Growth of farm animals

Abstract

Index x Contents Preface to First EditionAn understanding of the processes which change the size, shape and composition of farm animals is fundamental to all aspects of production which seeks to meet the dietary and other needs of human populations. This book attempts, within the limits of a basic undergraduate text, to give a comprehensive picture of how animals grow, change in shape and in composition, and to describe those factors which affect growth processes and which dictate the extent and direction of changes within the animal.The overall scene we have attempted to present is a progression from cell to tissue to entire animal, as well as a description of those factors within the animal, particularly hormones, genes and gender, which fashion this progression. In addition, an attempt has been made to give perspective to the manner in which such a complexity of changes affects the approach to, and understanding of, concepts of efficiency. However, it was felt that the framework would not be complete without first setting the scene in the context of some of the principles which govern size and shape in all animals and, second, describing the methods which may be used to measure the overall results of the processes which have been described. Deliberately, the effect on growth which exogenous factors such as hormonal implants, antibiotics and other intestinal tract manipulators may have has not been considered. Although the use of such manipulators may be transitory and dependent on political and other pressures, basically they were not considered to be appropriate to the general thesis. Whilst it is acknowledged that poultry are farm animals of great importance in producing food for the human, largely through a dearth of appropriate detailed information and because of the approaches to production which are used in practice, this book concentrates on cattle, sheep and pigs.In our student days we were endlessly fascinated by the seminal studies of D'Arcy Thompson, by the profound work of Brody at Missouri and by the inspired and inspiring work and writing of Hammond and his associates at Cambridge. To no less an extent we found the sheer variety of animal cells and the immensely complex tissues that they form, and which give ultimately the overall growth responses, both amazing and mind gripping. These fascinations have remained with us ever since and in our working lives we have been fortunate to have had the chance to make some contributions to some of those areas which have so consistently intrigued us and occupied our thoughts. As students the writings of those great men above were those to which we turned. Today much of their basic thinking still holds good and leads the enquiring mind in the right direction when considering the problems of how best farm animals may be grown to yield products for the human. However, there is no book which as a complete entity has updated their basic thinking and which takes the reader from cell to complete animal based on original classical anatomical studies and the quantit...

Tissue and plasma antioxidant status in response to dietary methionine concentration and source in broilers

“…Similarly, the higher relative weights of liver, kidney and small intestine in the Met− group can be explained by the suboptimal Met supply, which reduced muscle growth, but not the absolute weights of the internal organs. This is consistent with the view that the gastrointestinal tract and several internal organs in young animals have a high growth priority relative to muscle and fat tissue (Lawrence, Fowler, & Novakofski, 2012;Lilja, 1981).…”

Effects of the plane of nutrition for grower pigs on their grow-finish performance and meat quality in winter

“…The greater pH value for the LP group vs. MP in the present study was thus seemingly partially associated with the greater fat content in the former, although the difference between the two groups in fat content was not significant. Nonetheless, these results, as well as the greater protein content for the MP vs. LP group, are thought to be more of a mathematical significance rather than quality, in that the numerical differences between the two groups in the pH value and protein content were minimal within the normal ranges for the normal pork [14, 37, 38]. It needs to be noted, however, that the greater juiciness of cooked LM for the LP group vs. HP and MP groups is likely to have resulted from the greater WHC of fresh LM for the LP group, because WHC is one of the main factors enhancing the juiciness of cooked meat [38].…”

“…Furthermore, a compensatory growth usually occurs when the grower pigs fed a diet with a low lysine:- calorie ratio switch to a diet with a normal lysine:calorie ratio. The compensatory growth is frequently, but not always, concomitant with an increased feed intake and an increased fat deposition [13, 14], even though the fat deposition can be down-regulated during the compensatory growth for a compensatory lean gain which has priority over the energy retention [11, 15–19].…”

Effects of the slaughter weight of non-lean finishing pigs on their carcass characteristics and meat quality

“…It has been reported that the increase of SW results in a decreased production cost per unit weight of pork accompanied by slight increases in the dressing percentage and the yield percentage of the belly although growth rate and feed efficiency decrease following the increase of SW due to increased fat deposition [ 1 , 4 , 6 , 8 , 32 ]. It was therefore the rationale of the present study that if CW could be increased separately from the carcass grading system, the profitability would improve and the flavor of the meat might also improve [ 12 , 34 ], resulting in the improvement of pork quality, as was expected of the carcasses from the Hi and XHi groups of the present study mostly exceeding the 97-kg upper limit of Grade 1.…”

“…The SW seemingly influences meat quality primarily through its effects on fat metabolism. Intra-muscular fat (IMF), which increases marbling of fresh meat as well as the sensory attributes of cooked meat, including flavor, is known to increase with an increase in SW [ 11 , 12 ]. The IMF in the pork loin in the previous studies [ 4 – 7 ] indeed increased with the increase of SW, albeit to a limited extent, which did not influence sensory properties of cooked meat [ 8 ]; limited data regarding IMF for the ham precluded any assessment regarding the effect of SW on meat quality.…”