Farmers suffer their biggest sheep losses before weaning, with the majority of these occurring during the first 10 days and more than 20% during the first three days. Dr Josef van Wyngaard, technical manager at Voermol Feeds, talked to Glenneis Kriel about ways to limit these losses.
Effective lamb management is one of the biggest contributors to sheep production success, as high lamb mortalities not only result in fewer animals being available for slaughter but also affect the future sustainability of a farm by resulting in fewer replacement animals being available to keep the farm going.
Instead of letting nature take its course, management will be eased if ewes are grouped together and these groups are managed to lamb around the same time. Some farms run one lambing season, while others might have two or more.
When deciding on the time of lambing there are two big considerations. Firstly, the availability of labour and secondly the availability of food.
“The lambing season should fit into your production schedule, in other words fall outside holidays and the harvesting and planting season, and occur at a time when there is sufficient graze or pasture to help ewes regain condition after lambing,” says Josef Van Wyngaard, technical manager at Voermol Feeds.
Lambing Crates
The place of lambing is another huge influencer of lamb survival, which can be either in the veld under extensive conditions, in smaller camps or in lambing crates/pens. Dr Van Wyngaard points out that lamb mortalities averages around 5% in lambing crates in comparison with 10% in small camps and from 15% upwards under extensive conditions dependant on the external challenges such as predation etc.
This is because lambing crates ease production management and allow farmers to identify and address problems early, such as birth complications, ewes that have udder or milk production problems or lambs that are weak or malformed.
But the lambing crates also have various other advantages: The small spaces help to enhance bonding between ewes and lambs, which in turn prevent lambs from wandering off and dying, and it offers shelter against predation, extreme weather and theft. The system also makes it easy to pair ewes with their lambs for proper recordkeeping and to identify low-productive animals that need to be culled.
The crates however need to be kept dry and clean to reap these benefits, as pathogens build up faster in lambing crates than in camps because of the higher concentration of animals per area. Farmers can address this by limiting the time in crates to 10 days, 5 days before and 5 days after lambing, according to Van Wyngaard.
Alternatively, the ewes can lamb in small camps near the lambing crates and be moved with their offspring to the lambing crates shortly after lambing. “The crates would have to be bigger if ewes are going to lamb in them, to prevent the ewes from injuring their lambs,” Van Wyngaard says.
Ewes and their lambs should be kept in the crates for at least two days, but ideally for 3 to 5 days, as it takes between 48 hours to 60 hours for lambs to bond with ewes.
While sunshine is the best disinfectant, the cubicles should be washed and then covered with hydrated lime before straw bedding is added for the next group. The area should be well ventilated to prevent respiratory problems, but still provide shelter from the wind and cold.
The umbilical cords of the lambs should also be treated with iodine as soon as possible after birth to prevent infection.
From the crates, ewes and their lambs should be moved to small groups before being introduced to larger herds to make the lambs use to larger groups and to prevent them from being separated from their mothers.
The biggest drawback of lambing crates is their cost, but this is more than justified thanks to the higher lamb survival rate.
To maximise the return on investment, Van Wyngaard advises farmers to divide the herd into two or three groups, each with their own lambing period, instead of requiring one huge facility that is used only once a year. The crates can be used as a ram test station between seasons. Some farmers also only use lambing crates for ewes that carry multiples.
Colostrum
Van Wyngaard divides the feeding of lambs into three phases, with the first being linked to colostrum.
To help them build immunity against pathogens, lambs should receive about 210 ml of colostrum per kilogram of weight, within the first 24 hours after birth. There is no way of telling if the lambs have received enough, but those that received too little will grow poorly, be weak and be more vulnerable to diseases, according to Van Wyngaard.
Weak lambs can be dosed with 100 ml colostrum, 3 to 4 times per day for the first two days of their lives, saved from ewes that have already lambed.
Colostrum can be frozen, but should be warmed to room temperature before it is given to lambs. It should not be warmed above 37 degrees Celsius as this will destroy the antibodies associated with its immunity building benefits.
Colostrum also has to be used within an hour after collection or after being warmed to prevent a deterioration in quality. It can last for up to 7 days when stored in a fridge and up to 6 months when frozen.
In the absence of colostrum, farmers can buy commercial mixes or mix their own by using 500 ml full cream dairy milk; 120 ml cream or 3 table spoons of fish or baking oil; one egg and one table spoon of lactose or sugar. These alternatives, unfortunately, will not offer the same protection against prevalent diseases as the real deal, because it does not contain any antibodies.
Milk Production
Lambs are highly dependent on the ewes milk up until weaning, so farmers have to ensure their ewes are in good condition from reproduction to lambing, with high bypass protein containing licks or rations being especially important during the last 6 weeks before lambing. This will ensure quality colostrum and quality milk production, hence ensuring maximum lamb survival.
“The rations will all depend on the type and quality of feed available on the farm and whether the ewes are carrying multiple lambs or single lambs. Various companies offer commercial pre-mixes to help ewes maintain and regain condition,” Van Wyngaard says.
He points out that milk production of ewes usually peak four weeks after lambing. Thereafter, milk production declines, while the feeding demand of the lamb will increase. Therefore, ewe lick intake can be reduced after peak milk production without affecting milk yield. The use of lamb creep feed becomes more viable.
Creep Feed
“Lambs younger than 30 days have a feed conversion ratio (FCR) of 1:1 meaning the intake of 1 kilogram feed will result in a weight gain of 1 kilogram, with the feed conversion declining as lambs mature. To alleviate the impact of reduced milk supplies on lamb growth, lambs can be supplied with creep feed to unlock the full genetic potential of the lamb,” Van Wyngaard says. See Table 1 for more FCR information.
Lamb creep feed is a high energy and quality protein dense ration formulated to promote early rumen development in lambs and to maximise lamb weight gain over a shorter period. The creep feed should be fed to lambs from 7 to 10 days after birth, initially to get them used to creep feed, but also to stimulate rumen development to allow maximum uptake by the time the lambs reach 3 weeks of age.
The earlier, full development of the rumen, results in these lambs being ready to be weaned at an earlier age than lambs that did not receive creep feed and reduces weaning stress.
“Lambs are usually weaned when they weight more than 20 kg, which is reached at roughly 3 months of age in extensive production systems and around 2 months in an intensive 8-month production cycle. When creep feed is provided target weights of 25 kg to 30 kg can be reaches at 56 to 70 days for wool-breeds and even quicker for meat-breeds,” Van Wyngaard says.
Lambs that receive creep feed may also be sent to the market up to 50 days earlier than lambs that are left on pasture or only receive ewe’s milk, which in turn allows farmers to stock 10 to 20% more ewes, by freeing up valuable food sources. They also perform better in feedlots, because they are already use to energy dense feeds.
In addition, it has been found to have a positive impact on ewe reproduction.
“Lamb ewes subjected to feed stress during the first couple of months of their lives have been found to have a lower ovulation cycle and to produce fewer lambs during their lives than those that never experienced feed stress. This is probably also why lambing percentages of ewes that received creep feed when they were lambs are higher on average than those that did not,” Van Wyngaard says.
Supplying an all-purpose lick is not going to help, because lambs have a higher nutrient requirement than mature animals. Creep feed, for this reason, should contain at least 16% protein and have as high an energy content as possible.
Grain is a great source of energy, highly digestible and also helps to stimulate rumen development through the formation of butyric and propionic acids. Roughage, in contrast, is a poor producer of these acids and in effect not a great rumen developer. Lambs also have limited rumen capacity to unlock the nutritional value of roughage, according to Van Wyngaard.
High quality lucerne is the roughage of choice and should be included at 10% to stimulate intake.
Voermol uses SS200 and Procon 33 in combination with maize meal or barley grain, lucerne and molasses meal. These creep feed mixtures also contain feed additives to promote weight gain and to prevent bladder stones, acidosis, bloat and coccidiosis. It also contains various essential macro and trace minerals as well as vitamin A to improve animal performance.
“It pays to use a high-quality lamb creep feed, as farmers will be losing money for every day a lamb is not growing optimally,” Van Wyngaard says.
Creep feed intake is dependent on the mixture, veld or pasture quality and lamb parameters such as age and weight. On average lamb creep feed intake can vary from 15 kg to 25 kg per lamb over a 2 to 3-month period. See Table 2 for more information.
The creep pen should contain small enough entrances to prevent ewes from entering. The opening ranges from 20 to 25 cm in width (or 18 cm with thin ewes) and 40 to 50 cm in height. Alternatively large irrigation pipes can be used with holes large enough for a lambs head to access creep feed in the pipe.
To further prevent coccidiosis, creep feeders should be designed in a way that prevent lambs from standing in the feed troughs. The feeders should also be long enough to prevent competition between lambs, with 5 cm feeding space per lamb being optimal and 2,5 cm/lamb being the absolute minimum.
Table1: Impact of age on the feed conversion ratio of lambs in terms of kilogram feed taken in per kilogram increase in weight gain. (Vosloo, 1982)
| Age in days | Mass in kilogram | Feed conversion ratio (kg/kg) |
| 0 – 42 | 4,5 – 1,5 | 1:1 |
| 42 – 60 | 15 – 20 | 3:1 |
| 60 – 80 | 20 – 25 | 3.5:1 |
| 80 – 100 | 25 – 30 | 4:1 |
| 100 – 120 | 30 – 35 | 4.5:1 |
| 120 – 140 | 35 – 40 | 5:1 |
| 140 – 160 | 40 – 45 | 5.5:1 |
Table 2: Average creep intake and lamb weight at different ages. (De Villiers et al, 2002)
| Age in days | Creep intake
(g/lamb/day) |
Lamb weight
(kg) |
Creep intake/kg body weight (g) |
| 28 | 37 | 9.3 | 3.98 |
| 35 | 88 | 12.2 | 7.21 |
| 42 | 173 | 13.5 | 12.81 |
| 49 | 224 | 15.6 | 14.36 |
| 56 | 281 | 16.9 | 16.63 |
| 63 | 403 | 18.7 | 21.55 |
| 70 | 596 | 21.2 | 28.11 |
| 77 | 612 | 23.5 | 26.04 |
| 84. | 625 | 24.5 | 25.51 |
