Background

In extensive farming systems, a reliable knowledge on demographic parameters (such as reproduction or mortality rates) is important for quantifying or simulating dynamics and productions of livestock populations. When unknown, the demographic parameters need to be estimated from data collected in the field. In developing countries, collecting data is the most difficult part of the work due to the dispersion and mobility of the herds and the fact that farmers do not keep written records about their herds. Three main survey approaches are used in practice (Landais and Sissokho, 1986; ILCA, 1990; Lhoste et al., 1993; Lesnoff et al., 2007): individual animal follow-up, herd follow-up (without animal identification) and cross-sectional retrospective surveys.

The retrospective approach is based on farmers’ interviews and their short- or long-term recall of the herds’ demography. This approach has long been used (the earliest document we found describing such approach goes back to 1975 although it was used prior to that, CIRAD-IEMVT, 1989). Different survey methods were designed for implementing quick diagnostics (e.g. Dumas, 1980; Peacock, 1983; CIRAD-IEMVT, 1988; Planchenault, 1992; Meyer et al., 1997; Bebe et al., 2003). Nevertheless, the methods have been the subject of little standardization or documentation. This limits the proper usage of the approach and generates variability in protocols implemented in the field, which in turn makes for difficulties in comparing and interpreting results.

In that context, a retrospective method – referred to as 12MO (meaning “the twelve-month method”) – was initially designed in collaboration with ILRI, ICRISAT, AGRHYMET and MRA Niger (Lesnoff et al., 2008) in a research project funded by DGCD-Belgium and located in Niger (PAD Project: “Improved livelihoods in the Sahel through the development and implementation of household level bio-economic decision support systems”). The method had the objective to enable the estimation of a large panel of annual demographic rates (e.g. reproduction, mortality, offtake and intake rates), while remaining simple enough to be easily implementable in the field and transferrable to local structures (NARS, technical services, NGOs, etc.).

The 12MO methodology was then revisited and improved in several research projects leaded by CIRAD in West Africa. The present handbook describes the new 12MO version (questionnaires, database and calculation routines).

General characteristics of 12MO and purposes

12MO focuses on ruminant livestock herds managed in small-holder farming systems. During the farmer’s interview, the enumerator’s role is to enumerate exhaustively the animals present in the herd at the date of survey, and then record all the demographic events (births, natural deaths, slaughtering, loans, purchases, etc.) that have occurred in the last twelve months.

As a consequence, the main purpose of 12MO is to evaluate short-term demographic impacts of human interventions (e.g. heath and feeding farming practices or genetic improvements) or of shocks (e.g. disease outbreak, drought or economic crises). The method was not designed to evaluate average herd productivities over long period of time. Nevertheless, the method can also provide smoothed estimates of abortion and parturition rates (see the regression method in Chapter 5).

12MO can only be used on herds of small or medium size. For practical feasibility reasons, the method does not apply to herds of several hundred animals. Furthermore, 12MO surveys are frequently restricted on the “reproductive herds”, i.e. the herds containing enough females to be able to renew by themselves. This can have consequences on the representativeness of the estimates (see Chapter 1).

Warning

Cross-sectional retrospective surveys, such as 12MO, have the advantages to be implementable in large areas and in all types of farming systems (even the nomadic ones) at the difference of herds’ follow-up surveys.

Nevertheless, due to biases arising from farmers’ recall (e.g. omission of animals or demographic events for taxes avoidance, cultural reasons or simple forgetfulness) and from approximations in the calculations of the demographic rates (Lesnoff, 2008; Lesnoff and Lancelot, 2009; Lesnoff, Submitted), it must be remembered that 12MO yields approximate results.

In addition, the reliability of the method is highly sensitive to the quality of the field work and the perspicacity of the enumerators. Intensive filed training and supervision are highly recommended to insure reliable data.

In any cases, the 12MO results must be considered cautiously. When possible, herds’ follow-up surveys (with or without animals’ identification) with regular fortnightly or monthly visits of enumerators should be preferred, particularly when the objective is to build a referential frame on demographic parameters.

Download

12MO materials

Contact

matthieu.lesnoff@cirad.fr