|Livestock Research for Rural Development 31 (2) 2019||Guide for preparation of papers||LRRD Newsletter||
Citation of this paper
In order to study the effect of the season on the evolution of ewes' body weight (W) and body condition score (BCS) during their breeding cycle, 22 Ouled Djellal ewes, reared in an extensive system, have been managed in an accelerated lambing rate (3 lambing in 2 years). The combined weighing and body score assessment of the ewes was carried out every month.
The results highlighted the influence of the mating season on the evolution of BCS and weight from ewes in a system where food resources are always linked to climatic conditions. The highest value of BCS was marked at the time of the mating season (2.59±0.38) but the highest live weight was noted at the time of lambing (54.7± 4.1 kg).
Keywords: Algeria, BCS, mating season, Ouled Djellal, reproduction
Dans le but d’étudier l’effet de la saison sur l’évolution du poids vif (PV) et de la note de l’état corporel (NEC) des brebis au cours de leur cycle de reproduction, 22 brebis de race Ouled Djellal, élevées dans un système extensif, ont été soumises à un rythme d’agnelage accéléré (3 agnelages en 2 ans). La pesée et la notation corporelle des brebis, ont été réalisées chaque mois pendant 2 cycles de reproduction, d’avril 2017 à juillet 2018 (16 mois).
La saison de lutte influence l’évolution de la NEC et du PV de brebis en système extensif où les ressources alimentaires sont toujours liées aux conditions climatiques. Les plus fortes NEC ont été au moment des luttes (2,59±0,38) mais les poids vifs les plus élevés ont été au moment des agnelages (54,7± 4,1 kg).
Mots clés: Algérie, lutte, NEC, Ouled Djellal, reproduction, système d’élevage accéléré
Sheep farming is an important agricultural activity in Algeria. It contributes 52% of livestock production and 35% of total agricultural production (Benaissa 2001). Meat, wool, milk and skins are the products offered by this species. These products are intended to supply the national market, or for family self-consumption (Khelifi 1999). It thus represents a source of income for many families in more than half of the country (Mohammedi 2006).
Despite the importance of the sheep population in Algeria, however, livestock holdings are still marked by the extensive nature of production systems, which are highly dependent on climatic hazards, and the low productivity. As well as the lack of an appropriate breeding policy, breeders are left to their own devices, leading their herds according to their ancestral knowledge (Dekhili 2010; Deghnouche 2011), while there are many techniques that can improve the level of production (Abbas et al 2002).
This study was carried out to study the effect of the season on the evolution of the ewes' body weight (BW) and body condition score (BCS) during their breeding cycle.
The study involved 22 Ouled Djellal ewes reared in an accelerated rearing system (3 lambing in 2 years). The diet was based on steppe meadows and cereal stubble. A feed supplement (crushed barley and wheat bran) of 400 - 500 g/ head/day was given for 1 month, before and after the mating period (flushing) and one month before the planned lambing (steaming up).
The combined weighing and body assessment of the ewes was carried out every month. Body scoring was performed using the technique of Russel et al (1969) with a score of 0 to 5. The determination of the means, standard deviation and coefficient of variation was carried out using the IBM SPSS software (version 24, 2015 for MAC).
The study of variations in body condition score BCS and live weight over two successive reproduction cycles (Figure 1) distinguished three phases: an increasing phase started 2 months before the mating season (May and January) and continued until the 4th month of gestation (September and May). This represented an increase of 0.27 and 0.17 points and 6.17 and 4.44 kg for summer and winter mating seasons, respectively. This increase was due on the one hand to the development of fetuses during gestation, and on the other hand to the administration of flushing before and after mating.
|Figure 1. Evolution of ewe weight (W) and body condition score (BCS) for two successive mating periods|
A regression period occurred between the first lambing (October) and 30 days later. It was characterized by weight loss (0.15 and 3.94 kg for summer and winter mating, respectively) and lipid reserves (0.32 points at 2nd lambing). After gestation, the ewes continued to draw from their body reserves, especially during their first month of lactation when lambs feed only on their mothers' milk.
A new phase of progression began in November until the end of lactation and represented the period of reconstitution of body reserves, when the lambs begin to consume other foods, such as forages and concentrate (Chemmam et al 2014).
There was a significant influence of the mating season on the evolution of the BCS and the favorable ewe's milk yield for the winter season. For the BCS the highest value was marked at the time of mating (2.59±0.38) but the highest weight was noted at the time of lambing (54.7± 4.1 kg) (Table 1).
|Table 1. Evolution of Body Condition
Score (BCS) and live weight (W) according
to mating and lambing seasons (n=22)
During their gestation and first month of lactation, the ewes replenished their reserves on spring pasture and cereal stubble in summer. This makes it possible to achieve a better body condition at lambing.
However, during the summer control season the ewes were unable to meet their gestation and lactation needs. In addition, the health aspect (parasitism) also contributed to this degradation.
The results of our study highlight the influence of the mating season (summer or winter) on the evolution of body condition and live weight in an intensive system in Algeria where food resources are always linked to climatic conditions.
This article was presented at the 24th Meetings on Ruminant Research,5-6 December 2018, in Paris.
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Received 18 December 2018; Accepted 12 January 2019; Published 1 February 2019
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