To evaluate the effects of heat stress (HS) environmental conditions and dietary organic acid and pure botanical (OA/PB) supplementation on lactation performance, we enrolled 48 Holstein cows (208 ± 4.65 d in milk [mean ± SD], 3.0 ± 0.42 lactations, 122 ± 4.92 d pregnant) in a study with a completely randomized design. Following a 7-d acclimation in thermoneutral conditions (temperature-humidity index [THI] 68), cows were assigned to 1 of 4 groups (n = 12/group): thermoneutral conditions (TN-Con), HS conditions (HS-Con; diurnal THI 74 to 82), thermoneutral conditions pair-fed to match HS-Con (TN-PF), or HS fed OA/PB (HS-OAPB; 75 mg/kg of body weight; 25% citric acid, 16.7% sorbic acid, 1.7% thymol, 1.0% vanillin, and 55.6% triglyceride; AviPlusR, Vetagro, Italy) for 14 d. Cows were fed a corn silage based total mixed ration top-dressed without (triglyceride only) or with OA/PB. Cows were milked twice daily. Blood was collected on d −1, 1, 2, 3, 7, and 14 for plasma urea N (PUN) quantification. Data were analyzed using a mixed model including fixed effects of treatment, time, and their interaction. Planned contrasts included HS-Con versus (vs.) TN-Con, HS-Con vs. TN-PF, and HS-Con vs. HS-OAPB. Rectal and skin temperatures, and respiration rates were greater in HS-Con and HS-OAPB, relative to TN-Con and TN-PF (P < 0.01). HS-Con had greater water intake, and lower yields of milk and milk lactose and protein, relative to TN-PF (P < 0.01). Yields of energy-corrected milk (ECM) were lower in HS-Con, relative to TN-PF (P < 0.01). HS-OAPB had greater water intakes (P = 0.05) and tendency for greater dry matter intakes, relative to HS-Con (P = 0.14). HS-OAPB had greater ECM yields, relative to HS-Con (P = 0.05). This was due to greater milk protein yields (P = 0.05) and tendency for greater milk yields (P = 0.12) in HS-OAPB, relative to HS-Con. Milk urea N and PUN concentrations were lower in HS-OAPB cows, relative to HS-Con (P < 0.01), which suggests improved N efficiency. We conclude that dietary OA/PB supplementation partially restores lactation performance in heat-stressed dairy cows.
Effects of heat stress conditions and dietary organic acid and pure botanical supplementation on milk production in Holstein cows / A. B. P. Fontoura, A. Javaid, V. Sáinz de la Maza Escolà, M. G. Vogellus, I. R. Frost, R. M. Martinez, N. S. Salandy, S. L. Fubini, E. Grilli, and J. W. McFadden. - ELETTRONICO. - (2022), pp. 1435.172-1435.172. (Intervento presentato al convegno American Dairy Science Association Annual Meeting 2022 tenutosi a Kansas City, MO nel June 19-22, 2022).
Effects of heat stress conditions and dietary organic acid and pure botanical supplementation on milk production in Holstein cows.
V. Sáinz de la Maza Escolà;E. GrilliPenultimo
;
2022
Abstract
To evaluate the effects of heat stress (HS) environmental conditions and dietary organic acid and pure botanical (OA/PB) supplementation on lactation performance, we enrolled 48 Holstein cows (208 ± 4.65 d in milk [mean ± SD], 3.0 ± 0.42 lactations, 122 ± 4.92 d pregnant) in a study with a completely randomized design. Following a 7-d acclimation in thermoneutral conditions (temperature-humidity index [THI] 68), cows were assigned to 1 of 4 groups (n = 12/group): thermoneutral conditions (TN-Con), HS conditions (HS-Con; diurnal THI 74 to 82), thermoneutral conditions pair-fed to match HS-Con (TN-PF), or HS fed OA/PB (HS-OAPB; 75 mg/kg of body weight; 25% citric acid, 16.7% sorbic acid, 1.7% thymol, 1.0% vanillin, and 55.6% triglyceride; AviPlusR, Vetagro, Italy) for 14 d. Cows were fed a corn silage based total mixed ration top-dressed without (triglyceride only) or with OA/PB. Cows were milked twice daily. Blood was collected on d −1, 1, 2, 3, 7, and 14 for plasma urea N (PUN) quantification. Data were analyzed using a mixed model including fixed effects of treatment, time, and their interaction. Planned contrasts included HS-Con versus (vs.) TN-Con, HS-Con vs. TN-PF, and HS-Con vs. HS-OAPB. Rectal and skin temperatures, and respiration rates were greater in HS-Con and HS-OAPB, relative to TN-Con and TN-PF (P < 0.01). HS-Con had greater water intake, and lower yields of milk and milk lactose and protein, relative to TN-PF (P < 0.01). Yields of energy-corrected milk (ECM) were lower in HS-Con, relative to TN-PF (P < 0.01). HS-OAPB had greater water intakes (P = 0.05) and tendency for greater dry matter intakes, relative to HS-Con (P = 0.14). HS-OAPB had greater ECM yields, relative to HS-Con (P = 0.05). This was due to greater milk protein yields (P = 0.05) and tendency for greater milk yields (P = 0.12) in HS-OAPB, relative to HS-Con. Milk urea N and PUN concentrations were lower in HS-OAPB cows, relative to HS-Con (P < 0.01), which suggests improved N efficiency. We conclude that dietary OA/PB supplementation partially restores lactation performance in heat-stressed dairy cows.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
