In tropical countries, feeds and feeding strategies are the main constraints of livestock production (Nsahlai et al., 1998; Savadogo et al., 2000; Abdou et al., 2011) particularly in Niger where rainy season is too short (three to four months) with often a decreasing rainfall, and the dry season is too long (eight to nine months) with acute forage shortages occurring from March to June. To avoid under feeding and ensure at least animal maintenance, farmers store crops residues and bush straws largely of low nutritive value, they have high fibre content which limit their degradability in the rumen and therefore their low intake; hence, animals fed with these feeds performed poorly (Ayantunde et al., 2007; Abdou et al., 2011). Thus, there is a need to develop more efficient ways of utilizing these available feed resources.
The overall goal of this study was to improve the milk production of Red Maradi goat breed and the growth performance of its kids by efficient use of feeds available in the study area. Specifics hypotheses were: (1) feeds differ according to their nutritive value;
(2) feeding lactating does with different levels of feeding, crushing and urea-treatment of stover influence post-natal performance of kids; (3) previous level of feeding and roughage processing influence the post-natal performance of dams and kids; (4) feeding levels of lactating does, crushing and urea-treatment of stover influence dam production and preweaning growth performance of kids; (5) pevious level of feeding and roughage processing do not affect dam and kids performances before weaning; (6) feeding levels of lactating does and roughage processing influence production and reproductive performance of does.
Chapter 3 dealt with the determination of nutrive value of feeds available in Maradi area of Niger. The three type of analyses showed that feed classes (cereal straws, legume crops residues and concentrates) differed in nutritive value; and within each class feeds also had differences. Cereals straws affected fibre fractions of cell wall (NDF, ADF, Hcel, Cel and
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lignin). Their NDF and ADF were higher than for legume crop residues. Treating roughages with urea did not affect cell wall content except cellulose but increased their N content. Urea-treating cowpea husk also reduced only cellulose but increased strongly its N content. The superiority of cell wall content in cereal straws than in legume crop residues and concentrates is similar to findings of others (Chenost and Kayouli, 1997;
Jayasuriya, 2002b; Abdou et al., 2011). The slight decrease in fibre fraction of cell wall with urea treatment is contrary to Wanapat et al. (2009) and may be due to a feeble urea dose (3%) used in the current study.
High variation of in sacco and in vitro degradation parameters between feed and within feed classes may be due to difference in physical characteristics and chemical composition which agree with earlier reports (Vitti et al., 1999; López et al., 2005;
Maghsoud et al., 2008).The increase rate of degradation (c) and effective degradability (ED) with cereal straws as a result of urea treatment may be due to increased nitrogen content and availability of OM which can stimulate bacteria synthesis in the rumen and cell wall digestion (García-Martínez et al., 2009; Abate and Melaku, 2009). The fact that urea treatment increased Trdeg, MY and (C) confirms an increase in quality and is associated increased rumen microbial activity, cell wall digestion (Chenost and Kayouli, 1997; Owen et al., 2012) and ME value. Based on the response of urea treatment of roughages, the nutritive value, and availability of feeds, millet stover, groundnut haulms, wheat bran and cottonseed cake were chosen to formulate diets for subsequent experiments. Effects urea treatment on roughages were well observed through in vivo and in vitro analyses whereas proximate analysis showed an increase of N content but no significant effect on fibre content. It is important to note that proximate analysis alone is not sufficient to determine nutritive value of feeds; in sacco and/or in vitro analysis should be combined.
Chapter 4 dealt with the effect of feeding levels of lactating does on post-natal performance of kids before 14 days. There was a linear increase of dry matter intake (DMI) and dams’ metabolisable energy intake (dMEi) with increasing level of feeding which may be explained by increasing levels of feeding. However, milk yield did not increase significantly despite the linear increase in dry matter and metabolisable energy
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intakes which may be explained by low DM and ME intakes and the energy mobilized from body tissue for milk production at the early stage of lactation. The variation of kid metabolisable energy intake among treatments may be due to birth type, variation in kid initial weight and probably to colostrum intake which had higher ME than normal milk.
Urea treatment of millet stover increased DMI intake compared to the untreated one. This may be explained by the fact that urea treatment on millet stover wetted and perhaps softens the feed and increased its digestibility thereby heightening its appeal and palatability which is in agreement with others (Wanapat et al., 2009; Gunun and Wanapat, 2012; Gunun et al., 2013) who reported increased DMI after treating cereal straws with urea. The no-effect of crushing millet stover (CMS) on DMI was contrary to our expectation and may be attributable to goats’ behaviour.
All group of lactating does during the first two weeks postpartum lost body weight in agreement with Greyling et al. (2004) using indigenous and Boer goats in South Africa and Djibrillou et al. (1998) with Red Maradi goat. This loss of body weight may be due to lower DM and ME intakes after kidding and therefore does mobilize own energy reserves to satisfy the extra energy requirement for milk production at this particular stage of lactation. Djibrillou et al. (1998) attributed body weight loss of lactating does to the unbalanced energy requirement and energy provided in the diet.
Chapter 5 dealt with the effect of level of feeding dams on the preweaning growth performance of kids where the levels of feeding increased DMI, ME and milk yield (myd). The increased dam metabolisable energy intake (dMEi) is due to increased DMI.
The increase of myd could be explained by increased dMEi which is in agreement with others (Montaldo et al., 1997; Min et al., 2005; Morand-Fehr et al., 2007; Luka and Kibon, 2014). However, the daily milk yield was still lower than expectation in the present study or observed in other studies with Red Maradi (Sokoto) goat (Djibrillou et al., 1998; Luka and Kibon, 2014) and Sahelian goat (Sangaré and Pandey, 2000). The low milk yield observed in the current study may due to low DMI and therefore low metabolisable energy intake.
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Kid metabolisable energy intake (KMEint) increased with level of feeding dams but the KMEint is lower than requirements of Sahlu et al. (2004) and NRC (2007). This may be due to the low consumption of milk and ME as milk yield was relatively low, which could explain the low growth rate of kids before weaning. Kid weaning weights in the present study are quite similar to those reported by Makun et al. (2008) and lower than those reported by others (Djibrillou, 1989; Sangaré and Pandey, 2000; Marichatou et al., 2002).
Differences in weaning weights of kid might be attributed to kids’ ME intake and partially to experimental conditions, perhaps to genotype and genetic dilution of red Maradi goats at Caprine Centre.
In Chapter 6, the effect of feeding levels on production and reproductive performance of dams were studied between interval of two kiddings, where DMI, myd and dam final weight (dfwt) increased with levels of feeding in agreement with others (Chobtang et al., 2009; Luka and Kibon, 2014). The relatively low milk yield in the present study could be attributed to lower feed intake and therefore lower ME intake compared to recommended value (AFRC, 1998), and perhaps to genotype and genetic dilution of red Maradi goats at Caprine Centre of Maradi. The relative increase in conception rate with increased feeding level is in agreement with others (Hart, 2008; McKenzie-Jakes, 2008) and may be explained by an increase of nutrients intake with graded levels of feeding.