When should I put the ram in for spring lambs?

Short answer

147 days back from the first lamb you want — ram in October 1 for lambs from about February 25

Sheep gestation runs 144 to 150 days (Penn State); count about 147 back from the first lamb you want, so a ram in on October 1 gives lambs from around February 25. Raise the energy in the ration for the last third of pregnancy, give the CDT booster 3–6 weeks before lambing, and move the ewes to an observation pen several weeks out. Build one or two 4×4 or 5×5-ft jugs for every 10 ewes. A newborn lamb needs about 10% of its body weight in colostrum in its first 18 hours, half by 8 hours.

The arithmetic

Ram-in date = the first lamb you want − 147 days. October 1 → about February 25; November 1 → about March 28.
Lambing lasts as long as the ram stays in. A 45-day season — about two heat cycles — is a 45-day lambing.
Feed up for the last third: about +20% for a ewe carrying twins, more for triplets (Virginia Tech puts the energy need at +16% for twins, +31% for triplets).
Jugs = 1–2 per 10 ewes (Penn State). Twenty ewes, two to four jugs.

Why does one source say 10% colostrum and another nearly 20%?

Same lamb, very different numbers — because they are feeding different lambs.

NC A&T: 10% of body weight within the first 18 hours, half of it by 8 hours — a 10-lb lamb gets 16 oz
Oregon State EC 1427: 3 oz per pound of body weight in the first 18 hours, in four feedings at 0, 6, 12 and 18 hours — 30 oz for a 10-lb lamb
Penn State: Milk the ewe within several hours of birth and freeze colostrum in 3–4 oz portions
Oklahoma State (goats): 10% of body weight in the first 24 hours

Oregon State is writing about lambs raised entirely on the bottle, which get nothing from a ewe and need the colostrum for energy as well as antibodies. NC A&T is a minimum for a lamb that is also nursing. Both stop at 18–24 hours because that is when the gut stops absorbing antibodies.

For a lamb on the ewe, make sure of 10% in the first day and half of it early. For a bottle lamb, follow Oregon State's four feedings.

What changes your number

Body condition. Aim for 3 to 3.5 on a 5-point scale at lambing (Penn State). Fours and fives need watching in the last third; under 3 needs feed.
Barn space. About 16 square feet per ewe in the barn, more for big ewes (Penn State).
Jugs. 4×4 or 5×5 ft with sides at least 3 ft high, ewe and lambs in for 24–48 hours, and don't move her in until she has finished lambing (Penn State).
When to step in. Stage one can run 12–24 hours; once she is pushing, no progress in an hour — 30 minutes is better — means help (NC A&T).
Grain for lambing ewes. Virginia Tech's rule of thumb is a pound of grain per lamb she is carrying in late gestation.
A warm place. Penn State's "lamb hotel" is a 55-gallon barrel with a heat lamp; Oregon State found lambs at 68°F gain faster than at 46°F.

A number we won't give you

A hypothermia warming schedule for lambs — water temperature and minutes in the bath. The extension sources we used give the temperatures that mean trouble but not a bath recipe for lambs, and a scalded lamb is worse than a cold one. Dry it, warm it, and call your vet for a lamb under 99°F.

Newborn lamb — numbers to have on the barn wall

Check	Number	Source
Normal temperature	102–103°F	NC A&T
Hypothermic — warm it	100–101°F	NC A&T
Severe — warm to 99°F before tube-feeding	below 99°F	NC A&T
Colostrum, first 18 hours	10% of body weight; half by 8 hours	NC A&T
Tube-feed if not nursed	by 4 hours	NC A&T
Navel	7% iodine within a few hours	Penn State
Jug time	24–48 hours	Penn State

Rectal temperature. Warm a cold lamb before you feed it — it can't digest colostrum cold.

Lambing kit

Item	Why
Thermometer	The first check on any lamb that isn't up and sucking
7% iodine	Navel dip within a few hours
Feeding tube and 60 cc syringe	Colostrum for a lamb that can't nurse
Frozen colostrum in 3–4 oz portions	Penn State's portion size — thaw only what you need
Colostrum replacer, milk replacer, Pritchard teats	Triplets, a ewe with no milk, a rejected lamb
Gloves, lube, lamb puller	A malpresentation
Electrolytes and an energy drench	Listed by NC A&T
Heat lamp and a barrel	Penn State's lamb hotel
Jugs, 4×4 or 5×5, 3-ft sides	1–2 per 10 ewes

From Penn State's and NC A&T's lambing lists.

Run your own numbers

Pick the date you want the first lamb and it dates every job back to ram-in.

SpeciesFirst lamb wanted onBreeding season (days)

147 days before
Ram in — breeding for the first lambsPenn State: 144–150 days
102 days before
Ram out after a 45-day seasonYour choice; a short season means a short lambing
49 days before
Raise the energy in the ration — last third of pregnancyPenn State
28 days before
CDT booster for the ewesNC A&T (3–6 weeks before)
21 days before
Move ewes to the observation pen; jugs built, 1–2 per 10 ewesPenn State (several weeks before)
7 days before
Kit checked, colostrum in the freezer, heat source readyPenn State
Day 0
First lambs due
45 days after
Last lambs from the breeding season due

Gestation is an average; individual animals run a few days either side. Vaccine timing is the extension guidance — your vet’s plan for your herd comes first.

What lambing season costs in feed

The last six weeks and the first weeks of lactation are the dear ones: about +20% for a ewe carrying twins and +50% in milk on the sheep hay page's planning figures, at the time of year hay is scarcest. Lamb in late February and that lands on the coldest weeks of winter; lamb in April and it lands on spring grass.

Then stop planning from averages

The planner gives you the calendar. In Homestead Paradise you log each breeding and the app works out the due date and counts down to it, records how many lambs each ewe had, the birth weights and the adjusted weaning weights, and puts the flock's feed and vet costs on the books. 14-day free trial, no card.

Start your 14-day trial — no card

Keep planning

How much hay do goats need for winter?How much hay do sheep need for winter?How much hay does a cow need for winter?How many bales of hay do I need for winter?What does it cost to feed livestock through winter, per head?How much water do livestock drink in winter?

Sources

Every figure on this page comes from a land-grant university extension service, a government agriculture or energy agency, or a breed registry — never from another blog.