Publisher Summary The chapter discusses that meat has occupied a unique position in the human diet since man's primitive beginning. Today it is still regarded as an important ingredient of any menu. From the deep surface of the epimysium, septa pass frequently into the muscles at irregular intervals. These septa, which constitute the perimysium, invest the primary bundles (fasciculi) of muscle fibers. Muscle cells contain a large variety of proteins with many of them involved in the glycolytic pathway of muscle metabolism and the contraction-relaxation process. The fibers of striated muscle are elongated and more or less tubular, and vary in size and shape. The subject of meat quality has become increasingly scientific with less reliance now being placed on personal judgment and more on physical and chemical tests. According to Kramer and Twigg, the quality of a food may be defined as the composite of those characteristics that differentiate individual units of a product and have significance in determining the degree of acceptability of those characteristics by the consumer. Meat production is fundamentally based on the growth process from the time of fertilization of the ovum until the animal has reached the final age and stage of development determined by its genetic potential. This chapter discusses that the physical, chemical, and histological properties of muscle change markedly during the first 24 hours following slaughter. Complete bleeding is very important as blood provides an ideal medium for the multiplication of bacteria and facilitates their distribution throughout the carcass.

Influence of Ante- and Postmortem Treatments Upon Muscle Composition and Meat Quality

This paper reviews the literature comparing growth performance, carcass, and meat quality data between barrows and boars. Compared with barrows, boars have reduced feed intake, improved feed efficiency, less backfat, higher nitrogen retention, and leaner carcasses. Growth rate of boars will be higher than that of barrows if adequate dietary amino acids are supplied. The improved growth performance and carcass characteristics of boars are primarily due to the anabolic effects of androgens and estrogen produced in the testis. However, administering manufactured anabolic agents, androgens, and estrogens to barrows has not yet been shown to improve growth and carcass in swine.

/pdf/performance-carcass-and-meat-quality-advantages-of-boars-225c1m9brr.pdf

Performance, carcass, and meat quality advantages of boars over barrows: A literature review

1. Measurements of energy and nitrogen balances were made on thirty-eight individually housed pigs (initial body-weights 21–38 kg) at environmental temperatures of 10, 15, 20, 25 and 30° with four levels of feeding at each temperature. Values for energy retention (ER), protein (P) and fat (F) deposition and body weight gain (δW) were calculated at each temperature at metabolizable energy (me) intakes equivalent to once (M; 440 kJ/kg0.75 per d), twice (2M), three (3M) and four (4M) times the thermoneutral maintenance energy requirement.2. ER at each plane of nutrition increased with temperature to maximal values between approximately 20 and 25° ER was negative at four of the five environmental temperatures at M.3. P increased significantly with increase in me intake but was dependent on environmental temperatures only at intakes of M and 2M. The increase in P per unit increment in me intake decreased from 0.16 at 10° to 0.12 at 30°. The net efficiency of protein utilization also decreased with increase in environmental temperature from 0.54 at 10° to 0.39 at 30°.4. F increased significantly with increase in me intake, but was more temperature-dependent than P, increasing to maximum values estimated to be between 20 and 25° at each level of intake; F at 30° was less than that at 25°. The increase in F per unit increment in me intake decreased from 0.63 at 10° to 0.51 at 30°.5. The optimum temperature for ΔW was dependent upon me intake, varying from above 30° at M to less than 20° at 4M. The reduction in ΔW per 1° at 15° was also dependent upon the level of intake decreasing from 1.63 g/kg0.75 per d at M to -0.09 at 4M.6. For a 35 kg pig the reduction in P, as a result of a 1° decrease in temperature at 15° at an intake corresponding to 2.5M, was equivalent to a 4 g/d reduction in food intake; the corresponding equivalent for F was 28 g/d.

/pdf/the-effects-of-plane-of-nutrition-and-environmental-wrorl5vbwu.pdf

The effects of plane of nutrition and environmental temperature on the energy metabolism of the growing pig: 2*. Growth rate, including protein and fat deposition

One hundred and forty-two kids of the Damascus breed of goat were used over a 10½-mo period to study the effects of early castration (at 7 days of age) on growth, feed conversion efficiency and carcass quality and late castration (at 7½ mo of age) on the presence or absence of taint in goat meat.Intact male kids grew faster and used feed more efficiently than castrates until they were about 9 mo old (56 kg live weight). There- after intact kids exhibited strong sexual activity and as a result their growth ceased completely whereas castrates continued growing. Early castrates produced fatter carcasses than those of intact kids. Castration of male kids at the age of about 7½ mo (44 kg live weight) was not successful in this trial and the kids performed very poorly. A taint of varying intensity was present in the meat of intact goats but not in that from any of the early or late castrates.

Effects of castration on growth rate, feed conversion efficiency and carcass quality in Damascus goats

Chapter 9 – Amino Acids in Swine Nutrition

Castration of males is a long-established practice in animal husbandry, and although the use of boars rather than hogs was advocated by Fitzherbert in 1534 the use of castrates in pig production has continued to the present day.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002185960006473X

The effect of sex on growth and carcass quality in the bacon pig.

A total of 512 pigs were given from 50 lb live weight one of 16 diets, i.e. with 4 lysine levels at each of 12, 14, 16 and 18% protein, at one of 4 levels of intake. They were killed at 100, 150, 200 or 250 lb live weight.Live-weight gain was not improved significantly by increasing the protein level above 16, 14, 12and 12%, respectively, for the 50–100, 100–150, 150–200and200–2501bstages. However, conversion of feed to live-weight gain was improved significantly during the 50–100 lb stage by increasing the protein to 18%. Gain in lean meat and in the efficiency of conversion of feed to lean meat were improved by increasing the above protein levels slightly.Live-weight gain was not improved significantly by increasing the lysine level above 1·04, 0·74, 0·70 and 0·59%, respectively, for the 50–100, 100–150, 150–200 and 200–250 lb stages. However, conversion of feed to live-weight gain was improved significantly during the 50–100 lb stage by increasing the lysine level to 1·22%. Raising the lysine level at each level of protein had no significant effect on the rate and efficiency of lean meat gain.Live-weight gain was significantly improved by increasing the level of feed intake almost to ad libitum levels for the 50–100, 100–150 and 150–200 lb stages. There was a suggestion of a similar effect in the 200–250 lb pigs although it was not statistically significant. Conversion of feed to live-weight gain was improved in the 50–100 lb pigs only by increasing the level of feed intake: in the older pigs increasing the level of feed intake caused a worsening in feed conversion ratio. Increasing the level of feed intake gave a significant improvement in rate of lean meat gain but a significant worsening in the efficiency of conversion of feed to lean meat during all stages up to 200 lb.Interaction effects of these factors and sex, on growth performance, are described.

Protein, lysine and feed intake level effects on pig growth: I. Main effects

A total of 512 pigs were given from 50 lb live weight one of 16 diets (four lysine levels at each of 12, 14, 16 and 18% protein), at one of four levels of intake. They were killed at 100, 150, 200 or 250 lb live weight and the carcasses jointed in a standard manner and right sides dissected into lean meat, fat, skin and bone. Mean percentage proportion of shoulder, middle and ham joints in the dressed sides at the four weights was 36·3, 36·4 and 27·3; 35·4, 37·9 and 26·7; 34·5, 39·6 and 25·9; and 33·8, 40·7 and 25·5, respectively. Mean percentage lean meat at the four live weights was 61·5, 59·9, 56·7 and 54·2 and the mean percentage fat was 20·7, 24·4, 29·4 and 32·8. Carcass quality was influenced significantly by dietary treatment and sex. Increasing the level of protein in the diet up to 16, 16, 14–16 and 14%, respectively, for the four live weight groups gave a significant increase in carcass leanness. Increasing the level of lysine in the diet did not have a very marked effect on carcass composition, while increasing feed intake to the highest level produced fatter carcasses at all weights. Carcasses of males were fatter and with a lower proportion of ham than those of females. Interactions involving dietary treatments and sex were described. Chemical composition of the m. longissimus dorsi was not altered markedly by dietary treatment or sex but dry matter and intramuscular fat content rose with increasing weight. Protein content of the dry matter remained fairly constant at all weights, while colour and shear value rose with increasing weight but were not significantly influenced by dietary treatment or sex. The pH values of the m. multifidus dorsi just after slaughter or on the day following were not markedly affected by dietary treatment, sex or weight.

Protein, lysine and feed intake level effects on pig growth: II. Effects on carcass composition and quality

SUMMARY Data from the experiment described in the first paper of this series were subjected to regression analysis. Lean meat and live-weight gain response to both lysine and crude protein intake was almost linear in period 1 but in later periods little response was evident. Response of live-weight gain to increased energy was continuous though diminishing in the later periods. In periods 1 and 2 lean gains showed positive though diminishing response to energy. In a multivariate regression analysis it was clear especially for younger pigs that the response to dietary lysine for both live-weight and lean meat gains is influenced by the dietary level of crude protein and the energy intake. Separate multivariate analysis for each sex indicated that females are more efficient converters of lysine and energy into live weight and lean meat. Also an interaction between sex and dietary lysine level was suggested. A methodology for an economic analysis taking the joint objectives of total cost of production, speed of grain and quality of gain is established as a basis for design of high profit system of production.

R. Blair

Papers

The effect of sex on growth and carcass quality in the bacon pig.

Protein, lysine and feed intake level effects on pig growth: I. Main effects

Protein, lysine and feed intake level effects on pig growth: II. Effects on carcass composition and quality

Protein, lysine and feed intake level effects on pig growth. III. Regression analysis and economic aspects