Carcass Weight Loss Research Articles

Bacon yield from fasted pigs

ABSTRACTCommercial crossbred pigs weighing about 80 kg and comprising equal numbers of females (gilts) and castrated males (castrates) were killed at a bacon factory 4 h (controls), 24 h or 48 h after food withdrawal. The carcasses from pigs fasted 24 h were on average 1·4 kg lighter, and those from pigs fasted 48 h, 2·9 kg lighter, than those of the control group. Fasting also reduced liver weight by about 0·3 kg but had no significant effect on backfat thickness or mean initial or ultimate pH in the muscles. Carcasses were cured into bacon by the Wiltshire process. Those from pigs fasted longer gained less weight after pumping with brine but also lost less weight during brine immersion and maturation. The overall yield of bacon, in relation to carcass weight, was therefore not affected by fasting. Consequently, the reduced carcass weight in the fasted pigs was carried through almost unchanged to the final yield of matured bacon. This was proportionately reduced by 0·019 in the pigs fasted 24 h and 0·043 in those fasted 48 h when compared with the control group.There was thus no evidence of any material reduction of yield differences during curing which could be caused by equilibriation of water in the carcass tissues with that in the curing brine. The implication is that losses in carcass weight in fasted pigs cannot be attributed simply to dehydration. Cured sides from fasted pigs tended to have proportionately slightly less weight in the ham and middle and more in the shoulder, and bacon from the pigs fasted 48 h was marginally less salty.

Inhibition of Tumor Growth by Zinc Depletion of Rats

Tumors grow less rapidly when implanted into zinc-deficient rats. The objective of this study was to determine if tumor growth is also inhibited when tumors first are established and then a zinc depletion initiated. Therefore, rats with palpable mammary adenocarcinomas or with sham implants were pair-fed either a control or zinc-deficient diet for 32 days. Rats were then killed and tumors, plasma and several tissues analyzed. In three separate experiments tumor growth was inhibited 32, 35 and 35%, respectively. The extent of tumor necrosis and tumor zinc concentration were not different between control and deficient groups. However, there was a significant positive correlation between tumor zinc concentration and percent viable tumor tissue in both groups. Although zinc depletion in tumor-bearing rats resulted in a 10% loss of carcass weight, there was little effect on liver, kidney and heart weights. As a result of depletion alone, zinc concentrations decreased only in plasma and kidney. As a result of tumor growth alone, concentrations of liver zinc increased and kidney copper decreased. In plasma of tumor-bearing rats, levels of zinc decreased 40% while copper and magnesium increased 50 and 13%, respectively. To our knowledge, this is the first demonstration that growth of established tumors can be retarded solely by dietary zinc depletion.

A comparison of boars, gilts and castrates for bacon manufacture 1. On farm performance, carcass and meat quality characteristics and weight loss in the preparation of sides for curing

ABSTRACTA total of 182 pigs from one farm and comprising 65 boars (B), 65 gilts (G) and 52 castrates (C) from 48 litters, were reared from birth to 89 kg live weight. Sex of pig did not influence age at slaughter but B compared with G and C had lower killing-out proportions (0·748 v. 0·756 v. 0·753) and reduced backfat measurements. Skin damage in transit to slaughter and/or in lairage was more prevalent in B compared with C, with G being intermediate. Muscle pH measurements were not influenced by sex except ultimate pH of the m. semispinalis capitis, where B compared with G and C had a higher incidence of values above 6·1 (0·246 v. 0·060 v. 0·120). Carcasses of B had proportionately more shoulder (0·04 unit) and more leg (0·011 unit), at the expense of middle, than those of C with G being intermediate. Weight losses in the preparation of de-boned sides for curing were higher in carcasses of B compared with G and C.

The influence of preslaughter fasting on carcass and liver yield in pigs

Landrace pigs (62 kg) were slaughtered immediately after feeding and at 9, 18, 24, 33 or 48 h after food withdrawal. Ambient temperature was 6.7 ± 0.61°C (SEM). Live weight began to be lost almost immediately and carcass weight between 9 and 18 h. The rates of loss between 18 and 48 h of fast were 0.21% of live weight and 0.11% of carcass weight per h. From chemical analysis of a rib chop the loss in carcass weight could not be identified specifically with loss of water, protein or fat. Pigs killed after longer fasts had carcasses which lost slightly less weight in chilling and had higher ultimate pH in the M. semimembranosus and M. adductor. Liver weight decreased rapidly over the first 24 h after food withdrawal (0.73% per h) and then almost stabilised. Practically all the glycogen in the liver was lost within the first 18 h and fat reserves were being mobilised by 9 h after food withdrawal. Haemoconcentration occurred with longer fast.

Reduction of carcass yield in transported pigs.

AbstractPigs (53‐70 kg) in a non‐fasted state were either not transported or subjected to a journey lasting for 1 h or 6 h prior to slaughter. Pigs given the short transport lost 0.6% and pigs given the long transport 2.3% of their initial live weight. After lairage for 1 h with access to water, all pigs were killed 8 h after their last feed. Compared with pigs not transported before slaughter, killing out percentage was slightly, but not significantly, lowered in the short transport group and significantly (P<0.05) reduced in the long transport group. The loss in carcass weight of the latter group amounted to 2.1% of the carcass weight of the untransported control pigs. Overall, killing out percentage and liver weight expressed as a percentage of liveweight were negatively correlated with the percentage loss of live weight in transport (P<0.02). The carcass weight loss on chilling was not influenced by treatment. Measurements of adrenal ascorbic acid suggested that most of the stress of transport occurred during the loading and first hour of the journey. Transported pigs drank more water in lairage, particularly those transported for 6 h which also had a higher total protein concentration in their plasma (P<0.05). Plasma creatine phosphokinase activity was not influenced by transport. It is suggested that enforced deprivation of water is an important contributing factor to the weight loss of pigs during transport but that physical activity is not.

Loss of carcass weight, liver weight and liver glycogen, and the effects on muscle glycogen and ultimate pH in pigs fasted pre‐slaughter

AbstractPigs (50–65 kg) were last fed 24, 16 or 1 h before transport to slaughter. The journey lasted 1 h and on arrival they were killed after either 1 h or overnight lairage. Although not statistically significant, carcass weight was greater in groups fasted least and those killed after 1 h lairage and these differences were reflected in significantly higher killing‐out percentages in these groups. Relatively rapid loss of both live and carcass weight commenced after about 18 h after the last meal, and it was concluded that, to prevent economically important losses, total time from last feed to actual slaughter, including transport and lairage, should not exceed this length of time. The rate of liveweight loss was approximately 0.21 % h−1 and the loss in carcass weight was 0.13% h−1 of fast. Longer lengths of fast significantly reduced liver weight, liver and muscle glycogen and raised muscle ultimate pH. Transport resulted in a large rate of loss in liveweight in proportion to that caused by fasting alone. Backfat thickness was not affected by any of the treatments.

Glucose Disposal and Gluconeogenesis From Alanine in Tumor-Bearing Fischer Gluconeogenesis 344 Rats<xref ref-type="fn" rid="fn2">2</xref>

For the study of glucose carbon recycling and incorporation of carbon atoms from plasma glucose, [3-3H]glucose and [U-14C]alanine were injected into inbred non-tumor-bearing (NTB) and tumor-bearing (TB) male F344 rats. The glucose and alanine kinetics were determined in relation to antecedent food intake and carcass weight loss. Whereas fed NTB and TB rats appropriately experienced reduced glucose disposal with decreased food intake (0.99 vs. 0.29 mg/min -100 g(-1) compared wtih observations in starved NTB rats), starved TB rats exhibited increased glucose utilization. Both fully fed and cachectic TB groups exhibited increased isotopic carbon recycling compared to the carbon recycling of NTB control groups, whereas starved TB rats did not demonstrate increased recycling compared to the carbon recycling (27% of C-atoms recycled). These findings suggest that alterations of glucose turnover, carbon recycling, and gluconeogenesis in the fed host parallel hypophagia and weight loss, regardless of TB status.

Tumor growth in experimental animals: nutritional manipulation and chemotherapeutic response in the rat.

The effects of nutritional manipulation on host body weight dynamics, tumor growth patterns and host-tumor responses to chemotherapy were studied in Sprague-Dawley rats with Walker-256 carcinosarcomas. Group I maintained throughout on a regular diet (RD) gained carcass weight steadily. Group II lost carcass weight while fed a protein-free diet (PFD) but rapidly gained weight after switching to RD on day 15. Mean tumor volume increased 105% in Group I from day 15 to 21, 218% in Group II and 77% in Group III (continued on PFD p less than 0.05). From day 21 to day 33 tumor growth patterns were similar in Groups I and II, while mean tumor volume eventually plateaued in Group III. In Study B, Group II animals were given Methotrexate (MTX-20 mg/kg) two days and six days after switching from PFD to RD. The mean change in tumor volume in the MTX-treated rats was 1.31 +/- 0.1 cm3 compared with 8.14 +/- 0.1 cm3 (p less than 0.001) in the saline-treated control rats. MTX did not significantly affect tumor growth patterns in Group III (PFD) rats. In Study A, protein-calorie malnutrition resulted in host carcass weight loss and tumor growth retardation while nutritional repletion restored host carcass weight and stimulated tumor growth. In Study B, MTX was maximally effective in tumor-bearing rats that were switched from PFD to RD demonstrating that nutritional manipulation can improve host nutritional status and increase tumor response to chemotherapy.

Effect of chronic protein malnutrition on host-tumor composition and growth

A protein-deficient diet (7%) was compared to a normal protein-content diet (24%) for changes in F 344 rat carcass, methylcholanthrene (MCA)-tumor growth, liver and tumor DNA and nitrogen content, and tissue DNA specific activity. Body weight gain in non-tumor-bearing protein-deficient animals was inhibited, while protein-deficient tumor-bearing rats exhibited similar growth characteristics with an increase in carcass weight loss during the final 3 days of observation (18–21 days). The concentration of host and tumor DNA was unaffected by diet whereas liver nitrogen concentration was reduced in both protein-depleted groups compared to regularly fed animals. Specific activity of tumor DNA from animals fed the protein-deficient diet was consistently greater than tumors of fully fed controls. Dietary protein restriction did not affect growth characteristics or composition of this MCA tumor, but retarded growth and lysed carcass protein of the host. These findings support efforts for nutritional repletion of the tumor-bearing host.

The effects of severe feed restriction on bulls and steers. I. Liveweight loss, behaviour and non-carcass body composition

The effects of substantial liveweight loss on the behaviour and body composition of half-sib Hereford bulls and steers were studied by using a serial slaughter technique and starting with nine animals—three bulls and six steers—of similar liveweights (mean 472 kg) but different fatness (the steers having appreciably more fat). Following the establishment of initial body composition by slaughter of a bull and two steers (group I), two bulls and four steers were given 0.91 kg of poor quality hay per day for 142 days. The six cattle all had similar liveweight losses (mean 170 kg) during this period, but the bulls were extremely emaciated and lethargic by day 142 while the steers were not. Slaughter and comparison of the pair of bulls with one pair of steers (group 2) at this time indicated a considerably greater loss of carcass weight and lesser loss of offal weight by the bulls than by the steers. The remaining pair of steers (group 3) continued to lose weight for a further 57 days, by which time they appeared as emaciated as the group 2 bulls had been, though not so lethargic. The proportions of feet, head and hide relative to carcass weight were significantly (P < 0.05) greater in bulls than steers, but there were no significant sex differences in the proportions of liver, spleen, heart or kidney. Except for the head, the interaction between weight loss and sexual status had no significant effect on offal proportions; the head percentage increased significantly more in bulls than steers during weight loss. The effect of progressive weight loss in the three groups of steers was a significant (P < 0.05) increase in the feet, head, hide, spleen and heart weights relative to carcass weight. It is concluded that from a management point of view, behaviour is a better guide to waning fat reserves than appearance, and that steers, because of their greater fat content, would survive a period of feed restriction longer than bulls of the same liveweight.

A comparison of body composition and tissue distribution of Friesian and Angus steers

SummaryFourteen Friesian and 13 Angus steers, grown at pasture, were selected so that their carcass weights fell evenly throughout the range 200–300 kg. The right half of each carcass was dissected into muscle, fat, bone and fascia and tendon, and the left half boned-out and fat trimmed into retail cuts. A step-wise multiple regression procedure, including a pseudovariable for breeds, was used to compare compositional components on a common weight basis.Angus, at the lower end of the live-weight range, had heavier empty bodies than Friesians; at the heavier end of the live-weight range, this was reversed. This relationship between live weight and empty body weight was due to variation between breeds in the weight of contents in the fore stomachs but not the intestines.When compared at either the same live weight or the same empty body weight, Angus had more hot carcass than the Friesians (8·0 and 8·4 kg, respectively). There was no difference between breeds in loss of carcass weight in the 24 h post-slaughter.There was no breed difference in weight of blood, head, kidney and channel fat, kidneys, liver, diaphragm, heart, lungs, tail or fore-stomachs, when compared at the same offal weight. The feet and intestines were, respectively, 0·55 and 2·43 kg heavier for Friesians than for Angus at the same offal weight, but the pizzle was 0·11 kg lighter. Hide weight was greater in the Angus at all offal weights, with the difference between breeds being 0·016% of (offal weight).There was no difference between breeds in the weight of muscle or the weight of fascia and tendon when compared at the same dissected side weight; however, the Angus had 4·8 kg more fat and 3·0 kg less bone than the Friesians at the same dissected side weight.When compared at the same muscle weight the Friesians had 1·04 kg more proximal hind-limb muscles, 0·30 kg more proximal fore limb muscles, but 0·74 kg less abdominal muscles than the Angus. At all dissected muscle weights the Angus had a greater weight of muscles of the neck and thorax, and this difference increased with increasing weight of dissected muscle. The Friesians also had 1·52% more of their muscle as ‘expensive muscle’. There were no breed differences in the distribution of any other muscle groups.There was no breed difference in the distribution of dissected fat between subcutaneous and intermuscular depots when these were the only fat depots considered. However, when kidney and channel fat was included in the total dissectable fat of the carcass, Friesians had 22·4 % more kidney and channel fat, the same weight of intermuscular fat and less subcutaneous fat than the Angus at the same total dissected fat weight.Friesians tended to have more of their bone weight in their legs (humerus, femur, tibiar–tarsus, radius–ulnar–carpus) and Angus more in their thoracic region (thoracic vertebrae and ribs, scapular and sternum-costal cartilages).At the same retail side weights there was no difference between breeds in the weight of fat-trimmed, boned-out, retail cuts; however, the Friesians had 3·3 kg more retail bone than Angus, but 2·3 kg less fat trim and 0·46 kg less sausage mince.There was no difference between breeds in the distribution of retail bone or of fattrimmed, boned-out cuts between the forequarter and hindquarter. However, the Friesians had 13·2 % more fat trim in the hindquarter. Friesians had 0·27 kg more retail cuts located in the rump but 0·80 kg less in the loin, when compared at the same weight of retail cuts. Also, the Friesians had more of their retail cuts as topside, thick flank and foreshin. There were no other differences between breeds in the distribution of retail cuts.

Weight Loss of Fed Steers during Marketing

AbstractFeeding and marketing practices are related to weight loss of fed steers during marketing. Liveweight and carcass weight losses are higher if feed and water are withheld from steers before slaughter. Packers have incentive to require this practice because the liveweight‐cost reduction exceeds the value of the lost weight.

Weight losses from milk and weaned lambs in mid canterbury resulting from different lengths of starvation before slaughter

Abstract Three experiments, using in total 388 lambs, were completed in mid Canterbury. Weight losses resulting from different lengths of preslaughter fasting were measured on weaned lambs in March 1969 and on unweaned lambs in November and December 1969. Results of the trials show. 1. That there appeared to be no difference between weaned and unweaned lambs in the starvation time needed to initiate carcass weight losses, and in the rate of carcass weight loss once it had started, for lambs down to 11 weeks old. 2. That in all experiments more than ½ lb of carcass weight had been lost 24 hr after removal of lambs from pasture. This loss increased to 1.1-1.61b after 2 days' fasting. 3. A major determinant of when carcass losses start after siarvation has begun seems to be the amount of stomach “fill” when lambs are removed from pasture.