Extrusion of whole cottonseed enhances nutrient utilization, rumen fermentation, and circulating metabolites and amino acid profiles in heat-stressed lactating Holstein cows.
Feeding extruded whole cottonseed may improve milk yield and nutrient utilization in heat-stressed dairy cows, but broader studies are needed to confirm these findings.
Where it sits
this study against the rest of the adipotide (prohibitin-tp01) corpusSummary and findings
This study evaluated the effects of extruded whole cottonseed (EWC) on nutrient utilization and milk production in 32 heat-stressed lactating Holstein cows. Cows fed EWC showed higher dry matter intake and increased milk production with higher protein and lactose concentrations. Rumen fermentation and blood metabolite profiles were also altered in the EWC group.
Abstract
This study aimed to evaluate the effects of feeding extruded whole cottonseed (EWC) on performance, nutrient digestibility, feeding behavior, ruminal fermentation characteristics, metabolic responses, and amino acid profiles in dairy cows under heat stress condition. Thirty-two multiparous cows (104 ± 14.5 days in milk; mean ± SD) were used in a completely randomized design and assigned to two dietary treatments: a control treatment containing raw whole cottonseed (RWC) and a treatment diet containing EWC. Mean temperature-humidity index (THI) during the experiment was 75.9 ± 1.01, representing moderate, sustained heat stress throughout the study period. There was a treatment × time interaction for DMI, with cows fed EWC showed higher DMI from days 8 to 21. Cows fed EWC produced more milk with greater concentrations of protein, lactose, and solids-not-fat, whereas milk fat percentage decreased. The yields of energy-corrected and fat-corrected milk per DMI, feeding and resting behaviors did not differ between groups. Rumen acetate concentration was lower, whereas propionate concentration tended to higher in EWC-fed cows. Apparent total-tract digestibility of DM was greater and CP digestibility tended to be greater in cows fed EWC, whereas NDF digestibility did not differ. Cows fed EWC exhibited higher blood concentrations of cholesterol and albumin, as well as an increased albumin-to-globulin ratio, while showing a tendency for reduced alkaline phosphatase activity compared with those fed RWC. Furthermore, EWC-fed cows had higher plasma concentrations of glycine, trends for higher arginine, and urea-cycle-related amino acids (AA) including citrulline and ornithine, compared with cows receiving RWC. These findings indicate that inclusion of EWC was associated with greater milk yield and improved milk protein and lactose concentrations, coinciding with enhanced nutrient digestibility and altered ruminal fermentation patterns in cows exposed to moderate heat stress.
Background
The study addresses the impact of dietary modifications on nutrient utilization and milk production in dairy cows under heat stress. Previous research has shown that heat stress can negatively affect milk yield and composition. This study is significant as it explores the potential benefits of extruded whole cottonseed (EWC) in mitigating these effects.
Methods
A completely randomized design was used with 32 multiparous Holstein cows, 104 ± 14.5 days in milk, assigned to two dietary treatments: raw whole cottonseed (RWC) and extruded whole cottonseed (EWC). The study was conducted under moderate heat stress conditions with a mean temperature-humidity index of 75.9 ± 1.01. Primary outcomes included dry matter intake (DMI), milk yield, and milk composition.
Results
Cows fed EWC showed a treatment × time interaction for DMI, with higher intake from days 8 to 21. Milk yield and concentrations of protein and lactose were higher in the EWC group, while milk fat percentage decreased. Rumen acetate concentration was lower, and propionate concentration tended to be higher in EWC-fed cows. Blood metabolite profiles showed higher cholesterol and albumin levels in the EWC group.
Interpretation
The findings suggest that EWC may enhance nutrient utilization and milk production in heat-stressed cows. While the study shows statistically significant improvements in milk yield and composition, the clinical significance in terms of overall dairy production efficiency needs further exploration. The study's limitations, such as its small sample size and specific environmental conditions, may affect the generalizability of the results.
Key findings
- 32 multiparous cows, 104 ± 14.5 days in milk, were studied.
- Mean temperature-humidity index was 75.9 ± 1.01.
- EWC-fed cows had higher dry matter intake from days 8 to 21.
- Milk protein and lactose concentrations were higher in EWC-fed cows.
- Rumen acetate concentration was lower in EWC-fed cows.
Limitations
- small n=32
- specific heat stress conditions
- single-site study
- short-term observation period