Reproduction, Lambing and the Predation Window

#Two numbers that only mean something together

In a Karoo enterprise study, predation accounted for roughly three-quarters of recorded sheep losses. In the same study, total losses ran at 12 lambs killed or lost per 100 ewes in the flock (Conradie & Landman 2015).

Quote the first alone and you get the industry slogan: three-quarters of everything, an emergency, a war. Quote the second alone and you get the complacent version: 12%, the cost of doing business.

Together they give the real instruction. Predation is not most of your flock — it is most of your losses, which is a different and far more useful claim. What stands between you and a better weaning percentage is rarely nutrition, genetics or disease. It is a handful of decisions made in about six weeks of the year, and those six weeks are lambing.

#Set the mating plan, then work backwards

The rules are ordinary, well established and almost never all done at once.

Flush the ewes on a rising plane of nutrition for about three weeks before mating, targeting a body condition score of 3 to 3.5 at mating. Rising is the operative word — a ewe held at a good score does not respond the way a ewe gaining condition does (MSD Animal Health SA).

Run a mating season of three to six weeks, not "the rams live with the ewes". Gestation is about 150 days, in the range 147 to 152 (Overberg Agri), so a six-week mating gives a six-week lambing — a six-week window in which everything expensive happens. A year-round ram gives a year-round window, and no supervision plan survives that. Merinos have an extended breeding season, October to December mating being routine: a liberty and a temptation.

Ram ratios of roughly 1:40 for young ewes and 1:50 for mature ewes, with teasers at about 2% of ewe numbers to tighten the cycle (MSD). Check the rams — scrotal circumference, feet, teeth, condition — eight to ten weeks before mating, so a failed ram is replaceable rather than an empty season.

#The Highveld version, with its own contradiction in it

South African specifics

Meyerton, 75 ewes, lambing into the flush. The Highveld's best pasture quality is the spring flush, roughly September to November. Lamb into it and lambs go out onto rising feed with ewes that can milk. So: lamb from mid-September, mate from about mid-April, flush from late March.

Now look at what that does to the ewe. Her last six weeks of gestation run through August into early September — the tail of the winter protein collapse, when frost-cured standing grass is bulk without protein and intake falls even though the camp looks full. That is when the starvation-mismothering-exposure complex gets built.

The answer is not to move lambing. It is to accept that a Highveld spring lambing is a fodder-flow commitment: the protein and non-protein-nitrogen lick programme from roughly April/May to September/October is a structural cost of the lambing date, not an optional extra. Module 6 built the fodder flow; this is where you pay for it.

Then check it against Lesson 2's calendar. A September lambing puts newborn lambs and freshly lambed ewes into the rising wireworm season. The lambing date, the lick budget and the FAMACHA calendar are one decision made three times.

The flush does one more thing: the move onto lush green feed is the classic trigger for pulpy kidney, and a well-run spring rotation is a machine for making that transition happen. Clostridial cover is arranged before the feed changes, not after the first dead lamb — and the product, timing and schedule come from your veterinarian and the label.

#The four levers on lamb survival

The dominant cause of perinatal lamb mortality is not a disease with a name. It is the starvation-mismothering-exposure complex, plus birth stress, and it accounts for the large majority of losses (Haughey, JSAVA). The interventions are therefore managerial, not pharmaceutical.

Ewe nutrition in the last six weeks of gestation. This is the starvation end of the complex, and it is settled before the lamb is born, not after.
Shelter from cold, wet and wind at lambing. This is the exposure end. A wet newborn in a Highveld August wind is the case the whole complex is named for. Lamb into camps that have natural shelter, or build some.
Undisturbed bonding in the first six hours. This is the mismothering end. It sits in direct tension with the next section's demand for supervision — the resolution is quiet, distant, frequent observation, not frequent handling.
Separate the twin-bearing ewes. Two lambs is more feed demand and more mismothering risk in the same ewe, and she is the one who needs the shelter and the space.

#The predation window is the same window

This is where South African sheep farming leaves the textbooks: everything you just did to reduce mismothering also sets your predation loss.

The national loss estimate is approximately R1.39 billion a year, split Northern Cape R540.8 million, Eastern Cape R412.8 million, Free State R247.1 million, Western Cape R105.0 million and Mpumalanga R84.7 million (Van Niekerk 2010). Carry all three caveats with it, every time: it is self-reported in a telephone survey of 1 424 farmers, in a policy debate where a high number suits the respondent; it is an extrapolation from five provinces to a country; and it is in 2010 rands and has never been repeated. It is the best number available and a weak one.

The attribution is narrower than it is usually quoted. In the Northern Cape sample, losses were attributed to black-backed jackal 65%, caracal 30%, stock theft 3% and vagrant dogs 1%, with mean losses of 6.14% of total small livestock and 13% of lambs aged 0 to 6 months. That is a Northern Cape profile — not the Highveld's, and emphatically not a peri-urban smallholding's, where free-roaming domestic and feral dogs are plausibly the dominant predator. Shooting one of those raises Animals Protection Act 71 of 1962 and civil liability questions that shooting a jackal does not: that dog is somebody's property.

What it costs, what it earns

Guardian dogs, costed honestly. Across 94 South African farms from 2005 to 2011, perceived livestock depredation ceased in 91% of placements, with a gross mean annual saving of US$3 189 per farm (Rust, Whitehouse-Tedd & MacMillan 2013). The same paper carries the costs, and a course that quotes only the saving is selling: behavioural problems in 16% of dogs and premature mortality in 22%, mainly from snake bites. Budget for roughly one dog in five not completing its working life, with snake-aversion and behavioural training as line items.

The strongest South African non-lethal trial, published in 2015, ran on 11 Eastern Cape farms across one lethal-control year and two non-lethal years: mean stock loss fell from 13.6% to 4.4% and then 3.7%, total cost per head from US$23.41 to US$9.60 and then US$5.92 (McManus et al. 2015, Oryx 49(4)). Read the limits with it: no control group, 11 self-selected farms that knew they were being measured. Those are pre-2015 US dollars, so do not convert them and quote a rand figure. The durable number is the ratio — roughly four to one in favour of non-lethal by year two — and the durable instruction is to measure your own cost per head.

Contested — here is both sides

Does killing predators reduce your losses?

Against reflex culling. The UCT Karoo Predator Project reports that "killing caracals is probably counter-productive for farmers as it is associated with an increase in lambs lost the following year" — and states explicitly that "this is not true for jackals" (UCT). Carry that qualifier; most retellings drop it and turn a caracal result into a jackal one. On the jackal side, Minnie shows heterogeneous hunting pressure creating a source-sink system: unhunted reserves export jackals onto hunted farms, and farm subpopulations show a younger age structure and increased reproductive output (Minnie, Gaylard & Kerley 2016).

For targeted lethal control. The Predation Management Forum holds that skilled removal of an identified problem animal remains necessary. And the UCT result is correlational — causality could run the other way, since farms with rising losses cull harder.

Both can be true, and the distinction is the lesson: indiscriminate control backfires; targeted removal of an identified individual is a different intervention. What neither side has is your farm's before-and-after record. Keep one.

The legal position

Predator control is regulated, and the national instrument is not the whole answer. It is the Norms and Standards for the Management of Damage-Causing Animals in South Africa, Government Notice 512 in Government Gazette 40236, commenced 30 August 2016, made under the National Environmental Management: Biodiversity Act 10 of 2004 — not the TOPS regulations, which is how it is usually mis-cited. Deterrents such as fencing, collars and herding require no permit; cage traps, poison collars, darting, call-and-shoot, foothold traps, hounds, poison-firing apparatus and denning are restricted and require authorisation from the issuing authority, preceded by a severity assessment and inspection report (summary of GN 512).

Do not take a national rule on traps or poison from anyone, including this course. No national prohibition on gin traps or leg-holding devices could be confirmed here, and South Africa's own Predation Management Forum publishes technical guidance on their use — which is inconsistent with a national ban. The operative law is provincial, and use that causes unnecessary suffering is prosecutable under the Animals Protection Act 71 of 1962 regardless of any permit. Any vertebrate poison is a registered remedy under the Fertilizers, Farm Feeds, Agricultural Remedies and Stock Remedies Act 36 of 1947, bound by its label. Route all of this to your provincial conservation authority.

#Count it properly or you will fix the wrong thing

Track lambs weaned per ewe mated — not per ewe lambed, which quietly deletes your empty ewes. Track kilograms of lamb weaned per hectare and per small stock unit: per-hectare is the regenerative denominator. And record predation and theft on a separate line from mortality. A dead lamb entered as "mortality" sends you to a feed consultant; the same lamb entered as "predation" sends you to a kraal and a guardian dog.

The benchmark is published: Karoo commercial averages run at 87 lambs tagged per 100 ewes and a sales rate of 58% (Conradie & Landman 2015). Those are district averages carrying every farm in the survey, including the ones measuring nothing.

From the veld

Run the 75-ewe Delta Farms flock through it. Mate 75 ewes. At the Karoo average of 87 tagged per 100, you tag 65 lambs. Apply the 12-per-100-ewes loss rate: 9 lambs lost, leaving 56 weaned — 75 lambs weaned per 100 ewes mated.

Split those 9 the way the study did: roughly 7 to predation, 2 to everything else. Now ask the question that changes behaviour. A hard year of genetic selection and better licks might move tagging from 87 to 90 — three lambs. Closing half your predation loss is worth three or four, from a kraal, a tight lambing window and a dog. Same size — but only one of them shows up in your book as a line you can see.

Treat that as an illustration, not a forecast. Two district averages have been chained here to show the shape of the arithmetic. Your own two numbers are the ones that matter, and you will not have them until you record them.

Add theft on its own row while you are there. It is a loss channel, not a mortality, and it is recovered through identification: your registered mark under the Animal Identification Act 6 of 2002 is what turns a stolen sheep into a case a prosecutor can run. Died, taken by a predator and stolen are three lines in the book, because they send you to three different fixes.

#What changes on Monday

Split the mortality column in your lambing book in two: one line for died, one line for taken. Then set next season's mating date by counting 150 days back from the day your veld will be at its best, put the rams in, and take them out six weeks later.

Everything else in this module — the breed, the parasite protocol, the clip, the margin — sits downstream of those two acts.

#Check yourself

3 questions — answers explained as you go

1You mate 75 ewes, tag 65 lambs and lose 9 before weaning. What is your headline reproduction KPI?
Why: Weaned per ewe mated is the honest denominator because it carries everything: the ewes that never conceived, the lambs that died, and the lambs that were taken. Per ewe lambed deletes your empty ewes; survival-of-tagged-lambs deletes the empties and the pre-tagging losses too. The others are diagnostics under the headline number, not replacements for it.
2Which set of levers attacks the starvation-mismothering-exposure complex?
Why: The SME complex plus birth stress is the dominant cause of perinatal loss, and every lever against it is managerial rather than pharmaceutical. Note the tension inside the list: lever 3 wants the ewe left alone for six hours, and the predation plan wants her watched. Quiet, distant, frequent observation is the resolution. The last option is a genuine set of levers — it just acts on a different loss channel.
3A neighbour tells you the science shows that shooting jackals increases your losses the following year. What is wrong with that?
Why: This is the most commonly garbled result in South African predation management. The UCT Karoo Predator Project reports the association between lethal control and higher subsequent losses for caracal, and says in the same breath that this is not true for jackals. The jackal argument is a separate one — Minnie's source-sink work — and it is about the futility of sustained culling, not about losses rising next year. Both point the same way: indiscriminate culling is a poor bet, targeted removal of an identified animal is a different intervention, and only your own record settles it for your farm.