A study on certain factors that may affect the production and feed intake of breeding ostriches

Tesselaar, Ger-Mari Alice (2015-03)

Thesis (MSc)--Stellenbosch University, 2015.

Thesis

ENGLISH ABSTRACT: A large amount of research has gone into developing growth models for other monogastric animals, incorporating various biological and animal related factors, feed factors, the environment as well as the interaction between these factors. In order to develop a mathematical optimization model for breeding ostriches, all possible factors that can influence feed intake and production needs to be investigated. Therefore this study was conducted to identify and quantify the possible factors that affect feed intake and production of breeding ostriches. In the first study (Chapter 3), the effect of certain nutrients on feed intake and production of breeding ostriches was evaluated. No specific effect of any one of the tested parameters (additional vitamins, minerals, fatty acids and amino acids) was seen on the production parameters considered. Significant differences were found in the quantity of feed ingested indicating a possibility that breeding ostriches may adjust feed intake to satisfy mineral requirements. The supply of additional vitamins and minerals during the resting period might have an effect on the results. Therefore, the second study (Chapter 4) determined the effect of the addition of minerals and vitamins during the resting and breeding period on the production of breeding ostriches. The presence of a vitamin and mineral premix during the resting period decreased body condition lost by female breeding ostriches with 31.2% and decreased the presence of DIS eggs with 8.1%. The supply of vitamins and minerals in the breeding period decreased the body condition lost by breeding females with 5.3%. Overall it can be concluded that the presence of a vitamin and mineral premix is essential in resting as well as the breeding period. The commonly used protein source in the diet of breeding ostriches, soya oilcake (SOC), has become so expensive that an alternative protein source, cottonseed oilcake (CSOC), was investigated for its possible use in the third study (Chapter 5). Cottonseed oilcake as a protein source had no significant effect on most of the production parameters (total number of eggs, DIS eggs, infertile eggs or chick production), but led to a significant decrease in the quantity of chicks hatched. Until more research results are available, it is suggested that producers follow the precautionary approach and not use CSOC to feed breeding ostriches. With the development of a simulation model for ostriches, the immediate effect of dietary energy content on feed intake as well as its long term effect on breeding ostrich production was determined in the fourth study (Chapter 6). One hundred ostrich breeding pairs were divided into five groups of twenty breeding pairs each for two consecutive breeding seasons and received one of the five experimental diets ad libitum. Although previous studies of Brand et al. (2002, 2003) have indicated that production in the current breeding season can be affected by nutrition of previous breeding seasons, no such effect was seen on the production parameters measured (total egg production, DIS eggs, infertile eggs, chick production, breeding female ostrich weight change or feed intake). Breeding ostriches also showed no indication of regulating feed intake according to the energy content of the feed. Literature revealed that breeding ostrich feed intake may be influenced by the bulk density of the feed. Due to lack of differences in production parameters measured, possible future studies can include the effect of low and high levels of basal energy supplied over three or more consecutive breeding seasons. Egg production is a costly process for female breeding ostriches, requiring high levels of quality feed and often causing loss of body condition. In study five (Chapter 7), the egg laying pattern for breeding ostriches was evaluated. Results from this study indicated that the days until first egg and total days in lay are strongly influenced by the age of the female ostrich. However, due to the egg production of female breeding ostriches being highly variable, and a vast number of factors influencing the production of ostrich eggs, a specific egg laying pattern over the breeding season could not be identified. This thesis makes a significant contribution towards quantifying the factors affecting production and quality parameters in breeding ostriches. Most of the results obtained in these studies can be incorporated into a mathematical optimization model for more accurate predictions concerning feed intake and other production parameters.

AFRIKAANSE OPSOMMING: ‘n Groot hoeveelheid navorsing het al in die ontwikkeling van groeimodelle vir ander enkelmaagdiere gegaan. Hierdie modelle inkorporeer nie net verskeie biologiese- en dierverwante faktore, voerfaktore en die omgewing nie, maar ook die interaksies wat tussen al die genoemde faktore bestaan. Om so ‘n wiskundige optimeringsmodel vir broeivolstruise te ontwikkel, moet al die faktore wat voerinname en produksie van broeivolstruis-behoeftes beinvloed ondersoek word. Daarom is hierdie studie se doel om die moontlike faktore wat 'n invloed het op voerinname en produksie van broeivolstruise te identifiseer en te kwantifiseer. In die eerste studie (Hoofstuk 3), is die effek van verskeie voedingstowwe op voerinname en produksie van broeivolstruise geëvalueer. Geen spesifieke effek van enige een van die getoetste parameters (addisionele vitamiene, minerale, vetsure en aminosure) is sigbaar in die reproduksiesyfers van die broeivolstruise nie. Beduidende verskille is wel gevind in die hoeveelheid voer wat ingeneem is en toon ‘n moontlikheid dat broei volstruise hul voerinname aanpas ten opsigte van hul mineraa behoeftes. Die verskaffing van bykomende vitamiene en minerale tydens die rusperiode kon 'n invloed op die resultate hê. In die tweede studie (Hoofstuk 4) is die effek van die toevoeging van minerale en vitamiene in die rus- en broeiperiode op die produksie van broeivolstruise ondersoek. Die teenwoordigheid van 'n vitamien- en mineraalaanvulling tydens die rusperiode het daartoe gelei dat wyfie-broeivolstruise 31.2% minder gewig verlies ervaar het. Dit het ook gelei tot ‘n 8.1% afname in die aantal dood-in-dop (DIS) eiers tydens die broei seisoen. Wyfie-broeivolstruise het ook 5.3% minder gewig verlies getoon as gevolg van die verskaffing van ‘n vitamien- en mineraalaanvulling tydens die broeiperiode. ‘n Neiging, om groter eiers en kuikens te produseer is wel gevind by wyfie-broeivolstruise wat geen aanvulling ontvang het tydens beide die rus- of broeiperiode nie. Die gevolgtrekking van hierdie studie is dus dat ‘n vitamien- en mineraalaanvulling tydens die rus- sowel as broeiperiode noodsaaklik is. Soja-oliekoek (SOC), wat hoofsaaklik gebruik word as ‘n proteienbron in broeivolstruisdiete, se skaarsheid en onbekostigbaarheid het daartoe gelei dat ‘n alternatiewe proteien bron, naamlik katoensaadoliekoek (CSOC), se geskiktheid ondersoek is in Hoofstuk 5. Katoensaadoliekoek as 'n bron van proteïen het geen wesenlike uitwerking op die meeste van die produksieparameters (totale aantal eiers, DIS eiers, onvrugbare eiers of kuikenproduksie) nie, maar het gelei tot 'n aansienlike afname in die hoeveelheid kuikens wat uitgebroei het. Totdat daar meer navorsingsuitslae beskikbaar is, word daar voorgestel dat produsente die voorkomende benadering volg en nie CSOC gebruik in die voeding van broeivolstruise nie. Vir die ontwikkeling van ‘n simulasiemodel vir broeivolstruise, moet die onmiddelike effek van die voer se energie-inhoud op voerinname, sowel as die langtermyn effek op produksie bepaal word (Hoofstuk 6). Een honderd volstruisbroeipare is in vyf groepe van twintig broeipare elk ingedeel. Elke groep het een van vyf eksperimentele diëte ad libitum ontvang tydens twee opeenvolgende broeiseisoene. Hoewel vorige studies van Brand et al. (2002, 2003) getoon het dat die produksie in die huidige paarseisoen beinvloed kan word deur voeding wat in die vorige paarseisoen ontvang is, is geen sodanige effek op die produksieparameters gemeet nie (totale eierproduksie, DIS eiers, onvrugbare eiers, kuikenproduksie, wyfie-broeivolstruis gewigsverandering of voerinname). Broeivolstruise het ook geen regulering van voerinname getoon weens die energie-inhoud van die voer nie. Literatuur het aan die lig gebring dat die digtheid van die voer (Bulk density) moontlik die voerinname van broeivolstruise kan beinvloed. Weens die gebrek aan verskille in die produksieparameters gemeet, kan moontlike toekomstige studies die effek van lae en hoë vlakke van basale energie verskaf, oor drie of meer agtereenvolgende paarseisoene insluit. Eierproduksie, deur wyfie-broeivolstruise, word beskou as ‘n duursame proses vir die wyfie aangesien sy eiers produseer wat dikwels lei tot gewigsverlies. Derhalwe is die eier-lêpatroon vir broeivolstruise bepaal vir insluiting in die optimeringsmodel (Hoofstuk 7). Resultate van hierdie studie het aangedui dat die ouderdom van die wyfie ‘n rol speel in die hoeveelheid dae tot die eerste eier geproduseer word, sowel as die totale aantal dae waartydens eie produksie plaasvind. Bewyse van die patroon wat beskryf is deur Shanawany (1999) is gevind, maar as gevolg van die hoogs veranderlike eierproduksie en verskeie aantal faktore wat die eierproduksie beinvloed, kon 'n spesifieke eierlê-patroon oor die broeiseisoen nie geïdentifiseer word nie. Hierdie tesis maak 'n betekenisvolle bydrae tot die kwantifisering van die faktore wat die produksieparameters in broeivolstruise beinvloed. Die meeste van die resultate wat verkry is in die studies sal in die wiskundige optimeringsmodel van Gous en Brand (2008) geïnkorporeer word vir meer akkurate voorspellings van voerinname en produksieparameters.

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