The difference in energy metabolism between barrows and gilts and its effect on fat deposition and carcass quality
Date
1992
Authors
Journal Title
Journal ISSN
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Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: In a 2x5 factorial experiment undertaken with 50 Large White x Landrace pigs, growth rate, FCR and commercial carcass yields were evaluated, while a chemical analysis of a sample slice between the 5th and 6th rib was performed. The experiment was divided into 5 groups, each containing 5 barrows and 5 gilts. Group 1 received the control ration with high energy (13,3 MJ ME/kg) and high protein (20,7%) without added fibre (in the form of saw dust). The energy and protein content decreased progressively for the 5 rations and the saw dust increased correspondingly. The pigs were fed ad lib with free access to water and were slaughtered at 86kg. Barrows were found to have significantly (P<0,05) heavier belly fat and skin masses than gilts, while the interaction between sex and nutrient density was almost at the significant level (P=0,05) with the P2 measurement. The differences between nutrient densities proved to be greater than the differences between sexes due to the low number of experimental animals used. Regression equations showed that the saw dust and protein content of the rations were more accurate predictors of the carcass yields, on-farm performance results and chemical analysis and linear measurements of the sample joint than the ME. Days to slaughter were predicted with R2-values of 29,7%; 30,0% and 21,6% when saw dust, protein and ME, respectively, were used as independent variables. Barrows tended to have higher R2-values than gilts with intermediate values for the sexes calculated together. The saw dust and protein content were the most accurate independent variables for both barrows and gilts when used in a multiple regression, while ME did not contribute usefully to the accuracy when combined in a multiple regression. When the chemical composition of the sample joint was used as the independent variable, the highest R2-value (36,1%) was obtained when the shoulder fat and skin mass was predicted by the % moisture. Of the linear measurements of the sample joint, eye muscle area was the most accurate predictor of the carcass yields (R2for loin spare rib = 29,0%). Due to a high correlation between linear measurements and chemical analysis results of the sample joint, linear measurements were used as independent variables to predict carcass yields. Eye muscle area achieved the highest R2-values (shoulder fat and skin = 27,6% and loin spare rib = 29,0%).
AFRIKAANSE OPSOMMING: In 'n faktoriale proef, uitgevoer met 50 Groot Wit x Landras varke, is groeitempo, voeromsettingsverhouding en kommersiële karkasopbrengste geëvalueer. Daar is ook chemiese analieses van 'n monster tussen die 5de en 6de rib uitgevoer. Die proefdiere is verdeel in 5 groepe, elk met 5 burge en 5 sôe. Die kontrole rantsoen met 'n hoë energie (13,3 MJ ME/kg) sowel as hoë proteïen inhoud (20,7%) sonder bygevoegde vesel (in die vorm van saagsels) s vir groep 1 aangebied. Die energie- en proteïen inhoud het progressief or die 5 rantsoene verlaag terwyl saagsels ooreenstemmend verhoog het. Rantsoene is ad lib aangebied en water was vrylik beskikbaar. Varke is op 86kg massa geslag. Buikvet- en velmassa was betekenisvol (P<0,05) hoër by burge as sôe, terwyl die interaksie tussen geslag en voedingsdigtheid net bokant die betekenisvolle vlak (P>0,05) met P2-meting was. Die verskille tussen voedingsdigthede was groeter as geslagsverskille as gevolg van die klein aantal proefdiere gebruik. Progressievergelykings het getoon dat saagsel- en proteïeninhoud van die rantsoene meer akkurater voorspellers van karkas opbrengs, voedingsproefresultate asook chemiese analises en linieêre metings van die monster as ME - inhoud is. Indien saagsels, proteïen en ME gebruik is as onafhanklike veranderlikes om die aantal dae tot slag voorspel, was die R2-waardes onderskeidelik 29,7%; 30,0% en 21,6%. R2-waardes was hoër vir burge as sôe, terwyl waardes bereken vir burge en sôe tesame, intermedieêr was. Die saagsel- en proteïeninhoud was die mees akkurate onafhanklikes vir beide burge en sôe indien gebruik in 'n veelsydige regressie vergelyking. Indien ME hierby gevoeg is, het die voorselling van skouervet en velmassa deur die % vog die hoogse R2-waarde (36,1%) gelewer. Oogspieroppervlakte was die mees akkurate linieêre voorspeller van die karkasopbrengste (R2 van lendestuk = 29,0%). Weens die hoë korrelasie tussen linieêre metings en chemiese analises van die monsters is eersgenoemde gebruik as onafhanklike veranderlikes om karkasopbrengste te voorspel. Oogspieroppervlakte het die hoogste R2-waardes getoon (skouervet en vel = 27,6% en lendestuk = 29,0%).
AFRIKAANSE OPSOMMING: In 'n faktoriale proef, uitgevoer met 50 Groot Wit x Landras varke, is groeitempo, voeromsettingsverhouding en kommersiële karkasopbrengste geëvalueer. Daar is ook chemiese analieses van 'n monster tussen die 5de en 6de rib uitgevoer. Die proefdiere is verdeel in 5 groepe, elk met 5 burge en 5 sôe. Die kontrole rantsoen met 'n hoë energie (13,3 MJ ME/kg) sowel as hoë proteïen inhoud (20,7%) sonder bygevoegde vesel (in die vorm van saagsels) s vir groep 1 aangebied. Die energie- en proteïen inhoud het progressief or die 5 rantsoene verlaag terwyl saagsels ooreenstemmend verhoog het. Rantsoene is ad lib aangebied en water was vrylik beskikbaar. Varke is op 86kg massa geslag. Buikvet- en velmassa was betekenisvol (P<0,05) hoër by burge as sôe, terwyl die interaksie tussen geslag en voedingsdigtheid net bokant die betekenisvolle vlak (P>0,05) met P2-meting was. Die verskille tussen voedingsdigthede was groeter as geslagsverskille as gevolg van die klein aantal proefdiere gebruik. Progressievergelykings het getoon dat saagsel- en proteïeninhoud van die rantsoene meer akkurater voorspellers van karkas opbrengs, voedingsproefresultate asook chemiese analises en linieêre metings van die monster as ME - inhoud is. Indien saagsels, proteïen en ME gebruik is as onafhanklike veranderlikes om die aantal dae tot slag voorspel, was die R2-waardes onderskeidelik 29,7%; 30,0% en 21,6%. R2-waardes was hoër vir burge as sôe, terwyl waardes bereken vir burge en sôe tesame, intermedieêr was. Die saagsel- en proteïeninhoud was die mees akkurate onafhanklikes vir beide burge en sôe indien gebruik in 'n veelsydige regressie vergelyking. Indien ME hierby gevoeg is, het die voorselling van skouervet en velmassa deur die % vog die hoogse R2-waarde (36,1%) gelewer. Oogspieroppervlakte was die mees akkurate linieêre voorspeller van die karkasopbrengste (R2 van lendestuk = 29,0%). Weens die hoë korrelasie tussen linieêre metings en chemiese analises van die monsters is eersgenoemde gebruik as onafhanklike veranderlikes om karkasopbrengste te voorspel. Oogspieroppervlakte het die hoogste R2-waardes getoon (skouervet en vel = 27,6% en lendestuk = 29,0%).
Description
Thesis (M. Sc. Agric.) -- University of Stellenbosch, 1992.
Keywords
Livestock -- Carcasses -- Quality, Swine -- Carcasses -- Quality, Energy metabolism, Swine -- Feeding and feeds, Meat -- Quality, UCTD