Publications

The purpose of this study was to evaluate under field conditions, the role that right management and vaccination against Escherichia coli plays in the prevention of neonatal kid diarrhoea. To meet this objective, a goat farm of low management standards suffering from a neonatal diarrhoea problem caused by enteropathogenic strains of E. coli was selected. Three experimental groups of new-born kids with their mothers were formed: (a) the kids in Group I were raised under the management conditions already existing in the farm, and served as negative controls, (b) the kids in Group II were raised under improved conditions, including specially prepared warm and draft-free areas for kidding and nursing, and (c) the kids in Group III were raised under the improved conditions of Group II, but were born from does previously vaccinated for E. coli. The three groups were compared with regard to the incidence and duration of diarrhoea, and the mortality of kids. It was shown that, compared to the control group, neonatal morbidity and mortality were both reduced by a factor of 3 in Group II, and by factors of 9.5 and 12.5, respectively, in Group III (P<0.05). Also, the duration of diarrhoea was 3.7 and 12 times shorter in the kids of Groups II and III, respectively, when compared to the control animals (P<0.05). Samples of diarrhoeic faeces from kids in the control group resulted in the isolation of K88 and K99 strains of E. coli. It was concluded that specific vaccination of does followed by improvements in neonatal management may drastically reduce the development of E. coli scours in kids under field conditions.

The purpose of this study was to evaluate under field conditions, the role that right management and vaccination against Escherichia coli plays in the prevention of neonatal kid diarrhoea. To meet this objective, a goat farm of low management standards suffering from a neonatal diarrhoea problem caused by enteropathogenic strains of E. coli was selected. Three experimental groups of new-born kids with their mothers were formed: (a) the kids in Group I were raised under the management conditions already existing in the farm, and served as negative controls, (b) the kids in Group II were raised under improved conditions, including specially prepared warm and draft-free areas for kidding and nursing, and (c) the kids in Group III were raised under the improved conditions of Group II, but were born from does previously vaccinated for E. coli. The three groups were compared with regard to the incidence and duration of diarrhoea, and the mortality of kids. It was shown that, compared to the control group, neonatal morbidity and mortality were both reduced by a factor of 3 in Group II, and by factors of 9.5 and 12.5, respectively, in Group III (P<0.05). Also, the duration of diarrhoea was 3.7 and 12 times shorter in the kids of Groups II and III, respectively, when compared to the control animals (P<0.05). Samples of diarrhoeic faeces from kids in the control group resulted in the isolation of K88 and K99 strains of E. coli. It was concluded that specific vaccination of does followed by improvements in neonatal management may drastically reduce the development of E. coli scours in kids under field conditions.

Individual feed consumption, utilisation, digestion efficiency and growth of 32 Boer goat (BG) kids and 32 South African Mutton Merino (MM) lambs were investigated after weaning. Two pelleted diets (fed to 16 animals per species) with either a low (LE, 9.89MJkg-1 DM) or a high (HE, 12.11MJkg-1 DM) metabolisable energy level were fed individually, ad lib, for either 28 or 56 days. MM had significantly higher average daily gains (ADG) than BG. Within a diet there was no significant difference in feed conversion efficiency (FCE) between BG and MM and only the MM FCE differed between the LE- and HE-diets. BG fed LE digested DM, CP and energy more efficiently and had a higher energy retention than MM fed LE. Neither species, nor diet affected N retention. The average daily gain of the MM on the LE-diet for 28 days was significantly lower than for those on the HE-diet. However, there was no significant difference between the ADG of BG on the high or low energy diets. These trends were similar in the group of animals that were fed for 56 days. These results indicate that Boer goats may be finished on a diet with a lower ME-value than is usually formulated for sheep, without a reduction in performance. This may render the BG economically viable for feedlot finishing.

Individual feed consumption, utilisation, digestion efficiency and growth of 32 Boer goat (BG) kids and 32 South African Mutton Merino (MM) lambs were investigated after weaning. Two pelleted diets (fed to 16 animals per species) with either a low (LE, 9.89MJkg−1 DM) or a high (HE, 12.11MJkg−1 DM) metabolisable energy level were fed individually, ad lib, for either 28 or 56 days. MM had significantly higher average daily gains (ADG) than BG. Within a diet there was no significant difference in feed conversion efficiency (FCE) between BG and MM and only the MM FCE differed between the LE- and HE-diets. BG fed LE digested DM, CP and energy more efficiently and had a higher energy retention than MM fed LE. Neither species, nor diet affected N retention. The average daily gain of the MM on the LE-diet for 28 days was significantly lower than for those on the HE-diet. However, there was no significant difference between the ADG of BG on the high or low energy diets. These trends were similar in the group of animals that were fed for 56 days. These results indicate that Boer goats may be finished on a diet with a lower ME-value than is usually formulated for sheep, without a reduction in performance. This may render the BG economically viable for feedlot finishing.

Eight species of forage, a cool-season perennial (tall fescue (Festuca arundinacea)) and annual grass (winter wheat (Triticum aestivum)), four warm-season perennial grasses (caucasian (Bothriochloa caucasica), plains (B. ischaemum), old world bluestem, bermudagrass (Cynodon dactylon), and eastern gamagrass (Tripsacum dactyloides)), a warm season annual (crabgrass (Digitaria sanguinalis)) and a perennial legume (alfalfa (Medicago sativa)), were each cut at two or three maturities to provide a wide array of quality difference (n=20). Twenty wether goats (Capra hicus) were fed the hays in four different trials using an incomplete block design so that four different goats received each hay. Alfalfa produced the highest (25gkg-1 body weight (BW)) and wheat the lowest (13.6gkg-1 BW) organic matter (OM) intake. A number of the grasses provided less than 20gkg-1 BW OM intake. Digestion of OM was also highest for alfalfa (>715gkg-1) and lowest for bermudagrass (508gkg-1). All measures and expressions of intake and digestibility were better related to ruminating and retention time than to forage chemistry, with the exception of crude protein digestibility. The best equations for predicting intake included a combination of mean retention time and forage acid detergent fiber (ADF) content (reciprocal and quadratic); that for digestibility included permanganate lignin (reciprocal), and the quadratic for ruminating and retention time. Equations for predicting the constraint on intake and digestible organic matter intake produced higher r2 than those for either intake or digestibility. Digestibility of ADF and neutral detergent fiber (NDF) were poorly predicted with either chemistry (r2<=0.20), or ruminating time (r2=0.43), but combinations of permanganate lignin content of NDF, retention and ruminating time produced reasonable equations.

Eight species of forage, a cool-season perennial (tall fescue (Festuca arundinacea)) and annual grass (winter wheat (Triticum aestivum)), four warm-season perennial grasses (caucasian (Bothriochloa caucasica), plains (B. ischaemum), old world bluestem, bermudagrass (Cynodon dactylon), and eastern gamagrass (Tripsacum dactyloides)), a warm season annual (crabgrass (Digitaria sanguinalis)) and a perennial legume (alfalfa (Medicago sativa)), were each cut at two or three maturities to provide a wide array of quality difference (n=20). Twenty wether goats (Capra hicus) were fed the hays in four different trials using an incomplete block design so that four different goats received each hay. Alfalfa produced the highest (25gkg−1 body weight (BW)) and wheat the lowest (13.6gkg−1 BW) organic matter (OM) intake. A number of the grasses provided less than 20gkg−1 BW OM intake. Digestion of OM was also highest for alfalfa (>715gkg−1) and lowest for bermudagrass (508gkg−1). All measures and expressions of intake and digestibility were better related to ruminating and retention time than to forage chemistry, with the exception of crude protein digestibility. The best equations for predicting intake included a combination of mean retention time and forage acid detergent fiber (ADF) content (reciprocal and quadratic); that for digestibility included permanganate lignin (reciprocal), and the quadratic for ruminating and retention time. Equations for predicting the constraint on intake and digestible organic matter intake produced higher r2 than those for either intake or digestibility. Digestibility of ADF and neutral detergent fiber (NDF) were poorly predicted with either chemistry (r2≤0.20), or ruminating time (r2=0.43), but combinations of permanganate lignin content of NDF, retention and ruminating time produced reasonable equations.

Three experiments were conducted to evaluate sunflower seed meal (SFM) as a substitute for soybean meal (SBOM) in rations of fattening Awassi lambs and milking ewes. In the first experiment, 12 Awassi lambs were assigned into four groups to measure the digestibility of the SFM and experimental rations. The control group ration (1) contained SBOM while in the other two rations, SFM replaced SBOM at a level of 50% (2) and 100% (3), respectively. The fourth group was fed only SFM. No significant differences were observed between lambs fed the experimental rations in digestibilities of DM, OM, CP, CF, NDF, ADF or N balance. NFE had a higher (P<0.05) digestibility for ration 1 than ration 2. In the second experiment, the voluntary feed intake was measured for the Awassi ewes during milking and dry period using 36 Awassi lactating ewes. For the two stages there were no significant differences between rations in voluntary intake. Milk yields (kg/herd per day), milk fat (%) and milk total solids (%) were not different among groups. In the third experiment, 42 lambs (males and females) were divided randomly into three treatment groups. Rations were the same experimental rations in the digestibility study. There were no significant differences in the average final BW, ADG and average feed conversion ratios (FCR) among the treatments. These experiments showed that SFM could replace SBOM as a protein source in rations of fattening Awassi lambs and milking Awassi ewes.

Three experiments were conducted to evaluate sunflower seed meal (SFM) as a substitute for soybean meal (SBOM) in rations of fattening Awassi lambs and milking ewes. In the first experiment, 12 Awassi lambs were assigned into four groups to measure the digestibility of the SFM and experimental rations. The control group ration (1) contained SBOM while in the other two rations, SFM replaced SBOM at a level of 50% (2) and 100% (3), respectively. The fourth group was fed only SFM. No significant differences were observed between lambs fed the experimental rations in digestibilities of DM, OM, CP, CF, NDF, ADF or N balance. NFE had a higher (P<0.05) digestibility for ration 1 than ration 2. In the second experiment, the voluntary feed intake was measured for the Awassi ewes during milking and dry period using 36 Awassi lactating ewes. For the two stages there were no significant differences between rations in voluntary intake. Milk yields (kg/herd per day), milk fat (%) and milk total solids (%) were not different among groups. In the third experiment, 42 lambs (males and females) were divided randomly into three treatment groups. Rations were the same experimental rations in the digestibility study. There were no significant differences in the average final BW, ADG and average feed conversion ratios (FCR) among the treatments. These experiments showed that SFM could replace SBOM as a protein source in rations of fattening Awassi lambs and milking Awassi ewes.

A total of 209 milk samples were collected from the udder halves of 178 native dairy ewes at 2 weeks after lambing until the 10th week postpartum. Those which were classified by bacterial culture and California Mastitis Test (CMT) as positive, were deemed to have glands with subclinical mastitis (SCM). The periodic prevalence rate of SCM was 39%. The most common bacterial isolates from SCM cases were coagulase negative staphylococci (41%), Bacillus cereus (33%), Staphylococcus aureus (22%) and Streptococcus spp. (4%). The mean activity of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were higher in milk from SCM udders than in milk from healthy udders (P<0.01). There were no significant differences in blood serum LDH, ALP and aspartate aminotransferase (AST) of healthy and subclinical mastitic ewes. The increment in LDH and ALP in milk of udders shows the presence of tissue damage provoked by SCM. Thus, these parameters might be suitable for use in the early diagnosis of subclinical mastitis in ewes.

A total of 209 milk samples were collected from the udder halves of 178 native dairy ewes at 2 weeks after lambing until the 10th week postpartum. Those which were classified by bacterial culture and California Mastitis Test (CMT) as positive, were deemed to have glands with subclinical mastitis (SCM). The periodic prevalence rate of SCM was 39%. The most common bacterial isolates from SCM cases were coagulase negative staphylococci (41%), Bacillus cereus (33%), Staphylococcus aureus (22%) and Streptococcus spp. (4%). The mean activity of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were higher in milk from SCM udders than in milk from healthy udders (P<0.01). There were no significant differences in blood serum LDH, ALP and aspartate aminotransferase (AST) of healthy and subclinical mastitic ewes. The increment in LDH and ALP in milk of udders shows the presence of tissue damage provoked by SCM. Thus, these parameters might be suitable for use in the early diagnosis of subclinical mastitis in ewes.