Developing a continuous adjustment factor for dry matter intake of gestating and lactating ewes

Intake is a multifactorial process that is influenced by animal type, environmental factors, and diet characteristics. Sheep, especially, have specific eating habits, with a greater selection of ingested feed compared to cattle. Thus, predictive equations for dry matter intake (DMI) must constantly be reviewed. The objective of this study was to combine different adjustment factors to develop one continuous adjustment factor for predicting the DMI of pregnant, dry, and lactating ewes. The equations evaluated for non-lactation ewes accounts for metabolic body weight and weight gain, and the equation for lactating ewes includes milk production and its fat content. The database used in this study was pooled from hair sheep ewes, two to four years old, with controlled feeding, during the pregnancy and lactating physiological phases. For the overall predictions (gestating and lactating ewes), the adjusted DMI prediction had greater accuracy but lower precision than the unadjusted DMI prediction. However, adjusting DMI increased the adequacy of the prediction as the mean square error of prediction difference (ΔMSEP) decreased (p = 0.0328). Similarly, for gestating ewes, the adjusted predicted DMI had a lower ΔMSEP than the unadjusted predicted DMI (p < 0.001). For lactating ewes, no difference was detected between the adjusted and unadjusted predicted DMI based on the ΔMSEP statistics (p = 0.3672), but the assumption that peak milk was 28 days (default) worsened the predictability of the adjusted predicted DMI as it had lower precision and accuracy. Adjustments for predicted DMI of dry and lactating ewes are necessary to increase adequacy and precision.

Developing a continuous adjustment factor for dry matter intake of gestating and lactating ewes

Intake is a multifactorial process that is influenced by animal type, environmental factors, and diet characteristics. Sheep, especially, have specific eating habits, with a greater selection of ingested feed compared to cattle. Thus, predictive equations for dry matter intake (DMI) must constantly be reviewed. The objective of this study was to combine different adjustment factors to develop one continuous adjustment factor for predicting the DMI of pregnant, dry, and lactating ewes. The equations evaluated for non-lactation ewes accounts for metabolic body weight and weight gain, and the equation for lactating ewes includes milk production and its fat content. The database used in this study was pooled from hair sheep ewes, two to four years old, with controlled feeding, during the pregnancy and lactating physiological phases. For the overall predictions (gestating and lactating ewes), the adjusted DMI prediction had greater accuracy but lower precision than the unadjusted DMI prediction. However, adjusting DMI increased the adequacy of the prediction as the mean square error of prediction difference (ΔMSEP) decreased (p = 0.0328). Similarly, for gestating ewes, the adjusted predicted DMI had a lower ΔMSEP than the unadjusted predicted DMI (p < 0.001). For lactating ewes, no difference was detected between the adjusted and unadjusted predicted DMI based on the ΔMSEP statistics (p = 0.3672), but the assumption that peak milk was 28 days (default) worsened the predictability of the adjusted predicted DMI as it had lower precision and accuracy. Adjustments for predicted DMI of dry and lactating ewes are necessary to increase adequacy and precision.(AU)

The geometry of the lactation curve based on Wood's equation: a two-step prediction

Lactation records from cows of the southwestern Paraná state, Brazil, form the dataset of this study. We applied the information-theoretic approach to evaluate the ability of the nonlinear Wood, Brody, Dijkstra, and Gamma functions to fit to these data by employing a two-step technique based on nonlinear mixed-effects models and generalized linear mixed-effects models. Wood's equation was fitted with the combination of a first-order autoregressive correlation structure and a variance function to account for heteroscedasticity. This version was the best choice to mimic lactation records. Some geometric attributes of Wood's model were deduced, mainly the ascending specific rate from parturition to peak milk yield and the descending specific rate as a measure of the lactation persistence of the milk yield at peak production. Breed and parity order of the cows were assumed as fixed effects to obtain a reliable model fitting process. Regardless of breed, first-order parity cows had greater persistency than their older counterparts, and the greater the ascending rate of milk yield from the parturition to the peak, the sharper the decrease in milk yield post-peak; therefore, the rates (absolute values) of ascending and descending phases correlated positively. Nonetheless, the actual estimated values of the descending phase rates are negative. Wood's equation was flexible enough to mimic either concave- and convex-shaped lactation profiles. The correlations between both peak milk yield and random estimates for ß with total milk yield per lactation were positive. However, peak milk yield might not be the only variable used for ranking cows; the total milk yield integrates all information of the lactation profile through the estimated parameters of Wood's equation.(AU)

Do fibrolytic, proteolytic and amylolytic enzymes influence the in vitro fermentation characteristics of forage? / Enzimas fibrolíticas, amilolíticas e proteolíticas influenciam as características de fermentação in vitro de forragem?

The effects of increasing doses of three exogenous enzymes preparations with fibrolytic activity (FIB- 0, 0.6, 1.2, 1.8, and 2.4 mg mL-¹liquid volume incubated), amylolytic activity (AMZ - 0, 0.05, 0.10,0.15, and 0.20 mg mL-¹liquid volume incubated), and proteolytic activity (PRO - 0, 0.05, 0.10, 0.15, and 0.20 mg mL-¹ liquid volume incubated ) on gas production (GP), kinetic parameters, and fermentation profile of Brachiaria brizantha cv. Marandu were evaluated using the in vitro gas production technique. Ruminal liquid was obtained from two rumen-cannulated Santa Inês sheep maintained on pasture. Accumulated gas production was measured during 96 hours of incubation, measured at 18 different time points. The determined parameters were pH, asymptotic gas production (mL g-¹), rate of gas production (h-¹), lag time (h), organic matter digestibility (OMD, g g-¹ DM), metabolizable energy (ME, MJ kg-¹DM), and neutral detergent fiber digestibility (NDFD, mg g-¹ DM). Increasing the FIB dose linearly increased (P < 0.05) the asymptotic gas production. However, the rate of gas production and the lagtime showed linear decreases (P < 0.05). Addition of FIB also linearly increased (P < 0.05) the GP at all incubation times, as well as the OMD, NDFD and ME. Addition of AMZ linearly increased (P <0.05) the asymptotic gas production, but GP linear increased (P < 0.05) only at the 6-hour and 12-hour time points. The rate of gas production and the lag time decreased linearly (P < 0.05) in response to increasing AMZ addition. Inclusion of PRO did not affect (P > 0.05) asymptotic gas production, but there was quadratic effect (P < 0.05) on the rate of gas production, the lag time, and the GP at the 6-hour and 12-hour time points. The OMD, NDFD and ME were not affected by PRO addition. Thus, fibrolytic, amylolytic and proteolytic enzymes are effective in reducing the lag time and increasing thein vitro gas production from Brachiaria Brizantha cv.[...](AU)

Avaliou-se os efeitos de doses crescentes de três enzimas exógenas: fibrolíticas (FIB), 0; 0,6; 1,2; 1,8 e 2,4 mg mL-¹ volume de líquido incubado; amilolíticas (AMZ), 0; 0,05; 0,10; 0,15 e 0,20 mg mL-¹ volume de líquido incubado, proteolíticas (PRO), 0; 0,05; 0,10; 0,15 e 0,20 mg mL-¹ volume de líquido incubado, sobre a produção de gases (PG), parâmetros cinéticos e perfil da fermentação da Brachiaria brizantha cv. Marandu usando a técnica in vitro de produção de gases. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, mantidos em regime de pastejo. A produção de gases acumulada foi obtida durante 96h00 de incubação, mensurada em 18 tempos. Ao final da incubação foram determinados o pH, produção de gás assintótica (mL g-¹), taxa de degradação fracional (h-¹), lag time (h), digestibilidade da matéria orgânica (DMO, g/g MS incubada por 24h00), energia metabolizável (EM, MJ kg-¹ MS) e a digestibilidade da fibra insolúvel em detergente neutro (DFDN, mg g-¹ MS). As doses de FIB aumentaram linearmente (P < 0,05) a produção de gases assintótica. Entretanto, a taxa de degradação fracional e lag time reduziram linearmente (P < 0,05). A adição de FIB também aumentou linearmente (P < 0,05) a PG em todos os tempos de incubação, DMO, DFDN e EM. A inclusão de AMZ aumentou linearmente (P < 0,05) a produção de gases assintótica, e a PG somente nos tempos 6 e 12 horas após a incubação. A taxa de degradação fracional e lag time reduziu linearmente (P < 0,05) com a inclusão de AMZ. A inclusão de PRO não modificou (P > 0,05) a produção de gás assintótica, mas promoveu efeito quadrático (P < 0,05) na taxa de degradação fracional, lag time, e PG nos tempos 6 e 12. No entanto, PRO não afetou DMO, DFDN e EM. As enzimas fibrolíticas, amilolíticas e proteolíticas são efetivas em reduzir o lag time e aumentar a produção de gases in vitro da Brachiaria Brizantha cv.[...](AU)

Exogenous enzyme on in vitro gas production and ruminal fermentation of diet containing high level of concentrate / Enzimas exógenas sobre produção de gás e fermentação ruminal in vitro de dieta contendo alta nível de concentrado

Exogenous enzyme preparations (fibrolytic activity (FIB), 0, 0.6, 1.2, 1.8, and 2.4 mg/ml liquid volume incubated; amylolytic activity (AMZ), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated; proteolytic activity (PRO), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated) were incubated in vitro. Their fermentation effects were assessed based on accumulated gas production, kinetic parameters, and fermentation profile using the technique of gas fermentation. Ruminal liquid was obtained from two rumen cannulated Santa Inês sheep, fed a diet with roughage-to-concentrate ratio of 20:80. Accumulated gas production was during 96 h of incubation, measured at 18 different times. After incubation, pH, dry matter degradability (DMD), organic matter in vitro digestibility (OMD), metabolisable energy (ME), partitioning factor (PF96), gas yield (GY24), short chain fatty acids (SCFA), and microbial protein production (MCP) were evaluated. Increasing FIB dose linearly decreased (P 0.05) lag time without affecting others kinetic parameters. However, FIB increased the accumulated gas production, resulting in improved DMD, OMD, ME, GY24 and SCFA. The addition of AMZ decreased linearly (P 0.05) lag time and increased (P 0.05) gas production on initial times of incubation without altering the fermentation profile. The inclusion of PRO did not affect (P>0.05) the evaluated parameters. The addition of these exogenous enzyme preparations with fibrolytic activity altered ruminal fermentation in vitro of diets containing high levels of concentrates.(AU)

Preparações de enzimas exógenas (atividade fibrolítica (FIB); 0,0; 0,6; 1,2; 1,8 e 2,4 mg/ml do volume de líquido incubado; atividade amilolítica (AMZ); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado; atividade proteolítica (PRO); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado) incubado in vitro. Os efeitos de fermentação foram avaliados com base na produção de gás acumulado, parâmetros cinéticos e, perfil de fermentação usando a técnica de fermentação in vitro. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, alimentados com dieta relação volumoso:concentrado de 20:80. A produção de gás acumulada foi durante 96 h de incubação, mensurados em 18 tempos diferentes. Após a incubação foi avaliado pH, digestibilidade da material seca (DMS), digestibilidade da material orgânica (DMO), energia metabolizável (EM), fator de partição (FP96), rendimento de gás (RG24), ácidos graxos de cadeia curta (AGCC), e produção de proteína microbiana (PPM). O incremento de doses linear de FIB diminuiu (P 0,05) o lag time sem afetar outros parâmetros cinéticos. No entanto, adição de FIB aumentou a produção de gás acumulado, resultando em incremento na DMS, DMO, EM, RG24 e AGCC. A adição de AMZ diminuiu linearmente (P 0,05) lag time e incrementou (P 0,05) produção de gás nos tempos iniciais de incubação sem alterar o perfil de fermentação. A inclusão de PRO não afetou (P>0,05) os parâmetros avaliados. As adições de preparações enzimáticas exógenas com atividades fibrolíticas alteram fermentação ruminal in vitro de dieta de alta níveis de concentrado.(AU)

Exogenous enzyme on in vitro gas production and ruminal fermentation of diet containing high level of concentrate / Enzimas exógenas sobre produção de gás e fermentação ruminal in vitro de dieta contendo alta nível de concentrado

Exogenous enzyme preparations (fibrolytic activity (FIB), 0, 0.6, 1.2, 1.8, and 2.4 mg/ml liquid volume incubated; amylolytic activity (AMZ), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated; proteolytic activity (PRO), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated) were incubated in vitro. Their fermentation effects were assessed based on accumulated gas production, kinetic parameters, and fermentation profile using the technique of gas fermentation. Ruminal liquid was obtained from two rumen cannulated Santa Inês sheep, fed a diet with roughage-to-concentrate ratio of 20:80. Accumulated gas production was during 96 h of incubation, measured at 18 different times. After incubation, pH, dry matter degradability (DMD), organic matter in vitro digestibility (OMD), metabolisable energy (ME), partitioning factor (PF96), gas yield (GY24), short chain fatty acids (SCFA), and microbial protein production (MCP) were evaluated. Increasing FIB dose linearly decreased (P 0.05) lag time without affecting others kinetic parameters. However, FIB increased the accumulated gas production, resulting in improved DMD, OMD, ME, GY24 and SCFA. The addition of AMZ decreased linearly (P 0.05) lag time and increased (P 0.05) gas production on initial times of incubation without altering the fermentation profile. The inclusion of PRO did not affect (P>0.05) the evaluated parameters. The addition of these exogenous enzyme preparations with fibrolytic activity altered ruminal fermentation in vitro of diets containing high levels of concentrates.

Preparações de enzimas exógenas (atividade fibrolítica (FIB); 0,0; 0,6; 1,2; 1,8 e 2,4 mg/ml do volume de líquido incubado; atividade amilolítica (AMZ); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado; atividade proteolítica (PRO); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado) incubado in vitro. Os efeitos de fermentação foram avaliados com base na produção de gás acumulado, parâmetros cinéticos e, perfil de fermentação usando a técnica de fermentação in vitro. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, alimentados com dieta relação volumoso:concentrado de 20:80. A produção de gás acumulada foi durante 96 h de incubação, mensurados em 18 tempos diferentes. Após a incubação foi avaliado pH, digestibilidade da material seca (DMS), digestibilidade da material orgânica (DMO), energia metabolizável (EM), fator de partição (FP96), rendimento de gás (RG24), ácidos graxos de cadeia curta (AGCC), e produção de proteína microbiana (PPM). O incremento de doses linear de FIB diminuiu (P 0,05) o lag time sem afetar outros parâmetros cinéticos. No entanto, adição de FIB aumentou a produção de gás acumulado, resultando em incremento na DMS, DMO, EM, RG24 e AGCC. A adição de AMZ diminuiu linearmente (P 0,05) lag time e incrementou (P 0,05) produção de gás nos tempos iniciais de incubação sem alterar o perfil de fermentação. A inclusão de PRO não afetou (P>0,05) os parâmetros avaliados. As adições de preparações enzimáticas exógenas com atividades fibrolíticas alteram fermentação ruminal in vitro de dieta de alta níveis de concentrado.

Do fibrolytic, proteolytic and amylolytic enzymes influence the in vitro fermentation characteristics of forage? / Enzimas fibrolíticas, amilolíticas e proteolíticas influenciam as características de fermentação in vitro de forragem?

The effects of increasing doses of three exogenous enzymes preparations with fibrolytic activity (FIB- 0, 0.6, 1.2, 1.8, and 2.4 mg mL-¹liquid volume incubated), amylolytic activity (AMZ - 0, 0.05, 0.10,0.15, and 0.20 mg mL-¹liquid volume incubated), and proteolytic activity (PRO - 0, 0.05, 0.10, 0.15, and 0.20 mg mL-¹ liquid volume incubated ) on gas production (GP), kinetic parameters, and fermentation profile of Brachiaria brizantha cv. Marandu were evaluated using the in vitro gas production technique. Ruminal liquid was obtained from two rumen-cannulated Santa Inês sheep maintained on pasture. Accumulated gas production was measured during 96 hours of incubation, measured at 18 different time points. The determined parameters were pH, asymptotic gas production (mL g-¹), rate of gas production (h-¹), lag time (h), organic matter digestibility (OMD, g g-¹ DM), metabolizable energy (ME, MJ kg-¹DM), and neutral detergent fiber digestibility (NDFD, mg g-¹ DM). Increasing the FIB dose linearly increased (P 0.05) asymptotic gas production, but there was quadratic effect (P < 0.05) on the rate of gas production, the lag time, and the GP at the 6-hour and 12-hour time points. The OMD, NDFD and ME were not affected by PRO addition. Thus, fibrolytic, amylolytic and proteolytic enzymes are effective in reducing the lag time and increasing thein vitro gas production from Brachiaria Brizantha cv.[...]

Avaliou-se os efeitos de doses crescentes de três enzimas exógenas: fibrolíticas (FIB), 0; 0,6; 1,2; 1,8 e 2,4 mg mL-¹ volume de líquido incubado; amilolíticas (AMZ), 0; 0,05; 0,10; 0,15 e 0,20 mg mL-¹ volume de líquido incubado, proteolíticas (PRO), 0; 0,05; 0,10; 0,15 e 0,20 mg mL-¹ volume de líquido incubado, sobre a produção de gases (PG), parâmetros cinéticos e perfil da fermentação da Brachiaria brizantha cv. Marandu usando a técnica in vitro de produção de gases. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, mantidos em regime de pastejo. A produção de gases acumulada foi obtida durante 96h00 de incubação, mensurada em 18 tempos. Ao final da incubação foram determinados o pH, produção de gás assintótica (mL g-¹), taxa de degradação fracional (h-¹), lag time (h), digestibilidade da matéria orgânica (DMO, g/g MS incubada por 24h00), energia metabolizável (EM, MJ kg-¹ MS) e a digestibilidade da fibra insolúvel em detergente neutro (DFDN, mg g-¹ MS). As doses de FIB aumentaram linearmente (P 0,05) a produção de gás assintótica, mas promoveu efeito quadrático (P < 0,05) na taxa de degradação fracional, lag time, e PG nos tempos 6 e 12. No entanto, PRO não afetou DMO, DFDN e EM. As enzimas fibrolíticas, amilolíticas e proteolíticas são efetivas em reduzir o lag time e aumentar a produção de gases in vitro da Brachiaria Brizantha cv.[...]