Ovulation rate of ewes : role of energy and protein

Western Australia\u27s sheep farmers are familiar with the low ovulation rate of Merino ewes and how this limits the lambing performance of ewe flocks. One way in which ovulation rate and therefore lambing percentage may be increased is to feed seed of sweet lupin (Lupinus augustifolius) to ewes at mating. However, Department of Agriculture research has found that these increases do not show up consistently, and that there is considerable variability between farms. If improved nutrition is to be a useful way to increasing ovulation rate, the mechanism by which nutrition affects ovulation rate must first be understood. This article describes the initial stages of a Department of Agriculture research programme designed to investigate this biological phenomenon. The question asked first was which of the many nutrients provided by lupin seed was the one responsible for the increase in ovulation rate? This was tackled by measuring the amount of each major nutrient available to sheep when lupins were given as a supplementary feed. These nutrients were then given one by one, in a purified form, to sheep to determine which nutrients resulted in increased ovulation rate

Glucose Metabolism in Sheep Fed Grass Supplemented with Gliricidia Sepium

The limiting factor on improving ruminant production for most of the available feed in developing countries are low in quality. Therefore high fibre diet must be supplemented by high nutritivefeed such as leguminous trees that much available in those regions. Gliricidia sepium was one of very potential candidates. Glucose as a major energy source in fed animals required precursor in form of propionat and amino acids from diet. Those precursors might be supplied by these legume leaves. The aim of this research was to investigate the glucose metabolism in the sheep fed grass supplemented by Gliricidia sepium. Fifteen sheeps (18 months old) were used in the experiment. Theseare were divided into three groups that fed by experimental diet of Mitchell grass (MG group), Gliricidia(GS group), and MG supplemented with GS (MGGS group). D-[U-14C]glucoseinfusate was infused continuously through the left jugular venous catheter of each animal to measure glucose metabolism in those sheeps. The measurements were done on feed utilisation and glucose metabolism. The results indicated that there was an improvement in efficiency of feed utilisation in the MGGS group as reflected by lower feed conversion ratio by the group. Plasma glucose concentration profile per unit of OM intake were similar for GS and MGGS groups, but higher than that in the MG group (P<0.01). Glucose entry rate (GER) increased in MG group through GS to the MGGS group, while N retention accordingly was increased. It can be concluded that theutilization of GS by the ruminant animal could be improved by feeding it with a low quality feed at a ratio of 40:60 (GS:Low quality feed) to achieve an NI:DOMI ratio of 0.03 - 0.04. This improvement would be manifested in increasing DOMI, with subsequent increase in GER or net protein deposition as might be expressed in positive N retention. Received: 8 October 2014; Revised: 12 December 2014; Accepted: 24 December 2014 

Amino Acids Metabolism in the Muscle of Sheep fed with Mitchell Grass Hay Supplemented with Gliricidia sepium

Leaf of Gliricidia sepiumcontains high amino acid that required for protein synthesis in the muscle. Supplementation of the legume leaves to low quality basal diet would improves amino acids amount to obtain an optimum growth of animal. The aim of experiment was to investigate the effect of Gliricidia sepium leaves supplementation to low quality basal diet on protein synthesis in muscle of animal. Eighteen sheeps were divided into three groups based on live weight (27.6 ± 1.72, 27.1 ± 2.26 and 27.5 ± 1.56 kg) of feed treatment, namely Mitchell grass hay (MG), Gliricidia (GS),and haycombined with Gliricidia (MGGS). All the dietwas offered with the amount was determined to meet the maintenance metabolizable energy (ME) requirement of the animals. Feed utilization and amino acid metabolism in muscle of sheep was measured with radioactively labeled leucine, water and sodium bicarbonate. Results indicated that sheepin MG group had a negative energy balance, whereas sheep in MGGS group had the highest amount of ME available for growth. The rate of protein synthesis was higher in the MGGS group and tended to take up these amino acids in their hind-limb muscles, while animalsin MG and GS groups tended to have net outputs of amino acids from their hind-limb muscles. Animals in the MGGS group synthesised more protein in their muscle than those in the GS and MG groups. It was concluded that the supplementation of Gliricidia at a ratio of 40:60improved feed utilization of low quality basal diet. The improvement would be manifested in better digestible organic matter intake (DOMI) with subsequent better utilization of amino acids

The sustainability of changes in agricultural technology:The carbon, economic and labour implications of mechanisation and synthetic fertiliser use

New agricultural technologies bring multiple impacts which are hard to predict. Two changes taking place in Indian agriculture are a transition from bullocks to tractors and an associated replacement of manure with synthetic fertilisers. This paper uses primary data to model social, environmental and economic impacts of these transitions in South India. It compares ploughing by bullocks or tractors and the provision of nitrogen from manure or synthetic urea for irrigated rice from the greenhouse gas (GHG), economic and labour perspective. Tractors plough nine times faster than bullocks, use substantially less labour, with no significant difference in GHG emissions. Tractors are twice as costly as bullocks yet remain more popular to hire. The GHG emissions from manure-N paddy are 30 % higher than for urea-N, largely due to the organic matter in manure driving methane emissions. Labour use is significantly higher for manure, and the gender balance is more equal. Manure is substantially more expensive as a source of nutrients compared to synthetic nutrients, yet remains popular when available. This paper demonstrates the need to take a broad approach to analysing the sustainability impacts of new technologies, as trade-offs between different metrics are common

Acetate and glucose entry rates in sheep fed a lupin supplement

The high protein content of lupin seed has been suggested (Lindsay, 1976) to be the principal stimulus in dramatic increases in ovulation rate (OR) in ewes fed a lupin supplement of between 250 g/hd/d and 750 g/hd/d for six to seven days. Subsequently studies to describe the pattern of digestion of the lupin protein (Lindsay et al., 1980) and nitrogen balance (Searle and Graham, 1980) in sheep fed a lupin supplement were carried out. Studies in our laboratory (Rowe et al., 1983) suggest that increased metabolisable energy (ME) may be the more important nutritional stimulus in increasing OR. This study was aimed at measuring the entry rates of acetate and glucose in lupin supplemented ewes with the view of using the data to study the effect of intravenous infusion of the two substrates on OR

Lactic acid and fatigue in working sheep

[Extract] In a previous study (1) it was suggested from data on the concentration of circulating plasma lactic acid that fatigue in the working buffalo was probably caused by the accumulation of lactic acid in the muscles of the limbs of the animal. The suggestion was largely speculative as no examination of the flux of lactic acid into and out of, or its accumulation in the limb muscles was undertaken. This study, using sheep as the rumninant model was therefore conducted to examine the flux of lactic acid across the working hind-limb muscles