Publications

Antigen recognition patterns (Western blotting) and lymphoproliferative response (local and peripheral) have been determined in lambs immunised and partially protected against haemonchosis with p26/23, a purified somatic fraction of Haemonchus contortus. Immunoprotective response induced by p26/23 was accompanied by both specific lymphoproliferative response and serum anti-Haemonchus antibodies. Western blotting showed an extensive reactivity of sera from p26/23 vaccinated lambs with peptides from adult soluble extract of the parasite at 23–26, 34–55, 55 and 65kDa levels. Immunised lambs exhibited, after challenge, significantly higher lymphoproliferative responses (systemic and local) than all other animals groups (unvaccinated, adjuvant control animals, uninfected lambs). Challenge infection was accompanied by significant weight increases of abomasal lymph nodes; in addition specific peripheral and abomasal cell responses were correlated.

Antigen recognition patterns (Western blotting) and lymphoproliferative response (local and peripheral) have been determined in lambs immunised and partially protected against haemonchosis with p26/23, a purified somatic fraction of Haemonchus contortus. Immunoprotective response induced by p26/23 was accompanied by both specific lymphoproliferative response and serum anti-Haemonchus antibodies. Western blotting showed an extensive reactivity of sera from p26/23 vaccinated lambs with peptides from adult soluble extract of the parasite at 23–26, 34–55, 55 and 65kDa levels. Immunised lambs exhibited, after challenge, significantly higher lymphoproliferative responses (systemic and local) than all other animals groups (unvaccinated, adjuvant control animals, uninfected lambs). Challenge infection was accompanied by significant weight increases of abomasal lymph nodes; in addition specific peripheral and abomasal cell responses were correlated.

In an attempt to identify factor(s) that influence in vitro development of preantral follicles (PFs) in sheep, small (40–60μm in diameter) and large (61–100μm in diameter) PFs were cultured for 6 days in tissue culture medium (TCM 199) supplemented with transforming growth factor-α (TGF-α), insulin-like growth factor-II (IGF-II), epidermal growth factor (EGF) or follicle stimulating hormone (FSH). Increase in follicle diameter, oocyte diameter, induction of new DNA synthesis in the follicular cells and increase in number of follicular cells per follicle were measured as the indicators of development. Only EGF supplemented medium increased the follicle diameter, number of follicular cells and also induced intense DNA synthesis in both small and large PFs. TGF-α, IGF-II and FSH on the other hand were able to stimulate intense DNA synthesis only in large PFs. None of the supplemented media caused an increase in oocyte diameter. It is proposed that EGF stimulates the development of preantral follicles of sheep up to 100μm in diameter.

In an attempt to identify factor(s) that influence in vitro development of preantral follicles (PFs) in sheep, small (40–60μm in diameter) and large (61–100μm in diameter) PFs were cultured for 6 days in tissue culture medium (TCM 199) supplemented with transforming growth factor-α (TGF-α), insulin-like growth factor-II (IGF-II), epidermal growth factor (EGF) or follicle stimulating hormone (FSH). Increase in follicle diameter, oocyte diameter, induction of new DNA synthesis in the follicular cells and increase in number of follicular cells per follicle were measured as the indicators of development. Only EGF supplemented medium increased the follicle diameter, number of follicular cells and also induced intense DNA synthesis in both small and large PFs. TGF-α, IGF-II and FSH on the other hand were able to stimulate intense DNA synthesis only in large PFs. None of the supplemented media caused an increase in oocyte diameter. It is proposed that EGF stimulates the development of preantral follicles of sheep up to 100μm in diameter.

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.