Casting the net wider in quest for optimum ewe productivity

A new EU knowledge exchange programme is aiming to increase output in key sheep producing regions including Ireland, write

THE EU is only 85pc self-sufficient in sheep meat, but technology could help to change that: SheepNet is an EU-funded project aiming to improve ewe productivity.

Ewe productivity (number of lambs reared per ewe joined) is a combination of prolificacy, reproduction success, embryonic and lamb survival.

SheepNet is designed to stimulate knowledge exchange between research and stakeholders to widely disseminate best practices and innovations, with the objective of increasing ewe productivity.

SheepNet involves the six main EU sheep producing countries (Ireland, France, UK, Romania, Spain and Italy) and Turkey.

FARMING SYSTEMS

There is a wide diversity of sheep farming systems in the EU and Turkey, due to different ewe genotypes, environmental conditions, etc.

Data was collated on 19 of the main sheep systems from the seven countries involved to determine reproductive rates, pregnancy success and lamb mortality.

The systems were classified according to the environmental conditions (mountain areas, lowlands, etc), productive aptitudes (meat, dairy or dual-purpose) and how frequently the ewes lamb.

In most systems the ewes lambed once annually. However in accelerated reproductive systems ewes lambed either three times in two years or five times in three years.

FERTILITY AND PROLIFICACY

In systems where ewes lambed once annually, average fertility rates range from 83 to 95pc.

Consequently there is a significant number of non-productive ewes in the flocks (average 5-17pc), which can be as high as 50pc in the less efficient flocks, eg ewe-lambs (lambing as one-year-olds), particularly in meat systems.

Therefore in accelerated systems average fertility rates per lambing range from 59 to 77pc.

Oestrous synchronisation and artificial insemination are mainly implemented in dairy systems of France, Spain and Italy, yielding average fertility values around 50pc (ranging from 15 to 82pc).

Regarding prolificacy (litter size), average values ranged from 1.2 to 1.7 lambs born per ewe lambing.

Prolificacy tended to be higher in lowlands systems (1.47) compared to systems in mountain areas (1.31).

Despite the higher complexity of the management for accelerated reproductive strategies, the average prolificacy (1.48) did not differ much from that obtained in the systems in which ewes lambed once per annum (1.40).

PREGNANCY SUCCESS

In general there is a lack of data on the incidence of abortion on commercial farms. Data on abortion were only provided for seven of the farming systems.

The incidence of abortion ranged from 1 to 5pc, although in some farms it was assessed to be over 12pc.

Considering that scanning (ultrasound echography) seems to be implemented only in certain systems, there is concern about the consistency and reliability of some existing data.

LAMB MORTALITY

Stillbirth or perinatal mortality ranges from 2 to 13.5pc but is not usually recorded in many systems of sheep production. Therefore, information about mortality is probably underestimated for many systems.

Most systems determine lamb mortality from birth to weaning, and average values range from 2 to 18pc. Lamb mortality tends to be higher during winter, as well as towards the end of the lambing season.

PRODUCTIVITY

The average number of lambs reared per ewe joined range from 1 to 1.5 in most of the systems assessed, even for accelerated reproductive systems.

Productivity yields are slightly higher for lowlands systems (1.26) than mountains (1.08) systems. An example of a prolific system is the Assaf breed in Spain, which is permanently indoors in an accelerated reproductive system rear up to 2.5 lambs per ewe joined.

The data presented in this paper clearly illustrates that there are significant opportunities to improve ewe productivity in most systems by improving reproduction success and lamb survivability thus improving farm profitability.

Dr Tim Keady and Dr Alan Bohan are based at the Animal & Grassland Research & Innovation Centre, Teagasc, Athenry, Co Galway