Emiliano Raffrenato
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Emiliano Raffrenato has a total of 106 co-authors. Here are the top co-authors by number of shared publications:
- Cletos Mapiye
Stellenbosch Univerity
6 shared publications - Giulia Esposito
Department of Animal Sciences, Stellenbosch University, Stellenbosch 7600, South Africa
4 shared publications - Michael E. Van Amburgh
Department of Animal Science, Cornell University, Ithaca, NY 14853, USA
4 shared publications - Kennedy Dzama
Department of Animal Sciences Stellenbosch University Private Bag X1 7602 Matieland South Africa
3 shared publications - Louwrens Christiaan Hoffman
Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Brisbane, QLD 4072, Australia
3 shared publications - Lucia Bailoni
Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, PD, Italy
3 shared publications
Latest Publications
- Open Access
- 1 November 2025
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 108 (11) , 12164-12179
Effects of Saccharomyces cerevisiae boulardii on preweaning calf performance in the presence and absence of chronic stress
The objectives of this study were to evaluate the effects of a Saccharomyces cerevisiae boulardii CNCM I-1079 probiotic yeast product (PRO) on the performance, health, and stress resilience of Holstein heifer calves in the presence and absence of chronic stress (CS). Chronic stress was simulated by inconsistency in the delivery of the calf milk replacer. A total of 80 Holstein heifer calves were randomly assigned to 1 of 4 treatments at 5 d of age: calves that were not exposed to any CS and did not receive PRO (noCS-noPRO, n = 20), calves exposed to CS and not receiving PRO (CS-noPRO, n = 20), calves not exposed to any CS and that did receive PRO (noCS-PRO, n = 20), or calves that were exposed to CS and received PRO (CS-PRO, n = 20). Starter intake was recorded daily, and BW were measured weekly to determine calf performance. Fecal scores were recorded weekly, and blood samples were obtained every 2 wk to monitor calf health. Additionally, fecal glucocorticoid metabolites (fGCM) were measured to identify stress responses in calves. Calves that were exposed to CS consumed less starter feed and had lower mean BW compared with calves that were not. Calves receiving PRO showed an improvement in calf starter intake and were able to mitigate the effects of CS on BW. It was found that PRO influenced the lymphocyte count by increasing it over time, and CS influenced the neutrophil count by increasing it. Calves that were continuously exposed to inconsistent diet distribution had higher mean fGCM during the preweaning phase, whereas calves receiving PRO had lower mean fGCM concentrations. In conclusion, inconsistent diet distribution likely exposed calves to CS, as it was shown to repeatedly induce stress responses in calves. Calves receiving PRO were able to mitigate the negative effects of CS; however, no benefits of PRO were observed in well-managed calves not exposed to chronic stress. Therefore, we predict that PRO administration may help promote appropriate coping behaviors and stress resilience in calves and can be used as a supportive strategy during challenging times.
- 1 November 2025
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 108 (11) , 12164-12179
Open AccessEffects of Saccharomyces cerevisiae boulardii on preweaning calf performance in the presence and absence of chronic stress
The objectives of this study were to evaluate the effects of a Saccharomyces cerevisiae boulardii CNCM I-1079 probiotic yeast product (PRO) on the performance, health, and stress resilience of Holstein heifer calves in the presence and absence of chronic stress (CS). Chronic stress was simulated by inconsistency in the delivery of the calf milk replacer. A total of 80 Holstein heifer calves were randomly assigned to 1 of 4 treatments at 5 d of age: calves that were not exposed to any CS and did not receive PRO (noCS-noPRO, n = 20), calves exposed to CS and not receiving PRO (CS-noPRO, n = 20), calves not exposed to any CS and that did receive PRO (noCS-PRO, n = 20), or calves that were exposed to CS and received PRO (CS-PRO, n = 20). Starter intake was recorded daily, and BW were measured weekly to determine calf performance. Fecal scores were recorded weekly, and blood samples were obtained every 2 wk to monitor calf health. Additionally, fecal glucocorticoid metabolites (fGCM) were measured to identify stress responses in calves. Calves that were exposed to CS consumed less starter feed and had lower mean BW compared with calves that were not. Calves receiving PRO showed an improvement in calf starter intake and were able to mitigate the effects of CS on BW. It was found that PRO influenced the lymphocyte count by increasing it over time, and CS influenced the neutrophil count by increasing it. Calves that were continuously exposed to inconsistent diet distribution had higher mean fGCM during the preweaning phase, whereas calves receiving PRO had lower mean fGCM concentrations. In conclusion, inconsistent diet distribution likely exposed calves to CS, as it was shown to repeatedly induce stress responses in calves. Calves receiving PRO were able to mitigate the negative effects of CS; however, no benefits of PRO were observed in well-managed calves not exposed to chronic stress. Therefore, we predict that PRO administration may help promote appropriate coping behaviors and stress resilience in calves and can be used as a supportive strategy during challenging times.
- Open Access
Chemical Characterization of 29 Industrial Hempseed (Cannabis sativa L.) Varieties
Hemp is considered one of the potential novel crops for human and animal nutrition. This study aimed to determine the complete chemical composition of 29 different varieties of whole hempseeds. Fatty acid composition, amino acid profile, mineral composition, and cannabinoids content were also evaluated. All hempseed varieties were milled to obtain whole hempseed flour. Differences between hempseed varieties were significant (p < 0.05) for all measured parameters. Proximate composition results showed that crude protein and fat contents varied from 21.6–28.9% and 21.1–35.7%, respectively. Fatty acid profiles revealed that the three major fatty acids were linoleic acid (52.79–57.13%) followed by α-linolenic acid (12.62–20.24%), and oleic acid (11.08–17.81%). All essential amino acids were detected in all varieties, with arginine (12.66–17.56 mg/100 g protein) present in abundance, whereas lysine was limiting. Substantial differences were found in the mineral content, and potassium (509.96–1182.65 mg/100 g) and iron (5.06–32.37 mg/100 mg) were the main macro- and microminerals found. All cannabinoids were found in small traces and tetrahydrocannabidiol (THC) was only detected in five varieties. To conclude, the nutritional composition of hempseeds with hull makes them suitable to be added into the diets of humans or animals as a highly beneficial novel ingredient.
Open AccessChemical Characterization of 29 Industrial Hempseed (Cannabis sativa L.) Varieties
Hemp is considered one of the potential novel crops for human and animal nutrition. This study aimed to determine the complete chemical composition of 29 different varieties of whole hempseeds. Fatty acid composition, amino acid profile, mineral composition, and cannabinoids content were also evaluated. All hempseed varieties were milled to obtain whole hempseed flour. Differences between hempseed varieties were significant (p < 0.05) for all measured parameters. Proximate composition results showed that crude protein and fat contents varied from 21.6–28.9% and 21.1–35.7%, respectively. Fatty acid profiles revealed that the three major fatty acids were linoleic acid (52.79–57.13%) followed by α-linolenic acid (12.62–20.24%), and oleic acid (11.08–17.81%). All essential amino acids were detected in all varieties, with arginine (12.66–17.56 mg/100 g protein) present in abundance, whereas lysine was limiting. Substantial differences were found in the mineral content, and potassium (509.96–1182.65 mg/100 g) and iron (5.06–32.37 mg/100 mg) were the main macro- and microminerals found. All cannabinoids were found in small traces and tetrahydrocannabidiol (THC) was only detected in five varieties. To conclude, the nutritional composition of hempseeds with hull makes them suitable to be added into the diets of humans or animals as a highly beneficial novel ingredient.
- Open Access
Predicting fibre digestibility in Holstein dairy cows fed dry-hay-based rations through machine learning
- Open Access
Physical Characterization of Ten Hemp Varieties to Use as Animal Bedding Material
Hemp (Cannabis sativa L.) hurds, the inner bark of the stem, are a poorly appreciated part of the plant that typically represents waste. The aim of this experiment was to describe the physical characteristics, including moisture (M), water absorption (WA), and ammonia absorption (AA), of 10 hemp varieties (Fibranova, Codimono, USO31, CS, Futura 75, Eletta Campana, Carmaleonte, Felina 32, Santhica, and Ferimon) cultivated in Italy. Samples of hemp hurds were ground to 8 mm obtaining hemp shives. Values of M, WA, and AA were determined following the official procedures. The results showed an average of 7.78%, 251.9%, and 50.0% for M, WA, and AA, respectively. Data of M and WA were similar among varieties, whereas a significant difference was found for the AA, varying from 45.0 to 55.5% for the Fibranova and Ferimon varieties, respectively. In conclusion, hemp shives have good physical characteristics, similar to other commercial bedding materials (i.e., wood shavings) but other parameters and on-farm trials will be required to make a full assessment of hemp.
Open AccessPhysical Characterization of Ten Hemp Varieties to Use as Animal Bedding Material
Hemp (Cannabis sativa L.) hurds, the inner bark of the stem, are a poorly appreciated part of the plant that typically represents waste. The aim of this experiment was to describe the physical characteristics, including moisture (M), water absorption (WA), and ammonia absorption (AA), of 10 hemp varieties (Fibranova, Codimono, USO31, CS, Futura 75, Eletta Campana, Carmaleonte, Felina 32, Santhica, and Ferimon) cultivated in Italy. Samples of hemp hurds were ground to 8 mm obtaining hemp shives. Values of M, WA, and AA were determined following the official procedures. The results showed an average of 7.78%, 251.9%, and 50.0% for M, WA, and AA, respectively. Data of M and WA were similar among varieties, whereas a significant difference was found for the AA, varying from 45.0 to 55.5% for the Fibranova and Ferimon varieties, respectively. In conclusion, hemp shives have good physical characteristics, similar to other commercial bedding materials (i.e., wood shavings) but other parameters and on-farm trials will be required to make a full assessment of hemp.
- Open Access
- 1 January 2023
- Published by Oxford University Press (OUP) in Journal of Animal Science
- Vol. 101
Effects of starch sources varying in particle sizes on ruminal fermentation, nutrient flow, starch digestibility, and lactation performance of dairy cows
Cereal grains are the predominant starch source (SS) for dairy cows; however, starch digestibility varies greatly depending on source, grain processing, and potentially interactions between these factors. The objective was to study the effects of the interactions between SS, and particle sizes (PS) on ruminal fermentation, nutrient flow, starch digestibility, and lactation performance of dairy cows. Four ruminally cannulated multiparous Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Two SS (corn or sorghum) used in this study were either finely or coarsely ground (using a 1- or 4-mm screen sieve). Digesta flow was quantified using the reticular sampling technique, applying the triple-marker method. Data were analyzed using the GLIMMIX procedure of SAS version 9.3 (SAS Institute Inc., Cary, NC, USA). For ruminal pH, data were analysed with time as repeated measure. There were no interactions between SS and PS on production or intake, flow, and digestibility of nutrients. Dry matter intake was greater for the corn diet compared to the sorghum diet (25.15 vs. 21.98 kg/d), which consequently affected nutrient intake, however, PS did not affect intake. Milk yield was not affected by SS; however, it was greater for cows fed fine grains than cows fed coarser grains (25.32 vs. 23.16 kg/d). Milk fat and milk protein were not affected by SS or PS. Interactions (SS × PS) were observed for ruminal pH, reticular pH, and volatile fatty acids (VFA) concentrations but not for ruminal NH3–N concentration. Ruminal and reticular pH were greater for sorghum when coarsely ground and the total VFA concentration was decreased, compared to coarse corn and fine sorghum; however, coarsely grinding corn did not affect ruminal or reticular pH nor VFA concentration. Acetate concentration was lower for corn when finely ground; however, finely grinding sorghum did not affect acetate. Decreasing PS increased ruminal digestibility of starch (87.18% vs. 83.43%), reduced the flow of starch to the reticulum (0.79 vs. 0.96 kg/d) but decreased neutral detergent fiber digestibility in the rumen (30.23% vs. 34.88%). Although SS were differently affected by processing, the effects of PS on production, intake, flow, and digestibility of nutrients were observed regardless of the SS. Furthermore, the effects of decreasing PS on pH and VFA concentrations were more pronounced in sorghum compared to corn. Starch digestibility varies greatly depending on starch source (SS), grain processing, and potentially interactions between these factors. Four ruminally cannulated lactating Holstein cows were fed a total mixed ration that varied in SS and particle sizes (PS) to evaluate the interactions between SS and PS on ruminal fermentation, nutrient flow, starch digestibility, and lactation performance of dairy cows. There were no interactions between SS, and PS on production, intake, flow, and digestibility of nutrients; however, interactions were observed for ruminal pH, reticular pH, volatile fatty acids (VFA) concentrations, and in some VFA molar proportions.
- 1 January 2023
- Published by Oxford University Press (OUP) in Journal of Animal Science
- Vol. 101
Open AccessEffects of starch sources varying in particle sizes on ruminal fermentation, nutrient flow, starch digestibility, and lactation performance of dairy cows
Cereal grains are the predominant starch source (SS) for dairy cows; however, starch digestibility varies greatly depending on source, grain processing, and potentially interactions between these factors. The objective was to study the effects of the interactions between SS, and particle sizes (PS) on ruminal fermentation, nutrient flow, starch digestibility, and lactation performance of dairy cows. Four ruminally cannulated multiparous Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Two SS (corn or sorghum) used in this study were either finely or coarsely ground (using a 1- or 4-mm screen sieve). Digesta flow was quantified using the reticular sampling technique, applying the triple-marker method. Data were analyzed using the GLIMMIX procedure of SAS version 9.3 (SAS Institute Inc., Cary, NC, USA). For ruminal pH, data were analysed with time as repeated measure. There were no interactions between SS and PS on production or intake, flow, and digestibility of nutrients. Dry matter intake was greater for the corn diet compared to the sorghum diet (25.15 vs. 21.98 kg/d), which consequently affected nutrient intake, however, PS did not affect intake. Milk yield was not affected by SS; however, it was greater for cows fed fine grains than cows fed coarser grains (25.32 vs. 23.16 kg/d). Milk fat and milk protein were not affected by SS or PS. Interactions (SS × PS) were observed for ruminal pH, reticular pH, and volatile fatty acids (VFA) concentrations but not for ruminal NH3–N concentration. Ruminal and reticular pH were greater for sorghum when coarsely ground and the total VFA concentration was decreased, compared to coarse corn and fine sorghum; however, coarsely grinding corn did not affect ruminal or reticular pH nor VFA concentration. Acetate concentration was lower for corn when finely ground; however, finely grinding sorghum did not affect acetate. Decreasing PS increased ruminal digestibility of starch (87.18% vs. 83.43%), reduced the flow of starch to the reticulum (0.79 vs. 0.96 kg/d) but decreased neutral detergent fiber digestibility in the rumen (30.23% vs. 34.88%). Although SS were differently affected by processing, the effects of PS on production, intake, flow, and digestibility of nutrients were observed regardless of the SS. Furthermore, the effects of decreasing PS on pH and VFA concentrations were more pronounced in sorghum compared to corn. Starch digestibility varies greatly depending on starch source (SS), grain processing, and potentially interactions between these factors. Four ruminally cannulated lactating Holstein cows were fed a total mixed ration that varied in SS and particle sizes (PS) to evaluate the interactions between SS and PS on ruminal fermentation, nutrient flow, starch digestibility, and lactation performance of dairy cows. There were no interactions between SS, and PS on production, intake, flow, and digestibility of nutrients; however, interactions were observed for ruminal pH, reticular pH, volatile fatty acids (VFA) concentrations, and in some VFA molar proportions.
- Open Access
Economic Feasibility, Benefits and Challenges of On-Farm Artisanal Cheese Making in South Africa
There is limited information regarding artisanal cheese making that can help entrepreneurs evaluate business opportunities and make realistic business decisions. The objective of this study was to assess the economic feasibility, benefits and challenges of on-farm artisanal cheese making. A model was designed to evaluate the economic feasibility of processing hard pecorino-style cheese and soft fresh ricotta on four different smallholder farms. The study assumed a small-scale family-owned business with an average herd size of 10 lactating cows, using 80 L of raw milk a day to make cheese. Projected Cash Flow Statement was used to determine the economic feasibility of cheese making. Sensitivity analysis was conducted using a factor of 10% to determine the changes in net cash flows by varying the milk volume, cheese selling price and both. The positive projected cash flow after the sensitivity analysis for the four farms ranged from $24,073.84 to $33,783.5. The breakeven quantity for the four farms ranged from 325.82 kg to 357.88 kg per year.Overall, the results show that artisanal cheese making is economically viable under the given model assumptions. However, the major challenge noted is that most farmers lack knowledge in terms of the processing techniques, market opportunities and production costs involved in cheese making. Access to this information by small-scale milk producers is vital in considering cheese making as a business.
Open AccessEconomic Feasibility, Benefits and Challenges of On-Farm Artisanal Cheese Making in South Africa
There is limited information regarding artisanal cheese making that can help entrepreneurs evaluate business opportunities and make realistic business decisions. The objective of this study was to assess the economic feasibility, benefits and challenges of on-farm artisanal cheese making. A model was designed to evaluate the economic feasibility of processing hard pecorino-style cheese and soft fresh ricotta on four different smallholder farms. The study assumed a small-scale family-owned business with an average herd size of 10 lactating cows, using 80 L of raw milk a day to make cheese. Projected Cash Flow Statement was used to determine the economic feasibility of cheese making. Sensitivity analysis was conducted using a factor of 10% to determine the changes in net cash flows by varying the milk volume, cheese selling price and both. The positive projected cash flow after the sensitivity analysis for the four farms ranged from $24,073.84 to $33,783.5. The breakeven quantity for the four farms ranged from 325.82 kg to 357.88 kg per year.Overall, the results show that artisanal cheese making is economically viable under the given model assumptions. However, the major challenge noted is that most farmers lack knowledge in terms of the processing techniques, market opportunities and production costs involved in cheese making. Access to this information by small-scale milk producers is vital in considering cheese making as a business.
- Open Access
Effect of Dietary Hemp Cake Inclusion on the In Vivo and Post Mortem Performances of Holstein Veal Calves
Fifty-two male Holstein veal calves were divided into two homogeneous groups receiving two isoenergetic and isonitrogenous concentrates without (CTR group) or with 3% of hemp cake (HC group). The trial lasted for 171 days. All the calves were weighed five times during the trial. At slaughtering, carcasses were weighed and measured. Meat quality was determined on the Longissimus dorsi muscle. Average daily gain in the first period of the experiment (0–80 d) and dressing percentage and rump width of the carcasses were higher in HC group. Cooking weight losses and shear force were higher in the meat of the HC group while color parameters were similar in the two experimental groups. Unexpectedly, the alpha-linolenic acid content of meat was lower in the HC group. In conclusion, hemp cake can be considered an interesting ingredient in the concentrate used for the production of veal calves, but further studies will be needed to determine a suitable dosage in order to improve the nutritional quality of meat (i.e., the n-3 fatty acids content) without negative effects on physical characteristics.
Open AccessEffect of Dietary Hemp Cake Inclusion on the In Vivo and Post Mortem Performances of Holstein Veal Calves
Fifty-two male Holstein veal calves were divided into two homogeneous groups receiving two isoenergetic and isonitrogenous concentrates without (CTR group) or with 3% of hemp cake (HC group). The trial lasted for 171 days. All the calves were weighed five times during the trial. At slaughtering, carcasses were weighed and measured. Meat quality was determined on the Longissimus dorsi muscle. Average daily gain in the first period of the experiment (0–80 d) and dressing percentage and rump width of the carcasses were higher in HC group. Cooking weight losses and shear force were higher in the meat of the HC group while color parameters were similar in the two experimental groups. Unexpectedly, the alpha-linolenic acid content of meat was lower in the HC group. In conclusion, hemp cake can be considered an interesting ingredient in the concentrate used for the production of veal calves, but further studies will be needed to determine a suitable dosage in order to improve the nutritional quality of meat (i.e., the n-3 fatty acids content) without negative effects on physical characteristics.
- Open Access
An Evaluation of Nutritional and Therapeutic Factors Affecting Pre-Weaned Calf Health and Welfare, and Direct-Fed Microbials as a Potential Alternative for Promoting Performance—A Review
The priority for calf rearing has been to maintain good health and welfare in order to promote and sustain future production. However, there have been numerous reports of undesirable levels of morbidity and mortality amongst pre-weaned calves. This may be mitigated or exacerbated by nutritional management practices. Some areas of concern include colostrum feeding, utilization of waste milk, and restrictive milk feeding regimes. Antibiotics may be prescribed at lethal or sub-inhibitory doses to treat or prevent disease. However, extensive antibiotic use may disrupt the gastrointestinal microbiota and aid in expanding the antibiotic resistant gene pool. In an attempt to reduce the use of antibiotics, there is a demand to find alternative performance enhancers. Direct-fed microbials, also known as probiotics, may comply with this role. A DFM consists of live microorganisms that are biologically active and able to confer health benefits onto the host. Lactic acid bacteria have been the most frequently investigated; however, this field of research has expanded to include spore-forming bacteria and live yeast preparations. This review aims to provide a comprehensive evaluation of the nutritional management strategies that may increase a calf’s susceptibility to morbidity and mortality, the efficacy and sustainability of antibiotics as a tool for managing calf health and welfare, and the potential for DFMs as a supportive strategy for promoting calf wellbeing.
Open AccessAn Evaluation of Nutritional and Therapeutic Factors Affecting Pre-Weaned Calf Health and Welfare, and Direct-Fed Microbials as a Potential Alternative for Promoting Performance—A Review
The priority for calf rearing has been to maintain good health and welfare in order to promote and sustain future production. However, there have been numerous reports of undesirable levels of morbidity and mortality amongst pre-weaned calves. This may be mitigated or exacerbated by nutritional management practices. Some areas of concern include colostrum feeding, utilization of waste milk, and restrictive milk feeding regimes. Antibiotics may be prescribed at lethal or sub-inhibitory doses to treat or prevent disease. However, extensive antibiotic use may disrupt the gastrointestinal microbiota and aid in expanding the antibiotic resistant gene pool. In an attempt to reduce the use of antibiotics, there is a demand to find alternative performance enhancers. Direct-fed microbials, also known as probiotics, may comply with this role. A DFM consists of live microorganisms that are biologically active and able to confer health benefits onto the host. Lactic acid bacteria have been the most frequently investigated; however, this field of research has expanded to include spore-forming bacteria and live yeast preparations. This review aims to provide a comprehensive evaluation of the nutritional management strategies that may increase a calf’s susceptibility to morbidity and mortality, the efficacy and sustainability of antibiotics as a tool for managing calf health and welfare, and the potential for DFMs as a supportive strategy for promoting calf wellbeing.
- Open Access
- 14 July 2022
- Published by MDPI AG in Agriculture
- Vol. 12 (7) , 1023
Growth Performance, Carcass Characteristics and Economic Viability of Nguni Cattle Fed Diets Containing Graded Levels of Opuntia ficus-indica
Given the severe droughts caused by global warming, smallholder beef cattle farmers are faced with serious forage and feed scarcity. This becomes worse for resource-poor farmers who cannot afford commercial feeds. It is therefore crucial to assess the use of low-cost alternative feed resources to supplement free-range beef cattle and ensure sustainable livestock production in ways that stimulate free-range beef farmers’ participation in mainstream beef market. In an attempt to improve free-range beef cattle herds and explore the economic viability of utilizing Opuntia ficus-indica (spineless cactus) cladodes as a supplementary feed, we investigated the impact of cactus diets on animal growth performance and carcass characteristics of Nguni cattle heifers. Four dietary treatments were randomly assigned to thirty-two heifers aged 24 months, weighing, on average, 172.20 ± 27.10 kg, with each dietary treatment replicated to eight individually penned heifers for 90 days. The dietary treatments were control diet (pasture-based energy + protein sources), 10% cactus diet, 20% cactus diet and commercial diet (crop-based energy and commercial protein source). The energy concentration of the control diet was 9.35 MJ/Kg DM and the cactus was included on dry matter basis during formulation of compound diets. Thus, cactus was administered in a dry rather than wet form. The animals were confined in feeding pens 24/7 without access to pasture, with feed and water provided ad libitum. The heifers fed commercial and control diets attained significantly (p < 0.05) higher dry matter intake, average daily gains, fat thickness, carcass conformation scores and lower feed conversion ratio than those fed cactus diets. However, the final body weight gains and carcass weights, rib-eye muscle area and meat pH45min and 24h were comparable (p > 0.05) between heifers fed cactus diets and those fed commercial and control diets. The 10 and 20% cactus diets had greater gross margins (p < 0.05) of $17.47 and $18.62, respectively, than the other diets, due largely to reduced total variable costs. The comparability of carcass traits of heifers fed cactus diets and those fed non-cactus diets as well as higher economic returns from cactus inclusion warrants the use of cactus diets, particularly during drought when commercial feed prices rise.
- 14 July 2022
- Published by MDPI AG in Agriculture
- Vol. 12 (7) , 1023
Open AccessGrowth Performance, Carcass Characteristics and Economic Viability of Nguni Cattle Fed Diets Containing Graded Levels of Opuntia ficus-indica
Given the severe droughts caused by global warming, smallholder beef cattle farmers are faced with serious forage and feed scarcity. This becomes worse for resource-poor farmers who cannot afford commercial feeds. It is therefore crucial to assess the use of low-cost alternative feed resources to supplement free-range beef cattle and ensure sustainable livestock production in ways that stimulate free-range beef farmers’ participation in mainstream beef market. In an attempt to improve free-range beef cattle herds and explore the economic viability of utilizing Opuntia ficus-indica (spineless cactus) cladodes as a supplementary feed, we investigated the impact of cactus diets on animal growth performance and carcass characteristics of Nguni cattle heifers. Four dietary treatments were randomly assigned to thirty-two heifers aged 24 months, weighing, on average, 172.20 ± 27.10 kg, with each dietary treatment replicated to eight individually penned heifers for 90 days. The dietary treatments were control diet (pasture-based energy + protein sources), 10% cactus diet, 20% cactus diet and commercial diet (crop-based energy and commercial protein source). The energy concentration of the control diet was 9.35 MJ/Kg DM and the cactus was included on dry matter basis during formulation of compound diets. Thus, cactus was administered in a dry rather than wet form. The animals were confined in feeding pens 24/7 without access to pasture, with feed and water provided ad libitum. The heifers fed commercial and control diets attained significantly (p < 0.05) higher dry matter intake, average daily gains, fat thickness, carcass conformation scores and lower feed conversion ratio than those fed cactus diets. However, the final body weight gains and carcass weights, rib-eye muscle area and meat pH45min and 24h were comparable (p > 0.05) between heifers fed cactus diets and those fed commercial and control diets. The 10 and 20% cactus diets had greater gross margins (p < 0.05) of $17.47 and $18.62, respectively, than the other diets, due largely to reduced total variable costs. The comparability of carcass traits of heifers fed cactus diets and those fed non-cactus diets as well as higher economic returns from cactus inclusion warrants the use of cactus diets, particularly during drought when commercial feed prices rise.
- Open Access
- 1 June 2022
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 105 (6) , 4961-4970
The diurnal patterns of ruminal enzymatic activity and in vitro digestibility of starch, neutral detergent fiber, and protein
The objective of this study was to determine whether diurnal patterns in starch, neutral detergent fiber (NDF) and protein digestibilities and amylolytic, fibrolytic, and proteolytic activities exist in dairy cows. Rumen fluid was collected from 4 ruminally cannulated Holstein dairy cows before the morning feeding and subsequently every 4 h for a 24-h period. Two of the cows were restricted from feed for 8 h overnight, and the other 2 continued to receive their feed ad libitum, to isolate and quantify the effects of changes in feeding behavior at night. After 2 runs the cows were crossed over between night feeding treatments. Rumen fluid was analyzed for enzymatic activity and in vitro starch, NDF, and nitrogen digestibility. Circadian rhythm analyses of enzymatic activity and in vitro digestibility were conducted by fitting the linear form of a cosine function with a 24-h period. Patterns were observed in activity for amylase, lichenase, endoglucanase, and xylanase, with the highest activities observed at the time points subsequent to milking and feed delivery. Protease activity was unaffected by either feeding treatment or possible feeding behavior. When fitted to a cosine function, all the parameters tested followed a daily pattern that was sensitive to the overnight availability of feed, although the parameters responded differently to the feeding treatment. The patterns displayed by in vitro digestibility results of starch, NDF, and nitrogen, across the various fluid collection time points, were highly variable. The time at peak (acrophase) observed in the enzymatic analysis did not correspond to those observed in the in vitro analysis. These results suggest that different interpretations should be given to enzymatic activities and in vitro digestibility values, and the time of rumen fluid collection relative to feeding time should be considered and reported when rumen fluid is used for research or commercial purposes. Maximum digestibility appears in fact to be reached around 4 to 5 h after the main ration delivery for NDF and starch and around ration delivery for protein.
- 1 June 2022
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 105 (6) , 4961-4970
Open AccessThe diurnal patterns of ruminal enzymatic activity and in vitro digestibility of starch, neutral detergent fiber, and protein
The objective of this study was to determine whether diurnal patterns in starch, neutral detergent fiber (NDF) and protein digestibilities and amylolytic, fibrolytic, and proteolytic activities exist in dairy cows. Rumen fluid was collected from 4 ruminally cannulated Holstein dairy cows before the morning feeding and subsequently every 4 h for a 24-h period. Two of the cows were restricted from feed for 8 h overnight, and the other 2 continued to receive their feed ad libitum, to isolate and quantify the effects of changes in feeding behavior at night. After 2 runs the cows were crossed over between night feeding treatments. Rumen fluid was analyzed for enzymatic activity and in vitro starch, NDF, and nitrogen digestibility. Circadian rhythm analyses of enzymatic activity and in vitro digestibility were conducted by fitting the linear form of a cosine function with a 24-h period. Patterns were observed in activity for amylase, lichenase, endoglucanase, and xylanase, with the highest activities observed at the time points subsequent to milking and feed delivery. Protease activity was unaffected by either feeding treatment or possible feeding behavior. When fitted to a cosine function, all the parameters tested followed a daily pattern that was sensitive to the overnight availability of feed, although the parameters responded differently to the feeding treatment. The patterns displayed by in vitro digestibility results of starch, NDF, and nitrogen, across the various fluid collection time points, were highly variable. The time at peak (acrophase) observed in the enzymatic analysis did not correspond to those observed in the in vitro analysis. These results suggest that different interpretations should be given to enzymatic activities and in vitro digestibility values, and the time of rumen fluid collection relative to feeding time should be considered and reported when rumen fluid is used for research or commercial purposes. Maximum digestibility appears in fact to be reached around 4 to 5 h after the main ration delivery for NDF and starch and around ration delivery for protein.