Publications

The present study suggests the existence of an association between milk production traits and genetic polymorphisms at the growth hormone (GH) gene in the Portuguese indigenous Serrana goat. The DNA from 229 animals of two ecotypes (Jarmelista and Ribatejano) was analysed by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique revealing a high degree of genetic polymorphism at the goat GH (gGH) gene. Two conformation patterns were detected in exons 1 and 2, 6 in exon 3, 10 in exon 4 and 5 in exon 5. The evaluation of an association effect between these SSCP patterns with milk, fat and protein yields and fat and protein percentages suggests a positive effect of pattern A/B of exon 4 for Ribatejano ecotype and of pattern A/B of exon 2 for Jarmelista ecotype with milk yield (P<0.05) and of pattern A/B of exon 1 and pattern B/B of exon 2 with protein percentage (P<0.05) for Ribatejano ecotype. The results support the hints suggested by previous studies of the importance of the gGH gene as a candidate gene for marker-assisted selection in goat breeds and suggest that exon 4 is a preferential target for further investigation on mutations that influence milk yield variation.

The present study suggests the existence of an association between milk production traits and genetic polymorphisms at the growth hormone (GH) gene in the Portuguese indigenous Serrana goat. The DNA from 229 animals of two ecotypes (Jarmelista and Ribatejano) was analysed by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique revealing a high degree of genetic polymorphism at the goat GH (gGH) gene. Two conformation patterns were detected in exons 1 and 2, 6 in exon 3, 10 in exon 4 and 5 in exon 5. The evaluation of an association effect between these SSCP patterns with milk, fat and protein yields and fat and protein percentages suggests a positive effect of pattern A/B of exon 4 for Ribatejano ecotype and of pattern A/B of exon 2 for Jarmelista ecotype with milk yield (P<0.05) and of pattern A/B of exon 1 and pattern B/B of exon 2 with protein percentage (P<0.05) for Ribatejano ecotype. The results support the hints suggested by previous studies of the importance of the gGH gene as a candidate gene for marker-assisted selection in goat breeds and suggest that exon 4 is a preferential target for further investigation on mutations that influence milk yield variation.

The study was to determine the prevalent diseases of three native Nigeria goat breeds reared in the same environment for a period of 5 years (1995–1999). The indigenous goat breeds used were the Red Sokoto (RS), West African Dwarf (WAD) and their crossbreeds (CB). The prevalent diagnoses included mange, tick and flea infestations, helminthiasis, pneumonia, peste des petits ruminants (PPR), orf, abortion/stillbirth and premature delivery. Only the WAD had prevalence of helminthiasis, orf and premature delivery. The CB group had greater prevalence (P<0.05) of tick and flea infestations and of abortion/stillbirth than the other breeds. Age group had no influence on the prevalence of most of the diagnosed diseases. The kids were the major age group affected by orf. Seasonal variation in disease prevalence also was observed with mange and helminthiasis occurring during early- and late-rainy seasons. Seasons and genotype are therefore important factors affecting the prevalence and susceptibility of goats to diseases in the equatorial zone of southeastern Nigeria.

The study was to determine the prevalent diseases of three native Nigeria goat breeds reared in the same environment for a period of 5 years (1995–1999). The indigenous goat breeds used were the Red Sokoto (RS), West African Dwarf (WAD) and their crossbreeds (CB). The prevalent diagnoses included mange, tick and flea infestations, helminthiasis, pneumonia, peste des petits ruminants (PPR), orf, abortion/stillbirth and premature delivery. Only the WAD had prevalence of helminthiasis, orf and premature delivery. The CB group had greater prevalence (P<0.05) of tick and flea infestations and of abortion/stillbirth than the other breeds. Age group had no influence on the prevalence of most of the diagnosed diseases. The kids were the major age group affected by orf. Seasonal variation in disease prevalence also was observed with mange and helminthiasis occurring during early- and late-rainy seasons. Seasons and genotype are therefore important factors affecting the prevalence and susceptibility of goats to diseases in the equatorial zone of southeastern Nigeria.

Data from 19 feeding trials conducted on growing sheep from different institutes across India were subjected to regression analysis to derive requirements of TDN, CP and DCP for maintenance and body weight gain. Maintenance requirements for TDN, CP and DCP were 37.0, 6.68 and 4.43g/kg W0.75, respectively for the BW range of 7–15kg, and the corresponding maintenance requirements for the BW range of 15.1–30kg were 35.3, 6.98 and 4.49g. The corresponding requirements for 1g gain in BW were 0.91, 0.47, and 0.31g, for 7–15kg BW and 1.21, 0.43 and 0.30g, respectively for 15–30kg BW range. Regression equations had high R2 values (0.59–0.84) and the equations (F value) as well as coefficients were highly significant (P<0.001). Regressed values were used to develop feeding standards. Derived values matched well with the actual intake versus performance of animals under diverse feeding conditions. The new standards so derived predicted requirements and intake of nutrients for different production levels better than existing feeding standards; as these are based on a more thorough analysis of a larger database, the new feeding standards will be appropriate for wide use in India.

Data from 19 feeding trials conducted on growing sheep from different institutes across India were subjected to regression analysis to derive requirements of TDN, CP and DCP for maintenance and body weight gain. Maintenance requirements for TDN, CP and DCP were 37.0, 6.68 and 4.43g/kg W0.75, respectively for the BW range of 7–15kg, and the corresponding maintenance requirements for the BW range of 15.1–30kg were 35.3, 6.98 and 4.49g. The corresponding requirements for 1g gain in BW were 0.91, 0.47, and 0.31g, for 7–15kg BW and 1.21, 0.43 and 0.30g, respectively for 15–30kg BW range. Regression equations had high R2 values (0.59–0.84) and the equations (F value) as well as coefficients were highly significant (P<0.001). Regressed values were used to develop feeding standards. Derived values matched well with the actual intake versus performance of animals under diverse feeding conditions. The new standards so derived predicted requirements and intake of nutrients for different production levels better than existing feeding standards; as these are based on a more thorough analysis of a larger database, the new feeding standards will be appropriate for wide use in India.

Breeding objectives were developed for meat sheep in smallholder production circumstances in the tropics. The traits considered were litter size, lambing frequency, pre-weaning, and post-weaning lamb survival to 12 months, ewe survival, lamb live weight at 12-month, mature ewe live weight, consumable meat, kg of manure DM sold per ewe per year and residual DM feed intake. Three evaluation situations were considered: (i) base with constant number of ewes, (ii) fixed feed resource and (iii) setting feed costs to zero. Sensitivity analysis of economic values to price levels of inputs and meat production was carried out. The fixed feed resource situation appropriately describes smallholder production circumstances. In the base situation, meat production accounted for about 88% of revenue and manure the remaining 12%. Variable costs represented about 95% of the total cost. For the fixed feed resource situation, economic values (US$ per ewe per year) were 12.94 for litter size, 10.18 for lambing frequency, 0.19 for pre-weaning lamb survival, 0.24 for post-weaning lamb survival, 0.36 for ewe survival, 1.02 for 12-month lamb live weight, 0.14 for mature ewe live weight, 0.51 for consumable meat, 0.08 for kg of manure DM sold (per ewe per year) and -0.04 for residual DM feed intake. Litter size and lambing frequency were the most important traits in a breeding objective for smallholder production. Relative to the base situation, setting feed costs to zero had similar results as the situation with restricted feed resource but resulted in larger differences. Sensitivity analysis of economic weights to changes in prices and production circumstances indicated that future economic values for traits might change dependent on levels of output and prices. The exceptions, with regard to changes in meat price are kg of manure DM sold per ewe per year and residual DM feed intake, and with regard to feed costs are consumable meat and kg of manure DM sold per ewe per year. Economic values for 12-month lamb live weight, mature ewe live weight, consumable meat, kg of manure DM sold per ewe per year and residual DM feed intake were not sensitive to changes in management and marketing circumstances. Caution is recommended when the breeding objectives presented here are applied not to disadvantage smallholders in poor climatic years, when farmers are at their most vulnerable situation.

Breeding objectives were developed for meat sheep in smallholder production circumstances in the tropics. The traits considered were litter size, lambing frequency, pre-weaning, and post-weaning lamb survival to 12 months, ewe survival, lamb live weight at 12-month, mature ewe live weight, consumable meat, kg of manure DM sold per ewe per year and residual DM feed intake. Three evaluation situations were considered: (i) base with constant number of ewes, (ii) fixed feed resource and (iii) setting feed costs to zero. Sensitivity analysis of economic values to price levels of inputs and meat production was carried out. The fixed feed resource situation appropriately describes smallholder production circumstances. In the base situation, meat production accounted for about 88% of revenue and manure the remaining 12%. Variable costs represented about 95% of the total cost. For the fixed feed resource situation, economic values (US$ per ewe per year) were 12.94 for litter size, 10.18 for lambing frequency, 0.19 for pre-weaning lamb survival, 0.24 for post-weaning lamb survival, 0.36 for ewe survival, 1.02 for 12-month lamb live weight, 0.14 for mature ewe live weight, 0.51 for consumable meat, 0.08 for kg of manure DM sold (per ewe per year) and −0.04 for residual DM feed intake. Litter size and lambing frequency were the most important traits in a breeding objective for smallholder production. Relative to the base situation, setting feed costs to zero had similar results as the situation with restricted feed resource but resulted in larger differences. Sensitivity analysis of economic weights to changes in prices and production circumstances indicated that future economic values for traits might change dependent on levels of output and prices. The exceptions, with regard to changes in meat price are kg of manure DM sold per ewe per year and residual DM feed intake, and with regard to feed costs are consumable meat and kg of manure DM sold per ewe per year. Economic values for 12-month lamb live weight, mature ewe live weight, consumable meat, kg of manure DM sold per ewe per year and residual DM feed intake were not sensitive to changes in management and marketing circumstances. Caution is recommended when the breeding objectives presented here are applied not to disadvantage smallholders in poor climatic years, when farmers are at their most vulnerable situation.

Spanish wether and doeling kids (4.5 months of age; 13.4kg initial BW) were used to determine influences of different quality diets consumed continuously or after a lower quality diet on characteristics of growth. The experiment consisted of two 9-week periods. Diets were low quality forage (L, prairie hay supplemented with soybean meal), high quality forage (H, dehydrated alfalfa pellets) and 70% concentrate (C). Kids on two treatments consumed L in Period 1, with half switched to C and half to H in Period 2 (LC and LH, respectively). The CC treatment entailed C consumption in both periods, and HH kids were fed H in both periods. For HC, H was fed in Period 1 followed by C in Period 2. DM intake ranked (P<0.05) LC and LH

Spanish wether and doeling kids (4.5 months of age; 13.4kg initial BW) were used to determine influences of different quality diets consumed continuously or after a lower quality diet on characteristics of growth. The experiment consisted of two 9-week periods. Diets were low quality forage (L, prairie hay supplemented with soybean meal), high quality forage (H, dehydrated alfalfa pellets) and 70% concentrate (C). Kids on two treatments consumed L in Period 1, with half switched to C and half to H in Period 2 (LC and LH, respectively). The CC treatment entailed C consumption in both periods, and HH kids were fed H in both periods. For HC, H was fed in Period 1 followed by C in Period 2. DM intake ranked (P<0.05) LC and LH

The effects of dosage of follicle stimulating hormone (FSH), vehicle and time of injection on ovulation rate and prolificacy were evaluated during the anestrous season. Ewes on four farms (n=445) were treated with a CIDR-G® device for 5 days and exposed to rams upon removal of the insert (CRRI, day 0). A 3×2×2 factorial arrangement tested effects of dosage of FSH (Folltropin®; 0, 42 or 68mg NIH-FSH-P1), vehicle (saline:propylene glycol 1:4, v/v [PGL], or 50% polyvinylpyrrolidone K 29–32 [PVP]) and time of injection (12 or 36h before CRRI). Follicular growth was monitored by ultrasonography in four ewes per treatment at injection of FSH, at CRRI, and on days 1–3 post-CRRI. All ewes were examined by ultrasonography on days 10–14 for ovulation rate, and on days 26–31 and 46–51 for pregnancy and number of embryos. The largest follicle (F1) increased in diameter (mm) between FSH injection (5.3±0.1) and day 1 (6.1±0.1; P<0.01). The F1 was larger at CRRI (P≤0.05) in ewes receiving 42 than 0mg FSH, and 68 than 42mg FSH. The F2 increased in diameter (P<0.05) from FSH injection (4.7±0.2) to CRRI (5.2±0.2) and to day 1 (5.8±0.2), but was not affected by treatment. Number of small follicles (≤4mm) did not differ with time or treatment. Number of medium follicles (5mm) declined (P<0.05) between FSH (1.5±0.2) and days 1 (0.8±0.2), 2 (0.9±0.2), and 3 (0.5±0.2). Number of large follicles (≥6mm) increased from FSH (0.6±0.3) to CRRI (1.4±0.3; P<0.05), and day 1 (2.3±0.3; P<0.05), then declined by day 3 (0.6±0.3; P<0.05). There were more large follicles at CRRI (P<0.05) with 68mg (2.1±0.3) or 42mg (1.6±0.2) than 0mg (0.5±0.4) FSH. Ovulation rate (mean 2.12±0.05) increased with FSH given 12h, but not 36h before CRRI (dosage × time, P<0.05). Estrous response, conception rate, percentage of ewes lambing or prolificacy did not differ. However, number of corpora lutea not represented by embryos increased with dosage of FSH (P<0.01; 0.25±0.14, 0.55±0.09, 0.71±0.09 for ewes treated with 0, 42, and 68mg FSH, respectively).

The effects of dosage of follicle stimulating hormone (FSH), vehicle and time of injection on ovulation rate and prolificacy were evaluated during the anestrous season. Ewes on four farms (n=445) were treated with a CIDR-G® device for 5 days and exposed to rams upon removal of the insert (CRRI, day 0). A 3×2×2 factorial arrangement tested effects of dosage of FSH (Folltropin®; 0, 42 or 68mg NIH-FSH-P1), vehicle (saline:propylene glycol 1:4, v/v [PGL], or 50% polyvinylpyrrolidone K 29–32 [PVP]) and time of injection (12 or 36h before CRRI). Follicular growth was monitored by ultrasonography in four ewes per treatment at injection of FSH, at CRRI, and on days 1–3 post-CRRI. All ewes were examined by ultrasonography on days 10–14 for ovulation rate, and on days 26–31 and 46–51 for pregnancy and number of embryos. The largest follicle (F1) increased in diameter (mm) between FSH injection (5.3±0.1) and day 1 (6.1±0.1; P<0.01). The F1 was larger at CRRI (P<=0.05) in ewes receiving 42 than 0mg FSH, and 68 than 42mg FSH. The F2 increased in diameter (P<0.05) from FSH injection (4.7±0.2) to CRRI (5.2±0.2) and to day 1 (5.8±0.2), but was not affected by treatment. Number of small follicles (<=4mm) did not differ with time or treatment. Number of medium follicles (5mm) declined (P<0.05) between FSH (1.5±0.2) and days 1 (0.8±0.2), 2 (0.9±0.2), and 3 (0.5±0.2). Number of large follicles (>=6mm) increased from FSH (0.6±0.3) to CRRI (1.4±0.3; P<0.05), and day 1 (2.3±0.3; P<0.05), then declined by day 3 (0.6±0.3; P<0.05). There were more large follicles at CRRI (P<0.05) with 68mg (2.1±0.3) or 42mg (1.6±0.2) than 0mg (0.5±0.4) FSH. Ovulation rate (mean 2.12±0.05) increased with FSH given 12h, but not 36h before CRRI (dosage × time, P<0.05). Estrous response, conception rate, percentage of ewes lambing or prolificacy did not differ. However, number of corpora lutea not represented by embryos increased with dosage of FSH (P<0.01; 0.25±0.14, 0.55±0.09, 0.71±0.09 for ewes treated with 0, 42, and 68mg FSH, respectively).

A two by two factorial design including natural helminth infections (dewormed ‘D’ or not dewormed ‘ND’) and different levels of diet (basal ‘B’ or basal diet plus supplement ‘S’) was used to assess the effect of helminth infections and plane of nutrition on health and productivity of F1 (West African Dwarf (WAD) × Sahelian) crosses. The pasture composed the basal diet and supplemented animals received cottonseed and rice bran. Feed composition analysis revealed that the pasture did not provide sufficient nutrients for reproduction requirements. Feed supplementation had a significant effect on weight gain of does during pregnancy and lactation, and milk off-take was significantly higher in supplemented does compared to non-supplemented ones (31.3±2.5l versus 17.7±2.5l respectively, P<0.01). A peri-parturient rise in strongyle egg output was noted, and diet supplementation tended to reduce faecal egg count and to increase packed cell volume (PCV), mainly during the dry season. Deworming had a significant effect on red blood cell (RBC) count, PCV and haemoglobin (Hb) concentration, mainly during the period of peak strongyle egg output (season × deworming: P<0.001 for RBC and PCV and P<0.05 for Hb). Helminth infections combined with a basal diet seriously affected weight gain but the interaction of deworming and diet was not significant. In groups receiving the basal diet, dewormed animals had a significantly higher milk yield than those that were not dewormed (23.5±3.3l versus 12.0±3.7l, respectively; interaction diet × deworming: P<0.05). The higher daily weight gains of offspring born from dewormed does might be explained by the fact that, in addition to the effect of deworming on milk yield in animals receiving basal diet, the kids were less exposed to helminth eggs, whereas does that were not dewormed constituted a greater source of helminth infection for their kids.

A two by two factorial design including natural helminth infections (dewormed ‘D’ or not dewormed ‘ND’) and different levels of diet (basal ‘B’ or basal diet plus supplement ‘S’) was used to assess the effect of helminth infections and plane of nutrition on health and productivity of F1 (West African Dwarf (WAD) × Sahelian) crosses. The pasture composed the basal diet and supplemented animals received cottonseed and rice bran. Feed composition analysis revealed that the pasture did not provide sufficient nutrients for reproduction requirements. Feed supplementation had a significant effect on weight gain of does during pregnancy and lactation, and milk off-take was significantly higher in supplemented does compared to non-supplemented ones (31.3±2.5l versus 17.7±2.5l respectively, P<0.01). A peri-parturient rise in strongyle egg output was noted, and diet supplementation tended to reduce faecal egg count and to increase packed cell volume (PCV), mainly during the dry season. Deworming had a significant effect on red blood cell (RBC) count, PCV and haemoglobin (Hb) concentration, mainly during the period of peak strongyle egg output (season × deworming: P<0.001 for RBC and PCV and P<0.05 for Hb). Helminth infections combined with a basal diet seriously affected weight gain but the interaction of deworming and diet was not significant. In groups receiving the basal diet, dewormed animals had a significantly higher milk yield than those that were not dewormed (23.5±3.3l versus 12.0±3.7l, respectively; interaction diet × deworming: P<0.05). The higher daily weight gains of offspring born from dewormed does might be explained by the fact that, in addition to the effect of deworming on milk yield in animals receiving basal diet, the kids were less exposed to helminth eggs, whereas does that were not dewormed constituted a greater source of helminth infection for their kids.

Eight yearling Boer×Spanish wether goats (36.6±2.3kg average initial BW) with ruminal and duodenal cannulae were used in an experiment with two simultaneous 4×4 Latin squares to study effects of dietary level of CP, the ratio of ruminally degraded intake N or protein (DIP) to TDN and source of supplemental DIP on site of digestion with a high concentrate diet. Diets were formulated to be (DM basis) 9.2% CP, without inclusion of urea (U0) or soybean meal (SBM; S0); 11.3%, CP achieved with 0.73% urea (U1) or 4.48% SBM (S1); 13.3% CP, via use of 1.46% urea (U2) or 8.90% SBM (S2); or 15.2% CP, derived through use of 2.16% urea (U3) or 13.2% SBM (S3). The ratio of DIP:TDN was 0.073, 0.104, 0.136, 0.167, 0.073, 0.093, 0.113 and 0.132 for U0, U1, U2, U3, S0, S1, S2 and S3, respectively. Diets contained 30% cottonseed hulls and were corn-based and fed at 2% BW (DM basis). Apparent ruminal N digestibility increased quadratically as level of supplemental CP rose (−71.6, −39.9, −20.5, 8.5, −60.3, −12.5, −8.4 and −3.5% for U0, U1, U2, U3, S0, S1, S2 and S3, respectively; S.E.=6.6). Microbial OM and N flows to duodenum decreased linearly as CP level increased. Ruminal and total tract NDF digestibilities (e.g. total tract: 51.3, 57.6, 57.7, 57.4, 49.7, 52.3, 53.2 and 53.2% for U0, U1, U2, U3, S0, S1, S2 and S3, respectively) increased linearly and tended to change quadratically as CP level increased. In conclusion, a dietary CP concentration of 11–13% and DIP:TDN ratio of 0.10–0.11 were adequate for maximal total tract OM digestibility in meat goats consuming a corn-based, high concentrate diet, regardless of supplementation with a source of non-protein versus natural protein, although magnitudes of difference in digestibility with lower levels were not marked. A dietary CP concentration of 9–10% and ratio of DIP to TDN of 0.073 were sufficient for highest microbial protein production. With ample tissue N reserves, the ability of meat goats to recycle N may preclude realization of substantial benefits from supplementing high concentrate diets around 9% CP with additional DIP, and high concentrate diets appear to satisfy microbial needs for non-ammonia nitrogenous compounds.

Eight yearling Boer×Spanish wether goats (36.6±2.3kg average initial BW) with ruminal and duodenal cannulae were used in an experiment with two simultaneous 4×4 Latin squares to study effects of dietary level of CP, the ratio of ruminally degraded intake N or protein (DIP) to TDN and source of supplemental DIP on site of digestion with a high concentrate diet. Diets were formulated to be (DM basis) 9.2% CP, without inclusion of urea (U0) or soybean meal (SBM; S0); 11.3%, CP achieved with 0.73% urea (U1) or 4.48% SBM (S1); 13.3% CP, via use of 1.46% urea (U2) or 8.90% SBM (S2); or 15.2% CP, derived through use of 2.16% urea (U3) or 13.2% SBM (S3). The ratio of DIP:TDN was 0.073, 0.104, 0.136, 0.167, 0.073, 0.093, 0.113 and 0.132 for U0, U1, U2, U3, S0, S1, S2 and S3, respectively. Diets contained 30% cottonseed hulls and were corn-based and fed at 2% BW (DM basis). Apparent ruminal N digestibility increased quadratically as level of supplemental CP rose (-71.6, -39.9, -20.5, 8.5, -60.3, -12.5, -8.4 and -3.5% for U0, U1, U2, U3, S0, S1, S2 and S3, respectively; S.E.=6.6). Microbial OM and N flows to duodenum decreased linearly as CP level increased. Ruminal and total tract NDF digestibilities (e.g. total tract: 51.3, 57.6, 57.7, 57.4, 49.7, 52.3, 53.2 and 53.2% for U0, U1, U2, U3, S0, S1, S2 and S3, respectively) increased linearly and tended to change quadratically as CP level increased. In conclusion, a dietary CP concentration of 11–13% and DIP:TDN ratio of 0.10–0.11 were adequate for maximal total tract OM digestibility in meat goats consuming a corn-based, high concentrate diet, regardless of supplementation with a source of non-protein versus natural protein, although magnitudes of difference in digestibility with lower levels were not marked. A dietary CP concentration of 9–10% and ratio of DIP to TDN of 0.073 were sufficient for highest microbial protein production. With ample tissue N reserves, the ability of meat goats to recycle N may preclude realization of substantial benefits from supplementing high concentrate diets around 9% CP with additional DIP, and high concentrate diets appear to satisfy microbial needs for non-ammonia nitrogenous compounds.