Effects of restricted feeding and re-feeding of Barbarine lambs: intake, growth and non-carcass components

Abstract

Link to this article: http://journals.cambridge.org/abstract_S1357729805000846How to cite this article: M. Mahouachi and N. Atti (2005). Effects of restricted feeding and re-feeding of Barbarine lambs: intake, growth and noncarcass components. AbstractFifty intact male Barbarine lambs were used to assess the effects of restricted feeding and re-alimentation on intake, growth and non-carcass components. Five lambs were slaughtered at the start of the trial, the remainder were randomly allocated into three groups. One group was offered only stubble grazing (low : L), another, also on stubble, received, indoors, an average of 80 g dry matter (DM) of soya-bean meal per day (medium : M); the third group was kept indoors and had free access to hay and 450 g of concentrate per day (high : H). At the end of this restriction period (70 days), five lambs per group were slaughtered. The 10 remaining animals in each group were divided into two groups receiving concentrate and hay ad libitum. The crude protein content (CP) of the concentrate was 160 and 210 g/kg DM for the two treatments, respectively. At the end of the trial all animals were slaughtered at 37·61 ± 2·05 kg live weight. In the restriction period, sheep from the H group had a significantly higher growth rate (108 g/day) than L group (61 g/ day) with M intermediate. The empty body weight (EBW) as well as carcass weight were significantly higher in H than in restricted sheep. Digestive tract components and liver weight were the same for all treatments. However, skin weight was significantly ( P < 0·01) affected by dietary treatment. The heart and lungs were also heavier in H lambs than in the two other groups. Conversely, the relative weights of gut and liver as proportion of EBW increased in restricted lambs, while that of skin and red organs was not affected by diet. In the re-alimentation period and with both CP levels, the compensating animals showed the same growth rate as the previous unrestricted ones. At the end of this period, organ weights, in both absolute and relative value, were comparable among lambs of the three nutritional histories and two CP level. The absolute and proportional daily gains were similar in all animals for visceral and external organs, but they were significantly higher in H lambs than in L and M ones for the omental and mesenteric fat and testis.

Effect of different feed restriction regimens on lamb performance and carcass traits

“…This higher gain could not be attributed to DMI because intake values were not different between realimented (RR) and control groups, but possibly due to the better FG in realimented lambs and/or the decreased heat production during the restriction and its continuation during realimentation (Yambayamba et al, 1996). These results are in agreement with those of Mahouachi and Atti (2005), but not with those of Homem Junior et al (2007), who reported that rapid gain during realimentation was associated with increased feed intake. The apparent inconsistency may be explained by the differences in levels of restriction and realimentation, composition of diets, age of animal, and periods of restriction and realimentation (Tolla et al, 2003).…”

“…Also, it has been shown that moderate feed restriction resulted in appreciable changes in the metabolism of the liver tissue (Tovar-Luna et al, 2007). In other reports, liver weight was not affected by a period of feed restriction followed by realimentation (Mahouachi and Atti, 2005;Shadnoush et al, 2011;Abouheif et al, 2013). The high growth rate for liver tissue exhibited by compensatory-grown lambs probably reflects hypertrophy of the liver tissue upon realimentation after a period of growth restriction (Sami et al, 2013).…”

“…The effect of DMI restriction on lamb performance has been studied (Mahouachi and Atti, 2005;Kamalzadeh et al, 2009). Regarding lambs fed ad libitum, lambs held to less than maximal DMI had reduced ADG as a function of the plane of nutrition, thereby resulting in inadequate intake of nutrients required to sustain normal growth and development (Dashtizadeh et al, 2008;Abouheif et al, 2013).…”

“…Abouheif et al (2013) found that compensatory growth was better expressed when feed restriction occurred at 36 than 30 kg body weight in indigenous Najdi sheep from Saudi Arabia. There are conflicting results about the amount of feed intake after a period of feed restriction; some authors reported a significant increase in feed intake (Homem Junior et al, 2007;Dashtizadeh et al, 2008), whilst others reported no significant difference (Mahouachi and Atti, 2005;Shadnoush et al, 2011).…”

“…Compensatory growth is manifested in the feedingestion ability of previously restricted animals to outgain their better counterparts when given free access to good quality feed. Compensatory growth may be associated with lower maintenance energy requirements brought about by reducing liver and gut masses and protein turnover (Mahouachi and Atti, 2005;Shadnoush et al, 2011), an increase in the growth efficiency, and changes in body composition (Kamalzadeh et al, 2009). The response varies according to the breed, duration and severity of restriction, duration of realimentation, quality of the diet and stage of development at the start of restriction (Al-Selbood, 2009).…”