Depending on your lambing time and system, you may already be selling lambs fat, or maybe considering options for the next few months to ensure you hit the markets when they suit your lamb type. Feeding lambs can be a challenge and may depend on the year but whatever you decide, any feeding must be efficient.
Lamb performance, certainly up to weaning, is determined by the first few hours after birth. Ensuring good colostrum intake is key and is proven to affect health and growth through to weaning. If a lamb does not suckle quickly, at least within the first 6 hours of birth, then they should be fed replacement colostrum (either from ewe or purchased) at a rate of 50ml/kg liveweight. In the first six weeks of a lamb’s life milk is their source of nutrition.
Whether this be direct from the ewe, or from replacer in the case of pet lambs, this needs to be of adequate quality and quantity. If milk supply is inadequate, then lamb growth will be restricted. Feeding the ewe in the early weeks after lambing may be useful and required if grazing or forage is limiting but as time passes this becomes inefficient and it may be better to creep feed the lambs.
After 6 weeks of age lambs can rely on pasture, with or without lamb creep. At 6 weeks the lamb will have an energy requirement of 10MJ. They will receive approximately 6.5MJ energy from milk at this stage and 3.5MJ needs to be provided from the pasture, or creep feed if pasture is limiting.
The average weaning age is 90 days with a target weight of 30kg for lambs out of lowland ewes. This would be the optimum for a grass-based system. Weighing lambs at 8 weeks is useful to predict performance to weaning. If lambs have not achieved 85% (17kg of a 20kg target) they will continue to struggle up to and beyond weaning. Positive results can be seen by weaning these lambs early and feeding them high-quality creep feed.
By 12 weeks of age the energy requirement from pasture has increased to 100%. Lambs should be weaned once the lambs and ewes are competing for the available grass. Lambs should be given the priority grazing. Once the ewes have been body condition scored around weaning, and the grass requirements have been calculated, decisions can be made as to whether ewes need better grazing. It is important to understand the grass that is available and what is required. If grazing is tight creep feed for lambs may be more appropriate.
To make the best use of grazed grass it is important to manage it carefully to optimise quality and quantity. It is important to avoid lambs eating into the reserves for flushing and overwintering ewes. The leaf is the most nutritious part of the plant (>11.5 kg MJ Metabolisable Energy/kg Dry Matter).
Batching lambs according to their weight can enable feed to be targeted more efficiently. A good target for grass-based systems is to ensure >70% lambs are sold (finished or as stores) by tupping.
Keeping male lambs entire can help with higher growth rates due to better feed conversion. They should be separated from ewe lambs by 5 months of age and their finishing should be planned to avoid any store periods. The meat quality can be affected if they are not finished by 8 months of age.
Shearing store lambs means they eat more and finish quicker. The lambs need less lying area but their requirement for feeding space is NOT reduced. Shearing housed lambs reduces the risk of heat stress on high cereal diets. The lambs need to be housed for over a month to see the benefit and it is important to check there is no penalty at the abattoir for shorn lambs.
When selecting for slaughter it is important to handle and weigh the lambs regularly. Ideally, at least every 2 weeks as this ensures any health or nutritional problems are identified early and can be rectified without too much loss. Margins are always tight, so monitoring is important. Ensure any data is analysed and you know your market. Always check any carcase reports you receive.
Feeding replacement ewe lambs can be a challenge and it is important to get it right to ensure target bodyweight at weaning, mating, and lambing as well as target body condition score at lambing. Ideally, ewe lambs will only rear one lamb and lamb loss will be less than 15% from scanning to weaning. The aim is for long-term (lifetime) productivity.
It is important to target a liveweight gain of 200-250 grams per day from weaning to mating and continual growth of 130 grams per day from mating to 6 weeks pre-lambing. During lactation, ewe lambs should be fed 20% above mature ewe requirements. The biggest threats come from inadequate grass supply and feeding.
Silage for lambs needs to have a D-value of >65 or an ME value of >10MJ/kg DM. Silage with a shorter chop length will increase intakes and help with better growth rates, meaning less days to slaughter. A TMR mix gives a consistent diet but requires forage analysis to ensure it is correctly balanced. Concentrates are often financially rewarding for early-lambing flocks hitting the spring markets but should only be used to hit performance targets or if grazing is needed for other stock. If good quality grass is plentiful then do not feed concentrates. A feed conversion efficiency of 5:1 (kg gain: kg concentrate) is required to cover cost.
Feeding lambs can present a number of challenges and we are all aware how easy it is to end up with some deaths due to lambs gorging on feed. There are certain situations in which the risk of this will be higher and there are management protocols we can use to minimise the risk.
The transition and change of environment or feed sources are the biggest risk times for resulting lamb illness or death. Housing, change of field, change of grazing type, introduction of feed all can pose a risk.
1) Lambs are grazing in a field with a reasonable amount of grass. Feed is introduced to the lambs in a hopper. In an ideal situation the lambs will gradually introduce themselves to the feed in the hopper but that is a risk being taken. Ideally use a feeder that can be restricted such as an Advantage feeder or feed restricted quantities for the first few weeks gradually increasing to ad-lib. Ensure clean, fresh, readily available water is accessible.
2) Housing lambs from a grazing and hopper situation will mean that the lambs know what the feed in the hopper is rather than the forage they meet when housed. This increases the risk of the lambs gorging and getting ill. Whenever lambs are housed for the first time, they should be given hay, haylage or dry silage for the first 24 hours, ad-lib, to ensure they fill themselves up before the hopper is (re-)introduced. Ensure clean, fresh, readily available water is accessible.
3) Lambs being housed from just grazing, having not had access to hard feed, are likely to take a few more days to get onto a hopper fed concentrate and less likely to gorge BUT it is still possible. These lambs should be offered forage only for 24 hours to fill up before concentrate feed is offered. Ensure clean, fresh, readily available water is accessible.
4) Lambs grazing and moved to a field of different grass or forage crop. Adjustment should be accounted for. If the grazing is poorer quality to encourage concentrate feed, then ensure 24 hours in the new field before introducing the concentrate feed. If the grazing is much better quality, or has a lot of clover present, introduce for a few hours in the day and return to previous grazing for the rest of the day, gradually increasing the time on the new grazing area. If moving to forage crops from grass, ensure strip graze the forage crop and ensure a run back area onto grass is available.
If you require further information on Lamb Feeding & Avoiding Issues, then please speak to your local DN Sales Specialist or call Dugdale Nutrition on 01200 420200.