Calan gate (CG) facility and on the grassland calculated by the alkane method 39 5.1: Average composition (g/kg OM) of kikuyu samples during dry matter digestibility. Friesland (FB) bulls during the dry matter digestibility study 43 5.3: Average composition (g/kg OM) of faecal samples and average nutrient digestibility. g/kg) for Hereford (HB) and Friesland (FB) bulls during dry matter digestibility.
AOF AOG
UOP W 0.75
Introduction
- Kikuyu - an important summer pasture for animal production in KwaZulu-Natal
- Breed history and maturity types
- Previous research done by Horne (1996) and Fushai (1997)
- Project objective
- Thesis outline
- Introduction
- Characteristics of kikuyu
- Introduction of kikuyu to South Africa
- Morphology of kikuyu
- Ideal growth conditions for kikuyu
- Nutrient requirements of growing cattle
- Nutritive value of kikuyu
- Protein content
- Carbohydrate content
- Mineral content
- Factors affecting the intake and digestibility of kikuyu
- Methods to determine kikuyu intake and digestibility estimates
- Digesta retention time and faecal marker excretion patterns
- Plant attributes affecting kikuyu intake
- The relationship between grazing behaviour and forage intake
- Introduction
- Materials and methods .1 Experimental design
- Experimental measures
- Animal health
- Pasture management
- Statistical methods
- Results and discussion
- Age of trial animals
- Weight gain
- Height gain
Growth performance of experimental bulls is detailed in Chapter 3. Intake measured by electronic feed gates and alkane estimation are compared and presented in Chapter 4. Evaluation of kikuyu digestibility by metabolic crates is discussed in Chapter 5. Passage of insoluble markers through the digestive tract is detailed in Chapter 6. The Friesland run data were excluded from the growth analysis investigation due to the significant age difference (118 days) and since growth was slowed by various diseases (see section 3.2. 3), the leaders were contracted.
1--- HBA·· FB I
Condition score gain
Table 3.4 summarizes the condition scores of the Hereford and Fryslân bulls during the test.
Summary
Introduction
Materials and methods .1 Experimental design
- Experimental measures
- Experimental techniques
- Statistical methods
To alleviate this problem the grass was cut before it was fed to the animals. All grass samples were oven dried (60 °C) until a constant weight was reached and then ground with a 0.5 mm screen. The Mayes method was modified so that the marker was administered to the animal in the form of a suspension instead of a compressed pellet.
After samples of grass and feces were collected, dried in an oven (at 60 °C) and ground (using a 0.5 mm sieve), the alkanes were extracted according to the following procedure (Maraiset al., 1996 and personal communication with Marais, 1997). ):. i). The dried extract was dissolved in 2 ml of petroleum ether (boiling point 60-80°C) and applied. Extracted alkanes were dissolved in hexane (0.7 ml) and 1 µl of this solution was applied to a gas chromatogram column (megabore, 25 m, 100% methyl polysiloxane, 32 microns, carrier gas was nitrogen). The initial injector temperature was 300°C. 'C and the initial detector temperature was 320 °C).
Coated herb samples were extracted using the same procedure as described above, except that 0.5 g of sample and 0.05 g of hexatriacontane (C36) were first added to the 50 ml glass-stoppered tube and instead of all petroleum ether supernatant as in step (iv), an amount of 0.3 ml was immediately applied to the silica column.
Results and discussion
- Initial weight
- Kikuyu composition
- Maximum and minimum temperatures
A comparison of the average intake estimated by the Calan gate method and the alkane method is shown in Table 4.2. A comparison of the average intake estimated by the Calan gate method comparing faecal samples collected in the morning (6h00) and in the afternoon (18h00) is presented in Table 4.3. Although the estimation of alkane intake (when morning and afternoon readings were combined) was not significantly different from the Calan gate method (as presented in Table 4.2), significant trends were found when analyzing time.
A comparison of the average intake of Hereford bulls at the Calan gate facility and at pasture is shown in Table 4.5. The data presented in Table 4.6 show that there is a significant difference of 6% in the dry matter digestibility of kikuyu between the two breeds in the Calan gate investigation. The data presented in Table 4.7 show that there was no significant difference (P=0.086) in the estimated dry matter digestibility of Hereford bulls at the Calan gate facility and on pasture.
There was no relationship between temperature and kikuyu intake for animals at the Calan gate facility.
Summary
Estimates of orial digestibility calculated using the alkane method for comparing Calan gate intake and pasture intake for Hereford bulls are shown in Table 4.7. The mean minimum temperature during the intake investigation at the Calan Gate facility was 15.3 'C while the maximum temperature was 30.1 'C. As the Friesland steers could not be included in the intake investigation, there were not enough animals to compare the two breeds at the Calan gate facility and those at pasture.
There was no significant difference between the intake (mean intake was 102 g OM/kg W o75/day) of Hereford bulls at the Calan gate facility and bulls on pasture, although the chemical composition of the pasture was significantly different from the grass-fed bulls. in the Calan gate facility. The alkane method was used to measure the apparent dry matter digestibility score of Hereford and Friesland bulls while confined in the Calan gate facility. Dry matter digestibility scores of Friesland bulls were 6% lower (P <0.05) than Hereford bulls.
Digestibility of orial matter using alkanes was also compared between that of Hereford bulls at the Calan gate facility and those at pasture.
Introduction
Materials and methods .1 Experimental design
- Experimental measures
- Statistical methods
Results and Discussion
- Kikuyu composition
- Dry matter digestibility estimates
- Nutrient digestibility and faeces composition
- Maximum temperatures
The average composition of the kikuyu grass samples taken daily during the dry matter digestibility study is shown in Table 5.1. The breeds' average intake, faeces and dry matter digestibility estimates are shown in Table 5.2. Table 5.2: Intake, faecal production and dry matter digestibility estimates for Hereford (HB) and Friesland (FB) bulls during the dry matter digestibility study.
There was no significant difference in dry matter digestibility scores for Friesland and Hereford bulls as shown in Table 5.2. The average composition of faecal samples and the digestibility of nutrients taken during the dry matter digestibility test are shown in Table 5.3. The average maximum temperature recorded during the dry matter digestibility test in the digester facility was 26.5 °C.
There was no significant difference between Hereford and Friesland bulls in the dry matter digestibility of kikuyu.
Introduction
Materials and methods .1 Experimental design
- Experimental measures
- Experimental techniques
- Statistical methods
The statistical program Genstat 5 (Release 3.1) (Lawes Agricultural Trust, Rothamsted Experimental Station) was used for statistical analyses. Statistical differences between treatment means were determined by analysis of variance tables using the Students t test at the 5% level.
Results and Discussion
- Faecal marker patterns explained by Grovum and Williams (1973) model
- Faecal marker patterns explained by Genstat QDQ curve
- Faecal marker patterns explained by Genstat gompertz curve
The first appearance of the marker in the faeces (TT) (mean is 10 hours), the mean retention time (MRT) (mean is 44.6 hours) and the rate of faeces produced (mean is 91 g OM/hour) were not not significantly different between the Hereford and Friesland bulls. The rate of faeces produced (F) compared favorably with the results obtained in the metabolic crate study: 2.15 kg OM from the Grovum and Williams model versus 2.2 kg OM measured in the metabolic crate study for the Hereford bulls. Similarly, the Grovum and Williams model calculated 2.22 kg OM compared to 2.4 kg OM of faecal material measured in the metabolic crate study for the Friesland bulls.
Although the alkane marker peaked earlier and at a higher concentration for the Hereford bulls than for the Friesland bulls (shown in Figure 6.1), the variance analysis of the coefficients of Grovum and Williams model (Table 6.1) that digesta flow and mean retention times were not significantly different between the breeds. The analysis of variance data indicated that there was no significant difference in the peak time of digestion (as shown in Table 6.3). However, this is not true as in Table 5.3 (Section 5.3.3) the Friesland bulls extracted more NDF and ADF fractions from the grass (although this trend is not significantly different).
The fact that only the linear variables were significantly different implied that the total concentration of the marker was lower over time in the Friesian bulls.
Summary
This supported the hypothesis that the Friesland bulls could have had a larger intestinal volume in which the marker would be distributed. Intestinal volume would have to be measured to fully quantify the relationship of digesta flow. The gompertz curve analysis (alkane and chromium) only indicated that the linear parameters were significantly different Le.
Introduction
Materials and methods .1 Experimental design
- Experimental measures
- Climatic conditions
- Statistical methods
Results and discussion
- Kikuyu composition
- Activity analysis
Statistical differences between treatment means were determined from analysis of variance tables using Student's Hest at the 5% level. The analysis of variance data summarized in Table 7.3 indicates that there was no significant difference between the behavior of the Hereford bulls and the Friesland bulls and steers. Upon further analysis, when an analysis of variance was performed on pooled values of both behavioral studies, no significant differences were found.
The longer time the animals spent ruminating during study 1 was possibly due to the higher levels of neutral detergent and acidic detergent fibers, which cause greater chewing activity. Finding no significant difference between grazing (or other activities) for Hereford and Friesland bulls confirmed the result of Chapter 4, where there was no significant difference in the intake of Hereford and Friesland bulls while consuming kikuyu pasture . Figure 7.1 shows the average grazing time (minutes per hour) of the varieties per behavioral study.
The graphs support the trend in Table 7.3, that there was no difference in the grazing frequency of the Hereford and Friesland bulls.
Summary
Introduction
Materials and methods .1 Experimental design
- Experimental measures
- Statistical methods
Results and discussion
Table 8.1: Carcass and internal organ weights (kg) and proportions of Hereford (HB) and Fryslân (FB) bulls. The analysis of variance summarized in Table 8.1 indicates that the Friesian bulls had significantly heavier carcasses than the Hereford bulls. This was expected and confirms the results from section 3.3.2, where the Friesian bulls were significantly heavier at the beginning and end of the growing period, although the average daily gain was not significantly different from that of the Hereford bulls.
Likewise, there was no significant difference (except for the liver) in the organ masses or the ratios of organ mass/warm mass between the Hereford and Friesland bulls. The weight of the Friesland bulls' heart, liver, lungs and spleen were all slightly greater, although the difference was not statistically significant, than that of the Hereford bulls presumably because the Friesland were larger animals.
Summary
Conclusions
The alkane method was used to measure apparent dry matter digestibility estimates (presented in Chapter 4) of Hereford and Friesland bulls while they were confined in the Calan gate facility. There was no significant difference between Hereford and Friesland bulls in kikuyu dry matter digestibility (presented in Chapter 5). There was no significant difference between Hereford and Friesland bulls in the amount of faeces produced (mean faeces produced per animal per day was 2.3 kg OM) or nutrient digestibility estimates, although Friesland bulls produced more concentrated faeces (25 % dry) than Hereford bulls in the dry matter digestibility investigation.
The Grovum and Williams model indicated that there was no significant difference in digestive flow through the digestive tract for the Hereford and Friesland bulls for either the alkane or chromium markers. A debatable question is whether the Friesian bulls could have a greater rumen capacity in relation to their size (live weigh frame size) than the Hereford bulls. No significant difference was found between the time at which the Hereford and Friesland bulls performed each activity.
When organ mass was divided by metabolic mass, there was no significant difference between Hereford and Friesland bulls.
Recommendations
Dry matter digestibility estimates (g/kg OM) of grazing animals calculated by the alkane method .. Table 8.15: Daily minimum and maximum ambient temperatures rC) in the Calan gate facility.
![Figure 3.4: Linear regression model (equation [3.1] and [3.2]) of weight (kg) for Hereford (HB) and Friesland (FB) bulls over time (r 2 = 0.6).](https://thumb-ap.123doks.com/thumbv2/pubpdfnet/10639027.0/39.838.101.749.502.999/figure-linear-regression-model-equation-weight-hereford-friesland.webp)
![Figure 3.6: Linear regression model (equation [3.3] and [3.4]) of height (cm) for Hereford (HB) and Friesland (FB) bulls over time (r 2 = 0.54).](https://thumb-ap.123doks.com/thumbv2/pubpdfnet/10639027.0/41.846.125.756.420.918/figure-linear-regression-model-equation-height-hereford-friesland.webp)
