Empty body (EB) weight (EBW) is used to estimate the energy and protein requirements for maintenance for dairy cattle. It is predicted from live weight (LW), but the prediction can be influenced by a number of factors, e.g., feed and water intake, pregnancy and body condition. The objective of the present study was to develop prediction equations for EBW and carcass weight in lactating dairy cows using LW and other live animal data.

Heat production of animals is mainly derived from body protein metabolism and energy expenditure per unit protein in internal organs is much higher than skeletal muscle. The accurate estimation of CP mass in internal organs can thus improve rationing systems for farm animals. The objective of the present study was to examine relationships between CP mass in internal organs and empty body weight (EBW) with other live animal variables in lactating dairy cows.

As concerns for environmental damage instigated by agricultural processes increase, there is a greater need to develop more ecologically acceptable methods of producing agricultural products. Therefore, in beef production we have to minimise N excretion and maximise N retained. Urea recycling provides a mechanism by which N may be salvaged into bacterial matter that may be digested by the animal to supply amino acids for production purposes. According to Huntington and Archibeque (2000), the amount of recycled urea-N can be influenced by the ruminal ammonia concentration, the OM digestibility and the plasma concentration of urea. The objective of the present study was to examine the effect of different levels of ruminal degradable N (RDN) on nutrient digestion and N metabolism in double-muscled Belgian Blue (dm-BB) bulls fed maize silage based diet.

Following commercial practice in France, there is increased interest in using specifically selected purebred maternal lines as suckler cow dams in the UK. Consequently, there is also a need to evaluate the finishing performance of the concomitant purebred male progeny from these maternal lines within typical UK suckled calf finishing systems. The objective of this study was to compare the post-weaning performance of purebred Charolais (CH) steers and crossbred Limousin x Aberdeen Angus (LIMxAA) steers when finished using a cereal-based ration.

In a previous study, Valkeners et al. (2004) reported that feeding a concentrate-based diet with an imbalance between energy and N release in the rumen did not greatly influence the N balance of double-muscled Belgian Blue (dm-BB) bulls if daily ruminal degradable N (RDN) and fermentable OM (FOM) ratio did not exceed 6.2 g RDN/kg FOM. The objective of the present study was to examine the effects of a higher level of imbalance between energy and N release in the rumen on microbial protein synthesis and N metabolism in dm-BB bulls fed maize silage based diet.

It is now established that the process of milk production and its constituents are affected by different physiological factors, including hormones and neurotransmitters. Bombesin (BBS) is a tetradecapeptide that isolated and characterized from the skin of amphibian frog bombina bombina (Jontown et al., 1995). Subsequently, several BBS-like peptides have been identified in mammals consisting of various forms of gastrin-releasing peptide (GRP) and neuromedin B (NMB), together with their distinct receptor subtypes (Jian et al., 1999). Nowadays, they have been found at different parts of the body such as neuron system, gastrointestinal tract and some nucleuoses of hyphothalamus of vertebrates and invertebrates. The bombesin family of peptides are biologically active in the central nervous system and periphery. Bombesin achieves to its functions by starting the secondary messenger of inositol triphosphate (IP3). The effects of bombsin on production and constituents of the milk are not studied yet. The aim of this experiment was to determine whether injections of bombesin increase milk amount and constituents in the cows.

Recent reports from the United States propose new nutritional guidelines for calves (VanAmburgh 2003). They suggest an accelerated growth programme where calves are offered a high protein milk replacer (CMR) at a level sufficient to achieve a liveweight gain of 1000 g/d up to 8 weeks of age. This is in contrast to many European feeding programmes where calves are offered 25 kg of CMR over 42 days with an expected liveweight gain of 500 to 600 g/day. The objective of this experiment was to evaluate the accelerated growth system under Irish conditions.

Artificial rearing is a common practice for rearing calves from the dairy herd, either for replacement heifers or for beef production. The period from birth to weaning is a critical period for the calf and nutrition is one of the components important to ensure successful rearing of calves. Improved nutrition that allows earlier weaning through a rapid calf growth has the potential to decrease costs. Moreover, it has been shown that healthy, vigorous and well-grown weanling heifers may enter the milking herd sooner (Davis and Drackley, 1998). The objective of this study was to examine the effect of feeding two concentrations of a high protein milk replacer on the health and growth performance of dairy calves until weaning.

High-yielding dairy cows must produce large amounts of milk of a desired quality from a cost-effective diet in order for the farmer to remain in profit. Optimal rumen function and health is a key part of the process of converting nutrients into milk efficiently. Essential oils are steam-volatile or organic-solvent extracts of plants that have been shown to have beneficial effects on human digestion. They are mainly cyclic hydrocarbons and their alcohol, aldehyde or ester derivatives (Wallace, 2004). ‘Crina Ruminants’ is a blend of such essential oil compounds, designed to stimulate rumen activity and boost the population of beneficial microbes, through anti-microbial and digestive stimulant activity. In particular, it is believed to encourage an increase in fibre-fermenting bacteria and to counteract the acidotic rumen conditions that can be caused by feeding high starch diets. The aim of this experiment was to evaluate the effects of ‘Crina Ruminants’ on intake and milk production.

The efficiency of dietary N by dairy cows is generally low, and in part, may be related to an impaired utilization of N in the rumen. A major determinant of microbial protein synthesis is the availability of energy-yielding substrates (Castillo et al., 2001). It seems likely that low ratios of effective rumen degradable protein (ERDP) to fermentable metabolisable energy (FME) will restrict microbial protein synthesis and dry matter intake and, consequently, lead to reduced milk yield (Cabrita et al., 2003). Nitrogen excretion in faeces and urine accounts for a high proportion of N intake, which may be more than 70% of the daily N consumption. Environmental pollution from N as ammonia and nitrates is regarded as a major potential problem world wide. Nutritional manipulations might be a way of significantly increasing N utilization and decreasing N pollution by dairy cows, and where as protein sources are expensive so, the cost of diet decrease (Castillo et al., 2001). The objective of this study was to examine the product and component of milk of dairy cows offered diets with different ratios of ERDP/FME.

Shortage of feed is the main constraint in livestock industry in Iran. High feed cost encourages the farmers to look for cheaper feeds or somehow reduce the feed conversion ratio in the farms. One of methods which may increase the feed efficiency is using of ionophores in feedlots. Monensin is a polyether ionophore produced by a strain of Streptomyces cinnamonensis that improves energetic efficiency of ruminal fermentation (Haney and Hoehn, 1967). There are limited studies to assess the effects of ionophores at farm conditions in Iran. The aim of this study was to assess the effects of monensin on fattening performance of Sarabi male calves. The monensin used in this experiment was supplied by Elanco Company.

The Dacron bag technique has been widely used to estimate degradation in the rumen. The drawbacks, such as variation in rinsing losses and inability to correct for microbial contamination, are well known. However, these effects also suggest the potential to use the technique in studies of microbial colonisation. Other studies in our laboratory have investigated the use of odd-chain fatty acids (C15:0 and C17:0) as markers of rumen microbial activity (Fievez et al, 2003) because they are generally rare or absent from feeds. The objective of this work was to use multivariate statistical analysis to explore the relationships between plant and microbial fatty acids in ingested herbage.

Results of a recent study (Wicks et al. 2005) indicate that increasing the protein content of the milk replacer fed to autumn-born Holstein-Friesian calves reduced growth rates in the first 8 weeks of life. Van Amburgh et al., (2001) previously suggested that increasing both milk replacer intake and protein content maximised the growth of calves during this early phase of life. An experiment was undertaken to investigate the influence of level of milk replacer and crude protein content on calf performance during the first 8 weeks of life of spring-born calves.

Data from the US (Van Amburgh et al., (2001)) suggests that the current UK recommendations for feeding the neonatal calf (˜500g milk replacer/d, at ˜230 g crude protein per kg fresh milk powder) are inadequate to sustain high growth rates in early life. It has been suggested that increasing nutrition during the first 6-8 weeks of the calf’s life will improve lifetime production, health and fertility. An experiment was therefore initiated to investigate the influence of level of milk replacer feeding and the crude protein content of the milk replacer on calf performance during the first 8 weeks of life, under UK conditions.

Grazing experiments have shown that using a ryegrass (Lolium perenne L.) variety bred by conventional techniques for high water-soluble carbohydrate (WSC) concentrations can improve liveweight gain in pre-weaned lambs (Lee et al., 2001) and increase milk yields and reduce N excretion in dairy cows (Miller et al., 2001) compared to conventional ryegrass. The aim of this study was to determine the effects of using reseeded upland pastures, sown with either a ryegrass variety bred for elevated levels of WSC or a control ryegrass on the production performance of grazing steers when compared to steers grazing permanent ryegrass/white clover pastures.

The Botswana Composite Breed (BCB) was developed by Dept. of Agricultural Research to mitigate problems of small herds that could not sustain crossbreeding programs. The breed has 47.5% Sanga, 22.6% Zebu and 29.9% Bos taurus blood. Indigenous Tswana cattle are 40% of the national herd (Masilo and Podisi 2001), indicating an erosion of local genetic material. Tswana cattle are small framed and are prejudiced by the Botswana Meat Commission (BMC) weight-based pricing system in favour of large-framed cattle. Lack of carcass characterization of indigenous cattle contributes to the above situation. The aim of this study was to evaluate performance of BCB and other indigenous breeds under feedlot and grazing conditions in order to promote their attributes.

Grass and forage maize are the most important fodder crops for feeding dairy cows. However, on drought prone sandy soils, and in years with insufficient rainfall the yield of maize is very low (7 to 8 tons DM/ha). In situations where water is a limiting factor for growing maize, triticale and barley may be an alternative fodder crop. Triticale grows mainly during the early spring when there usually is a precipitation surplus and so, water is not a limiting factor for growth. When triticale is harvested as triticale whole crop silage the DM yield ranges between 9 and 11 ton of dry matter per hectare. Therefore, under water limiting conditions it may be attractive to replace forage maize by triticale and barley whole crop silage. The objective of this study is to find the effects of replacing maize and barley silage by triticale whole crop silage on feed intake and milk production of lactating Holstein cows.

Canola meal (CM) proteins are extensively degraded in the rumen. Various physical and chemical treatments have been used to alter the rate of ruminal degradation of CM protein, thus decreasing rumen protein degradability and increasing the content of metabolizable protein. To our knowledge, little information is available concerning the effect of microwave treatment on the type of CM proteins that leaves the rumen undegraded. The main objective of our research was to evaluate the degradation of untreated and microwave treated CM proteins by using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE).

Proteolysis within plant cells occurs during wilting and drying. Changes in plant proteins during those periods usually are monitored by measurement of total crude protein and non protein nitrogen. Alternatively, changes in concentrations of individual proteins can be measured. Plants are composed of an array of different proteins. Electrophoresis can be used to separate these proteins and has been used to study effects of wilting and ensiling on proteins of some forages (Grum et al., 1991). Electrophoresis also has been used in the study of ruminal hydrolysis of oilseed meals proteins (Sadeghi et al., 2004). Most of the experiments designed to use electrophoresis to study protein metabolism in forages and ruminants have been qualitative. The main objective of this study was to determine whether sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and densitometry could be used to monitor quantitatively the changes in alfalfa protein composition during wilting, drying and ruminal exposure.

Micronisation or infrared processing has been used as a thermal process of feedstuffs. In this technology, feeds are subjected to rapid surface and internal heating by the application of infrared light. This energy is absorbed by the product and causes constituent molecules to vibrate, resulting in rapid internal heating. A major advantage of micronisation over other heat treatment methods is the shorter heating time applied during processing. The effects of micronisation of cereals on starch structure and digestibility of starch and crude protein (CP) and performance of pigs has been investigated (Zarkadas and Wiseman, 2001). However, data on ruminal starch and protein degradability of micronised cereals, especially corn grain are limited. Furthermore, the effect of micronisation on the type of corn true protein escaping from the rumen is lacking. The objectives of this study were to determine the effects of micronising corn grain on ruminal kinetic parameters of dry matter (DM), CP and starch and to determine the types of corn true protein escaping from the rumen to small intestine by using SDS-PAGE.