Three palatability and digestion trials were conducted with six Arabian geldings fed alfalfa (Medicago sativa L.), endophyte-free tall fescue (Festuca arundinacea Schreb.), and Caucasian bluestem (Bothriochloa caucasica (Trin.) C.E. Hubbard) as hay to determine nutritional value of the hays for horses at maintenance in a Latin Square designed experiment. Alfalfa had higher (P < .01) dry matter digestibility, and voluntary intake, compared to grasses. Tall fescue and Caucasian bluestem did not differ in dry matter digestibility and voluntary intake. Feeding alfalfa resulted in higher (P < .05) intake and digestibility of CP and higher (P < .05) apparent absorption of Ca, P, K, and S, compared to the grass hays. Tall fescue was higher (P < .01) in CP concentration and digestibility, total nonstructural carbohydrate concentration, and apparent absorption of Mg and S, compared to Caucasian bluestem. Caucasian bluestem was higher (P < .05) in Zn compared to tall fescue. At the end of the palatability trials, horses fed alfalfa had higher serum concentrations of blood urea nitrogen, vitamin A, and serum P, S, and Cu, compared to horses fed grasses. Serum Zn was higher (P < .05) and Se tended to be higher (P < .06) in horses fed Caucasian bluestem, compared to tall fescue. All forages were below the recommended dietary Cu and P concentration but only Caucasian bluestem resulted in negative apparent P absorption. Caucasian bluestem would meet most nutrient requirements for horses at maintenance. Alfalfa supplied more crude protein, Ca, Mg, and K than was required by horses at maintenance. / Master of Science

Feeding behaviour is controlled by the integration of both perceived cues from the plant and postingestive signals received by the animal. In general practice, dairy cattle are presented with a variety of feedstuffs throughout each day, in addition to changing feedstuffs over time. In the Australian context, the feeds generally include fodder (usually hay) and pasture whilst grazing, as well as various concentrates. For horses that are stabled for prolonged periods, their diet consists of fodder (again usually hay or chaff) and concentrates, in addition to the pasture consumed whilst allowed access to graze. In such situations, where animals are presented with a range of feedstuffs, some of them novel and for discrete periods of time, it is important that they readily accept the feeds when they are first presented to them. For both lactating dairy cows and performance horses, for example, it is important to avoid periods of low intake, as this can have immediate and sometimes longer-term consequences to animal performance. The daily rate of food intake is the single most important factor affecting animal performance and productivity (Illius et al. 2000) and an animal‟s responses to a feedstuff can be considered the ultimate measure of its quality. The animal‟s first response to the presentation of a new feed, which in this particular study was oaten or lucerne hay, is its level of voluntary intake, which depends in part on palatability. Palatability is an integrative term (Provenza 1995); to provide a quantitative measure of the acceptability of a feedstuff, a „preference value’ can be obtained by describing the preference of one hay relative to an alternate hay also on offer. The Australian fodder industry is increasingly adopting more objective measures of hay quality to improve marketing opportunities, especially in the export industry, and to meet the demands and expectations of local and overseas purchasers of hay. Being able to efficiently and reliably predict the preference value of any particular hay would be beneficial to processors, exporters, users (purchasers) of hay, and possibly plant breeders, to make more informed decisions. This thesis describes a comprehensive analysis of the chemical and physical characteristics of a selected number of oaten and lucerne hays and their relationship to the acceptability or „preference value‟ of the hays for lactating Holstein Friesian cows and Thoroughbred horses. The project aimed to (i) quantify preference values for a large number of oaten hays with dairy cows and horses and a similarly large number of lucerne hays with horses only, and (ii) develop predictive equations for animal preferences based on the chemical and physical properties of the hays and the animal‟s short-term rate of consuming the hays. A total of approximately 8,500 preference tests were conducted with 85 oaten hays offered to lactating Holstein Friesian cows and Thoroughbred horses, and 70 lucerne hays offered to Thoroughbred horses. The hays were selected to cover a range of nutritive values. The intake rate and preferences for all the hays were quantified in a series of tests replicated over time and with different animals. Each „trial‟ hay was offered with four „standard‟ hays (in separate tests). A suite of chemical (nutritive value) traits and physical traits were quantified for the hays. An assessment of the „odour profile‟ was also included in the characterisation of the hays. The nutritive, physical and volatile traits were then related to hay preference values in multiple and simple linear regression models and equations generated to predict hay preference values. A prediction of hay preference made directly from the spectra obtained by near infrared reflectance spectroscopy (NIRS) was also developed. Overall, the average preference value of an oaten hay (i.e., that obtained using the comparisons with all four standard hays) could be predicted from a range of nutritive value traits, typically the contents of acid detergent fibre (ADF), hemicellulose, crude protein (CP) and water soluble carbohydrates (WSC) - with a correlation co-efficient of about 79% with cows and 61% for horses. Acid detergent fibre and CP contents tended to have the biggest influence on preference value for both cows and horses, followed by WSC and hemicellulose content. Examination of lucerne hays offered to horses increased the correlation co-efficient to 74%, with ADF, hemicellulose and CP each having a similar magnitude of effect. This means that these traits, with an appropriate weighting for each, could account for up to about three-quarters of the variation in hay preference values for cows and horses. The in vitro digestibility of dry matter (IVD) of oaten and lucerne hay was nearly as accurate in predicting preference values as using the four nutritive value traits of ADF, hemicellulose, CP and WSC, which was anticipated as digestibility is a function of these chemical traits. Hay physical traits could also be used to predict preference values, although not as accurately as the nutritive value traits or IVD. Of the physical traits, shear energy had the largest effect (co-efficient approximately -1.15 compared to an average of -0.35 for the other traits in the equation). The use of NIRS to directly predict preference values was also encouraging, with the best calibration model yielding a correlation co-efficient of 61 to 81%, depending on the hay (oaten or lucerne) and the animal (cows or horses). Of the total 120 volatile compounds isolated from the oaten hays, six had some relationship with cow preferences and there were also six oaten hay volatiles related to horse preferences. Of the oaten hay volatiles significantly related to preference, four were positively related to cow preference whilst two were negatively related to cow preference. Similarly there were four volatiles positively related to horse preference and two consistently negatively related. Of the six oaten hay volatiles found to influence the preferences of dairy cows and horses, four were common to both species. Of the total of 147 volatile compounds isolated from the lucerne hays, 15 had some relationship with horse preference, with nine positively related to horse preference and six negatively related. The data reported here suggest that a predicted preference value for a hay can be generated using commonly measured quality traits, which would improve a buyer‟s confidence of animals responding favourably when first offered the hay. More specifically, for an average preference value, the most reliable prediction equation was based on nutritive value traits: ADF, hemicellulose, crude protein and water soluble carbohydrates solely. Alternatively a combination of nutritive and physical traits can be used to predict preference: in vitro digestibility, crude protein, water soluble carbohydrates and shear energy. The visible and near infrared spectra obtained by NIRS was also a promising method of prediction, and given the speed and affordability of NIRS, this technology could be further refined and used for routine measurement of predicted hay preference values. The volatile compounds shown to influence preference value of the hay should be identified and further research undertaken to investigate novel approaches to manipulate the preference of hays. Caution should be taken when attempting to use these prediction equations on a single specific hay in a single specific situation. The predictions and relationships investigated in this thesis are based on populations of hays and preferences of a group of animals and therefore some care should be taken when applying them to a particular situation with difference circumstances. Other factors that can influence feed preferences include an animal‟s feeding experiences, basal diet and diet history and various environmental factors unaccounted for here. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1349258 / Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2008

Feeding behaviour is controlled by the integration of both perceived cues from the plant and postingestive signals received by the animal. In general practice, dairy cattle are presented with a variety of feedstuffs throughout each day, in addition to changing feedstuffs over time. In the Australian context, the feeds generally include fodder (usually hay) and pasture whilst grazing, as well as various concentrates. For horses that are stabled for prolonged periods, their diet consists of fodder (again usually hay or chaff) and concentrates, in addition to the pasture consumed whilst allowed access to graze. In such situations, where animals are presented with a range of feedstuffs, some of them novel and for discrete periods of time, it is important that they readily accept the feeds when they are first presented to them. For both lactating dairy cows and performance horses, for example, it is important to avoid periods of low intake, as this can have immediate and sometimes longer-term consequences to animal performance. The daily rate of food intake is the single most important factor affecting animal performance and productivity (Illius et al. 2000) and an animal‟s responses to a feedstuff can be considered the ultimate measure of its quality. The animal‟s first response to the presentation of a new feed, which in this particular study was oaten or lucerne hay, is its level of voluntary intake, which depends in part on palatability. Palatability is an integrative term (Provenza 1995); to provide a quantitative measure of the acceptability of a feedstuff, a „preference value’ can be obtained by describing the preference of one hay relative to an alternate hay also on offer. The Australian fodder industry is increasingly adopting more objective measures of hay quality to improve marketing opportunities, especially in the export industry, and to meet the demands and expectations of local and overseas purchasers of hay. Being able to efficiently and reliably predict the preference value of any particular hay would be beneficial to processors, exporters, users (purchasers) of hay, and possibly plant breeders, to make more informed decisions. This thesis describes a comprehensive analysis of the chemical and physical characteristics of a selected number of oaten and lucerne hays and their relationship to the acceptability or „preference value‟ of the hays for lactating Holstein Friesian cows and Thoroughbred horses. The project aimed to (i) quantify preference values for a large number of oaten hays with dairy cows and horses and a similarly large number of lucerne hays with horses only, and (ii) develop predictive equations for animal preferences based on the chemical and physical properties of the hays and the animal‟s short-term rate of consuming the hays. A total of approximately 8,500 preference tests were conducted with 85 oaten hays offered to lactating Holstein Friesian cows and Thoroughbred horses, and 70 lucerne hays offered to Thoroughbred horses. The hays were selected to cover a range of nutritive values. The intake rate and preferences for all the hays were quantified in a series of tests replicated over time and with different animals. Each „trial‟ hay was offered with four „standard‟ hays (in separate tests). A suite of chemical (nutritive value) traits and physical traits were quantified for the hays. An assessment of the „odour profile‟ was also included in the characterisation of the hays. The nutritive, physical and volatile traits were then related to hay preference values in multiple and simple linear regression models and equations generated to predict hay preference values. A prediction of hay preference made directly from the spectra obtained by near infrared reflectance spectroscopy (NIRS) was also developed. Overall, the average preference value of an oaten hay (i.e., that obtained using the comparisons with all four standard hays) could be predicted from a range of nutritive value traits, typically the contents of acid detergent fibre (ADF), hemicellulose, crude protein (CP) and water soluble carbohydrates (WSC) - with a correlation co-efficient of about 79% with cows and 61% for horses. Acid detergent fibre and CP contents tended to have the biggest influence on preference value for both cows and horses, followed by WSC and hemicellulose content. Examination of lucerne hays offered to horses increased the correlation co-efficient to 74%, with ADF, hemicellulose and CP each having a similar magnitude of effect. This means that these traits, with an appropriate weighting for each, could account for up to about three-quarters of the variation in hay preference values for cows and horses. The in vitro digestibility of dry matter (IVD) of oaten and lucerne hay was nearly as accurate in predicting preference values as using the four nutritive value traits of ADF, hemicellulose, CP and WSC, which was anticipated as digestibility is a function of these chemical traits. Hay physical traits could also be used to predict preference values, although not as accurately as the nutritive value traits or IVD. Of the physical traits, shear energy had the largest effect (co-efficient approximately -1.15 compared to an average of -0.35 for the other traits in the equation). The use of NIRS to directly predict preference values was also encouraging, with the best calibration model yielding a correlation co-efficient of 61 to 81%, depending on the hay (oaten or lucerne) and the animal (cows or horses). Of the total 120 volatile compounds isolated from the oaten hays, six had some relationship with cow preferences and there were also six oaten hay volatiles related to horse preferences. Of the oaten hay volatiles significantly related to preference, four were positively related to cow preference whilst two were negatively related to cow preference. Similarly there were four volatiles positively related to horse preference and two consistently negatively related. Of the six oaten hay volatiles found to influence the preferences of dairy cows and horses, four were common to both species. Of the total of 147 volatile compounds isolated from the lucerne hays, 15 had some relationship with horse preference, with nine positively related to horse preference and six negatively related. The data reported here suggest that a predicted preference value for a hay can be generated using commonly measured quality traits, which would improve a buyer‟s confidence of animals responding favourably when first offered the hay. More specifically, for an average preference value, the most reliable prediction equation was based on nutritive value traits: ADF, hemicellulose, crude protein and water soluble carbohydrates solely. Alternatively a combination of nutritive and physical traits can be used to predict preference: in vitro digestibility, crude protein, water soluble carbohydrates and shear energy. The visible and near infrared spectra obtained by NIRS was also a promising method of prediction, and given the speed and affordability of NIRS, this technology could be further refined and used for routine measurement of predicted hay preference values. The volatile compounds shown to influence preference value of the hay should be identified and further research undertaken to investigate novel approaches to manipulate the preference of hays. Caution should be taken when attempting to use these prediction equations on a single specific hay in a single specific situation. The predictions and relationships investigated in this thesis are based on populations of hays and preferences of a group of animals and therefore some care should be taken when applying them to a particular situation with difference circumstances. Other factors that can influence feed preferences include an animal‟s feeding experiences, basal diet and diet history and various environmental factors unaccounted for here. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1349258 / Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2008

Thesis (MSc. (Animal Production)) -- University of Limpopo, 2018 / A study was done to determine the effect of Acacia (A.) karroo, A. tortilis or A. nilotica leaf meal inclusion in a diet on methane emission and productivity of yearling male Boer goats fed a basal diet of Avena sativa hay. The first part of the study was conducted to determine and compare nutrient contents and tannin levels of A. karroo, A. tortilis and A. nilotica leaf meals and Avena sativa hay in a completely randomised design. The diets means were compared using Fisher’s least significant difference at the 5 % level of probability. The three Acacia species had higher (P<0.05) crude protein contents compared to Avena sativa hay, ranging from 12.42 to 14.49 %. No tannins were detected in Avena sativa hay. Among Acacia species, A. nilotica leaves had higher (P<0.05) total phenolic and total tannin contents than A. karroo and A. tortilis leaves, the latter being similar (P>0.05). All three Acacia species had similar (P>0.05) contents of condensed tannins, ranging from 1.49 to 1.76 %. However, only A. nilotica leaves had hydrolysable tannins of 128 mg/g. The second part of the study was conducted to determine the effect of A. karroo, A. tortilis or A. nilotica leaf meal inclusion level on diet intake and digestibility, methane emission, productivity and blood profiles of yearling male Boer goats. A total of three experiments were conducted and different goats were used in each experiment. A grand total of thirty six (twelve per experiment) yearling male Boer goats with initial mean live weights of 23 ± 2 kg (experiment 1), 23 ± 2 kg (experiment 2) and 23 ± 2 kg (experiment 3) were used in 21-day experiments. The goats were randomly assigned to four dietary treatments, each containing A. karroo, A. tortilis or A. nilotica leaf meal inclusion levels at 10, 15, 20 and 30 % with Avena sativa hay as a basal diet. Each goat was housed in well-ventilated individual metabolic pen. The diets were replicated three times. The data collected were subjected to analysis of covariance and analysis of variance in a completely randomized design using SAS. Differences were separated at 5 % level of probability. Additionally, regression equations were used to determine the relationships and responses in optimal diet intake and digestibility, methane emission, productivity and blood profiles of yearling male Boer goats to differing inclusion levels of A. karroo, A. tortilis and A. nilotica leaf meal. v Experiment 1 involved feeding different levels of A. karroo leaf meal inclusion to yearling male Boer goats fed Avena sativa hay as a basal diet. Results of methane emission before and during the experiment indicated that inclusion of A. karroo leaf meal in the diets of goats reduced (P<0.05) methane emission. Similarly, some of the blood parameters before and after experiment were affected (P<0.05) by inclusion of A. karroo leaf meal. However, A. karroo leaf meal inclusion level had no effect (P>0.05) on diet intake, methane emission, live weight changes and digestibility, except (P<0.05) for digestibility of crude fibre. Feed conversion ratio improved linearly with increased A. karroo leaf meal inclusion level. In the case of experiment 2, results of methane emission before and during the experiment indicated that inclusion of A. tortilis leaf meal in the diets of goats reduced (P<0.05) methane emission. Similarly, some of the blood parameters before and after the experiment were affected (P<0.05) by inclusion of A. tortilis leaf meal. However, variation in A. tortilis leaf meal inclusion level had comparable effect (P>0.05) on methane emission, live weight changes and digestibility, except (P<0.05) for digestibility of crude protein and acid detergent fibre. Diet intake and feed conversion ratio were affected (P<0.05) by A. tortilis leaf meal inclusion level. A positive relationship was observed between A. tortilis leaf meal inclusion level and diet intake. In experiment 3, results of methane emission before and during the experiment indicated that inclusion of A. nilotica leaf meal in the diets of goats reduced (P<0.05) methane emission. Similarly, some of the blood parameters before and the after experiment were affected (P<0.05) by inclusion of A. nilotica leaf meal. Apart from diet fat digestibility and feed conversion ratio, no statistical differences (P>0.05) were observed on diet intake, digestibility and live weight changes of goats fed A. nilotica leaf meal inclusion level. Positive relationships were observed between A. nilotica leaf meal inclusion level, diet fat digestibility and feed conversion ratio in male Boer goats. The high crude protein and low tannin contents in A. karroo, A. tortilis and A. nilotica leaves indicate that these Acacia species can be safe to use as a source of protein in animal nutrition if used sparingly. It was noted that nutrient intake, digestibility, vi feed conversion ratio and blood profiles of Boer goats in the present study were optimised at different inclusion levels for all the three Acacia species. This may imply that inclusion levels of A. karroo, A. tortilis and A. nilotica leaf meals for optimal productivity will depend on the Acacia species used and, also, on particular productivity parameters in question. Although, A. karroo, A. tortilis and A. nilotica leaf meal reduced methane emission, optimal reduction in methane emission was not determined. Further validation is required to determine Acacia inclusion levels for optimal methane production and emission by goats. / NRF (National Research Foundation), AGRISETA (Agricultural Sector and Education Training Authority) and NSFAS (National Students Financial Aid Scheme)