Publications

In this work, natural fibres (sisal, kenaf, hemp, jute and coir) reinforced polypropylene composites were processed by compression moulding using a film stacking method. The mechanical properties of the different natural fibre composites were tested and compared. A further comparison was made with the corresponding properties of glass mat reinforced polypropylene composites from the open literature. Kenaf, hemp and sisal composites showed comparable tensile strength and modulus results but in impact properties hemp appears to out-perform kenaf. The tensile modulus, impact strength and the ultimate tensile stress of kenaf reinforced polypropylene composites were found to increase with increasing fibre weight fraction. Coir fibre composites displayed the lowest mechanical properties, but their impact strength was higher than that of jute and kenaf composites. In most cases the specific properties of the natural fibre composites were found to compare favourably with those of glass.

Traditional rearing system based on pasture and hay supplementation was compared with rearing systems based on supplementation of barley based concentrate on Tuj lambs. Male Tuj lambs (n=18) were used in three groups with six lambs in each group. Group T was a control managed as a traditional system with grazing and hay as the main feed sources. In Group TC, lambs were separated from the main flock once a day and offered 500g concentrate per animal. Lambs in Group C were also separated from the main flock and fed 175g per day per animal hay and 1kg per day per animal concentrate. At the end of a 150 days experimental period, lambs were slaughtered and carcasses were evaluated. Liveweights of Groups T, TC and C were 36.4, 38.2 and 41.3kg, respectively, and cold carcass weights were 17.1, 18.1 and 19.7kg, respectively (P<0.05). The results suggest that liveweight and carcass weight can be improved by supplementary feeding of lambs. Economic aspects of concentrate usage were also evaluated. It was concluded that feeding animals with barley based concentrate instead of hay is profitable for breeders.

Traditional rearing system based on pasture and hay supplementation was compared with rearing systems based on supplementation of barley based concentrate on Tuj lambs. Male Tuj lambs (n=18) were used in three groups with six lambs in each group. Group T was a control managed as a traditional system with grazing and hay as the main feed sources. In Group TC, lambs were separated from the main flock once a day and offered 500g concentrate per animal. Lambs in Group C were also separated from the main flock and fed 175g per day per animal hay and 1kg per day per animal concentrate. At the end of a 150 days experimental period, lambs were slaughtered and carcasses were evaluated. Liveweights of Groups T, TC and C were 36.4, 38.2 and 41.3kg, respectively, and cold carcass weights were 17.1, 18.1 and 19.7kg, respectively (P<0.05). The results suggest that liveweight and carcass weight can be improved by supplementary feeding of lambs. Economic aspects of concentrate usage were also evaluated. It was concluded that feeding animals with barley based concentrate instead of hay is profitable for breeders.

The purpose of this study was to examine developmental and dietary regulation of the potential for peptide transport via PepT1 and morphological changes in the gastrointestinal tract of lambs. A 2×4 factorial arrangement of treatments with four blocks was created based upon gender, birth type (single or twin), birth weight, birth date, and breeding with 32 cross-bred lambs. Lambs were randomly allotted at birth to receive or not to receive a creep diet and all lambs were allowed to nurse. Sampling times of 2, 4, 6, or 8 weeks were randomly allotted to lambs. Samples for RNA extraction and histological evaluation were taken from the dorsal rumen, ventral rumen, omasum, duodenum, jejunum, and ileum. The DMI was similar for ewes nursing lambs that had or did not have access to creep feed (2,630 and 2, 574gh−1 per day, respectively). Lambs with access to creep feed consumed DM at the rate of 2, 22, 129, 219, and 227gh−1 per day, respectively when they were approximately 12, 13, 20, 38, and 52 days of age. Cumulative weight gain was similar for both groups of lambs and increased linearly (P<0.001) with age. Villi were about 7% shorter (P<0.09) in lambs receiving creep feed. Papillary height and width increased linearly (P<0.01) with age. In the stomach, total and keratinized epithelial cells decreased (P<0.03 and <0.01, respectively) with age and were fewer (P<0.01) in lambs receiving creep feed. Even with the modest intakes observed in this study, creep feeding appeared to slightly alter the mucosal structure of the small intestine and was advantageous in that it stimulated papillae growth, thus predisposing the rumen for the introduction of feed into the diet. A 2.8kb oPepT1 mRNA was present in all tissues studied by 2 weeks and age did not significantly influence the abundance of oPepT1 mRNA in the small intestine or stomach. Abundance of oPepT1 mRNA was greatest in the jejunum (P<0.01) of the small intestine and in the dorsal rumen (P<0.01) of the stomach. Lambs not receiving the creep diet had a greater (P<0.02) abundance of oPepT1 mRNA in the rumen, particularly the dorsal rumen. Because no dry feed and little or no milk entered the rumen when no creep was fed, it is possible that a stimulus for development from the non-luminal direction, possibly blood-borne, may be involved in the ontogenesis of oPepT1. That PepT1 mRNA was present indicates that peptide transport occurs in the young lamb and the rumen and omasum appear to be involved in this process.

The purpose of this study was to examine developmental and dietary regulation of the potential for peptide transport via PepT1 and morphological changes in the gastrointestinal tract of lambs. A 2×4 factorial arrangement of treatments with four blocks was created based upon gender, birth type (single or twin), birth weight, birth date, and breeding with 32 cross-bred lambs. Lambs were randomly allotted at birth to receive or not to receive a creep diet and all lambs were allowed to nurse. Sampling times of 2, 4, 6, or 8 weeks were randomly allotted to lambs. Samples for RNA extraction and histological evaluation were taken from the dorsal rumen, ventral rumen, omasum, duodenum, jejunum, and ileum. The DMI was similar for ewes nursing lambs that had or did not have access to creep feed (2,630 and 2, 574gh-1 per day, respectively). Lambs with access to creep feed consumed DM at the rate of 2, 22, 129, 219, and 227gh-1 per day, respectively when they were approximately 12, 13, 20, 38, and 52 days of age. Cumulative weight gain was similar for both groups of lambs and increased linearly (P<0.001) with age. Villi were about 7% shorter (P<0.09) in lambs receiving creep feed. Papillary height and width increased linearly (P<0.01) with age. In the stomach, total and keratinized epithelial cells decreased (P<0.03 and <0.01, respectively) with age and were fewer (P<0.01) in lambs receiving creep feed. Even with the modest intakes observed in this study, creep feeding appeared to slightly alter the mucosal structure of the small intestine and was advantageous in that it stimulated papillae growth, thus predisposing the rumen for the introduction of feed into the diet. A 2.8kb oPepT1 mRNA was present in all tissues studied by 2 weeks and age did not significantly influence the abundance of oPepT1 mRNA in the small intestine or stomach. Abundance of oPepT1 mRNA was greatest in the jejunum (P<0.01) of the small intestine and in the dorsal rumen (P<0.01) of the stomach. Lambs not receiving the creep diet had a greater (P<0.02) abundance of oPepT1 mRNA in the rumen, particularly the dorsal rumen. Because no dry feed and little or no milk entered the rumen when no creep was fed, it is possible that a stimulus for development from the non-luminal direction, possibly blood-borne, may be involved in the ontogenesis of oPepT1. That PepT1 mRNA was present indicates that peptide transport occurs in the young lamb and the rumen and omasum appear to be involved in this process.

Ovulation pattern (rate and time) of 35 adult (age: 2–3.5 years, average body weight: 25–36kg) normal cycling (nulliparous and parous) Jakhrana goats native to the semi-arid areas of India was investigated. Randomly selected goats (seven per group) were laparotomized 20, 28, 36, 48 and 54h following natural oestrus and were observed for the onset of ovulation, its sequence and rate. None of the goat ovulated 20h post-onset of natural oestrus. Ovulation occurred 28h post-onset of oestrus (towards the end of the oestrous period) in Jakhrana goats and reached to its peak at 36h of post-oestrus. No further increase in ovulation rate 48 to 54h post-oestrus was observed in this breed. Mean ovulation rate was 1.33±0.10 (range 1–2). Study concluded that Jakhrana goat ovulated towards the end of oestrus and ovulation was over 12h after the end of oestrous period. Ovulation rate in Jakhrana goats followed a similar trend to other large sized goat breeds of Indian origin.

Ovulation pattern (rate and time) of 35 adult (age: 2–3.5 years, average body weight: 25–36kg) normal cycling (nulliparous and parous) Jakhrana goats native to the semi-arid areas of India was investigated. Randomly selected goats (seven per group) were laparotomized 20, 28, 36, 48 and 54h following natural oestrus and were observed for the onset of ovulation, its sequence and rate. None of the goat ovulated 20h post-onset of natural oestrus. Ovulation occurred 28h post-onset of oestrus (towards the end of the oestrous period) in Jakhrana goats and reached to its peak at 36h of post-oestrus. No further increase in ovulation rate 48 to 54h post-oestrus was observed in this breed. Mean ovulation rate was 1.33±0.10 (range 1–2). Study concluded that Jakhrana goat ovulated towards the end of oestrus and ovulation was over 12h after the end of oestrous period. Ovulation rate in Jakhrana goats followed a similar trend to other large sized goat breeds of Indian origin.

Male kids (110) from six goat genotypes, i.e. Boer×Angora (BA), Boer×Feral (BF), Boer×Saanen (BS), Feral×Feral (FF), Saanen×Angora (SA) and Saanen×Feral (SF) and two slaughter weight groups, i.e. Capretto and Chevon (liveweight at slaughter 14–22 and 30–35kg, respectively) were compared for growth, carcass and meat quality characteristics. Due to their better growth rate, kids from BS and SF genotypes reached the required liveweight for slaughter earlier than kids from other genotypes used in the study. Chevon kids had a significantly (P<0.05) lower average daily gain (119g per day) compared to Capretto kids (171g per day). SA, SF and FF kids deposited more internal fat in comparison to kids from other genotypes. The dressing percentage of kids ranged from 51 to 54%, with significant differences between genotypes. BS and SF kids had longer carcasses, while BF kids had larger eye muscle area compared to other genotypes. Goat carcasses had a thin subcutaneous fat cover (1.6–2.2mm). Genotype had a significant (P<0.05) influence on cooking loss, pigment concentration and muscle colour parameters (CIE L*, a* and b* values). As denoted by the higher L* and fibre optic probe values and lower subjective muscle score, the longissimus muscle colour was lighter for BS kids than other genotypes. Cooked meat from the BF kids had lower shear force values and better sensory scores compared to other genotypes. A significant (P<0.05) decrease in muscle tenderness was observed from Capretto to Chevon carcasses, whereas cooked meat from these two slaughter weight groups was equally accepted (P>0.05) by the panellists.

Male kids (110) from six goat genotypes, i.e. Boer×Angora (BA), Boer×Feral (BF), Boer×Saanen (BS), Feral×Feral (FF), Saanen×Angora (SA) and Saanen×Feral (SF) and two slaughter weight groups, i.e. Capretto and Chevon (liveweight at slaughter 14–22 and 30–35kg, respectively) were compared for growth, carcass and meat quality characteristics. Due to their better growth rate, kids from BS and SF genotypes reached the required liveweight for slaughter earlier than kids from other genotypes used in the study. Chevon kids had a significantly (P<0.05) lower average daily gain (119g per day) compared to Capretto kids (171g per day). SA, SF and FF kids deposited more internal fat in comparison to kids from other genotypes. The dressing percentage of kids ranged from 51 to 54%, with significant differences between genotypes. BS and SF kids had longer carcasses, while BF kids had larger eye muscle area compared to other genotypes. Goat carcasses had a thin subcutaneous fat cover (1.6–2.2mm). Genotype had a significant (P<0.05) influence on cooking loss, pigment concentration and muscle colour parameters (CIE L∗, a∗ and b∗ values). As denoted by the higher L∗ and fibre optic probe values and lower subjective muscle score, the longissimus muscle colour was lighter for BS kids than other genotypes. Cooked meat from the BF kids had lower shear force values and better sensory scores compared to other genotypes. A significant (P<0.05) decrease in muscle tenderness was observed from Capretto to Chevon carcasses, whereas cooked meat from these two slaughter weight groups was equally accepted (P>0.05) by the panellists.

The dissected carcass composition and fatty acid profiles of intermuscular fat from 110 male goat kids from six genotypes i.e. Boer×Angora (BA), Boer×Feral (BF), Boer×Saanen (BS), Feral×Feral (FF), Saanen×Angora (SA) and Saanen×Feral (SF) and two slaughter weight groups i.e. Capretto and Chevon (liveweight at slaughter 14–22 and 30–35kg, respectively) were compared. Carcass tissue distribution for various genotypes was: muscle (63–66%), fat (10–13%) and bone (21–24%). Genotype significantly (P<0.05) influenced the carcass composition; BA and FF carcasses had significantly higher muscle to bone ratio, while carcasses from BS kids were leaner compared to other genotypes. However, the two slaughter weight groups did not differ significantly (P>0.05) in terms of carcass composition, when compared at the same carcass weight. In the present study, significant (P<0.01) correlations were observed between percentage of muscle, fat and bone in most of the primal cuts and that in the carcass side. The main saturated fatty acids (SFAs) identified were palmitic (16:0) and stearic acid (18:0), while oleic acid (18:1, ω9) was the main unsaturated fatty acid (UFA) in the intermuscular fat from goat kids. There were significant (P<0.05) differences between genotypes in the proportions of individual fatty acids. Adipose tissue from BS kids had significantly higher UFAs (mainly oleic acid) and thus had a significantly lower melting point compared to other genotypes. There were significantly higher proportions of palmitic acid (35%) in the adipose tissue from Capretto kids compared to that from Chevon kids (22%). The concentration of UFAs increased in the adipose tissue from Capretto to Chevon carcasses.