein is present in the form of immunoglobulins or antibodies, making ewe colostrum the best possible feed for newborn lambs.
2) Three key benefits
Colostrum fulfils three main functions in the newborn lamb. A good feed of colostrum is essential to supplementing a lamb’s own heat and energy production (brown adipose tissue).
Colostrum provides the lamb with antibodies to the disease ewes have been exposed to. This is the only protection a lamb receives and it is reliant on this until its own immune system begins to function adequately.
Lastly, colostrum has a laxative effect that is crucial for clearing the digestive tract of all material accumulated while in the womb.
3) Timing is crucial
A lamb’s ability to absorb immunoglobulins remains high for the first six to eight hours.
About 20% to 25% of the immunoglobulins consumed will be absorbed into the blood stream and research at Lyons has shown that absorption will increase as immunoglobulin intake increases during the first 18 hours of life.
The volume of immunoglobulins decreases quickly, reducing by one third at 10 hours post-lambing and a further third by 18 hours post-lambing.
Therefore, feeding early is the best approach to give lambs the best possible start in life.ADVERTISEMENT
4) Sufficient volume
Along with timing, it is important that lambs receive a sufficient volume to allow optimum absorption of immunoglobulins and sufficient heat production.
A widely accepted figure is to aim to ensure lambs receive 50ml colostrum per kg bodyweight at least three times during the first 18 hours of life.
This equates to 250ml for an average lamb weighing 5kg in each feed. Colostrum requirements will be slightly lower for lambs born in a warm environment compared with lambs born outdoors.
5) Late pregnancy feeding
Colostrum accumulates in the mammary gland during the final few days of pregnancy, while antibodies get transferred from the ewes' blood to colostrum during this period. Underfed ewes will have poorer mammary development and hence lower colostrum yield.ADVERTISEMENT
Increasing the level of feed in underfed ewes will increase colostrum yield, but will never equal volumes produced where feeding is sufficient in the final six to seven weeks of pregnancy.
Where energy intake in the final four weeks of pregnancy is 20% deficient, it will reduce the volume of colostrum produced in the first hour and thereafter, while also reducing early lactation milk yield.
Protein and energy intake go hand in hand with a good response to increasing protein intake to 190g/ewe/day in Lyons where energy was adequate.
However, even where crude protein intake was trebled, there was no response where energy intake was severely restricted (0.4 of requirement).
The recommendation for a 70kg to 75kg twin-bearing ewe is to increase energy intake by 1MJ per day for each week in late pregnancy starting at 10MJ per ewe per day eight weeks from lambing and rising to 18MJ.
6) Ewe breed
Recent research carried out by Frank Campion and Tommy Boland shows that the breed, age and gestation length of ewes will influence the quantity and quality of colostrum produced.
There is a consensus that where late pregnancy nutrition is adequate, all breeds should be capable of meeting the requirements of newborn lambs.
7) Ewe colostrum is best
A trial assessing the performance on lambs fed ewe colostrum or a colostrum substitute showed a significant difference in performance.
Lambs that received ewe colostrum left their artificially-reared counterparts behind post-weaning and reached slaughter at an average age of 109 days versus 133 days for lambs receiving the colostrum alternative. There was no significant difference in carcase traits.
8) Ewe condition
As long as ewes are in reasonable body condition score (2.5 to 3.5) in a situation where the ewes are adequately fed, colostrum production will not be affected.
Thin ewes will obviously be under more pressure to produce colostrum, but there can also be issues with colostrum supply in over-fat ewes. This is due to slower progesterone clearance which inhibits milk let down.
9) Addressing let-down issues
You will frequently hear advice to administer oxytocin to stimulate milk let down in ewes facing challenges. It is important to note that this will only work if the colostrum is present.
10) Mineral interference
Work in Lyons Research Farm in the late 2000s highlighted the risk of excessive iodine consumption.
A ewe in late pregnancy requires in the region of 1ml iodine per day with toxicity levels 50 times higher.
Ewes will consume significantly more iodine than required if given the opportunity with excessive consumption in late pregnancy interfering with immunoglobulin absorption in lambs.
It is therefore important to ensure mineral supplementation is balanced, while if there is a fear of excessive intake withdrawing this excess for the final two weeks of pregnancy should help to alleviate problems.