Call number: LD2668 .T4 1986 N44 / Master of Science / Agricultural Economics

Call number: LD2668 .T4 1985 C34 / Master of Science

Department of Animal Science / MSCAGR (Animal Science)

Master of Science / Department of Agricultural Economics / Glynn T. Tonsor / The purpose of this analysis is to examine two aspects of price analysis in the stocker industry in order to better assist producers making purchasing decisions. One analysis looks at forecasting value of gain, while the second looks at drivers of price differentials between calves and yearlings. When analyzing forecasts on value of gain, weekly data was collected to compare a naïve approach and futures market implied basis-adjusted approaches that include one to five years of historical average basis. This allowed for the assessment of five different models for nine scenarios. The conclusions from this were inconsistent with what was hypothesized and the naïve approach was either worse or no better when compared to using the futures market implied basis-adjusted approaches to forecast value of gain. The drawback to this analysis was that it was solely influenced by error on forecasting the selling price and in future work a forecasting horizon will be incorporated on the buying price. In order to analyze the price premiums and discounts between calves and yearlings, a confirmation, update and expansion were completed following monthly models by Marsh (1985). Three elements are considered when predicting price premiums and discounts between two weight classes; cost of gain (proxied by corn price), slaughter price, and seasonality. Estimated models in the confirmation for years 1972 to 1982 and the update for years 1973 to 2013, show that premiums and discounts are influenced by expected changes in corn price and/or slaughter price, but not highly affected by seasonality. However, in the expansion for years 1993 to 2013, corn price, slaughter price, and seasonality were all significant to the models and in higher magnitude when compared to those results in the confirmation and update. Understanding the relationships between all variables in these models allows producers in the cattle-feeding industry to make management decisions based on current marketing conditions and trends.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Six groups each with six Friesian bull calves were used in this investigation and slaughtered at 20 weeks of age. Calves received a low- (LD) or high (HD) degradable protein diet, each with or without rumen inert fat supplementation. Two commercial fat sources were used, Morlae (m) and Golden Flake (gf), included at 2.5% of the diet. A commercial milk replacer (Denkavit) was fed at 4L for 42 days, followed by 2L until weaning at 49 days of age. The starter diets were fed ad lib. from day 14 to 10 weeks of age and finishing diets ad lib. from 11 to 20 weeks of age. There were no significant differences in body mass gain or dry matter intake over the entire 20 week period. The feed conversion ratio (FCR) was improved significantly (P=0.0032) when fat was supplemented to LD, but not to HD diets. The FCR (kg dry matter/ kg gain) ofLD, HD, LDm, HDm, LDgfand HDgfdiets were 3.45,3.44,3.07, 3.81, 3.02 and 3.43, respectively. All 36 calves were used in a digestibility trial, using chromium oxide (Cr203) as a marker, during week 18 of the investigation. Digestibility values (%) for the six diets (LD, HD, LDm, HDm, LDgfand HDgf) were 61.74, 65.91, 75.44, 69.00, 75.54 and 67.15 for dry matter, 61.44, 61.60, 71.33, 68.23, 75.44 and 66.12 for crude protein and 58.56, 66.45, 75.98, 70.92, 78.43 and 70.79 for fat, respectively. The dry matter (P=O.OOOl)and fat (P=O.OOOl) digestibilities were only significantly higher when fat was added to LD diets. The crude protein (CP) digestibilities were significantly higher when fat was added to either the LD (P=0.0001) or the HD (P=0.0488) diets. All the calves were slaughtered at 20 weeks of age and the fatty acid content of the meat (m. longissimus) and subcutaneous fat layer adjacent to the 12th rib as well as the meat colour, was determined. The fatty acid composition of the longissimus muscle was changed by feeding the rumen inert fat sources. The three predominant fatty acids found were palmitic, stearic and oleic acids. The palmitic acid (CI6:0) content of the muscle and diet was 24.44 & 20.47,25.97 & 22.57,31.06 & 33.23, 30.98 & 37.91, 34.94 & 31.77 and 29.71 & 32.88 of the total fat for the LD, HD, LDm, HDm, LDgf and HDgf diets, respectively. The C16:0 content was significantly higher in the muscle of the calves receiving the LD diets supplemented with fat (P=0.0008). There was also a significant interaction between the two fat sources and protein degradability (P=0.0065), but only in the LD diets. The stearic acid (CI8:0) content of the muscle and diet was 14.35 & 5.22, 19.65 & 8.61, 17.29 & 4.68, 22.59 & 5.78, 22.27 & 15.54, and 26.48 & 20.15 of the total fat for the LD, HD, LDm, HDm, LDgfand HDgfdiets, respectively. The C18:0 content was significantly higher in the muscle of calves receiving the HD (P=O.OOOl)compared to LD diets. The stearic acid content was also significantly higher when fat was added to LD (P=0.0042) or HD (P=0.0073) diets. The oleic acid (CI8:1) content of the muscle and diet was 36.06 & 21.51,39.99 & 21.11,32.21 & 23.67, 29.13 & 24.59, 25.23 & 18.68 and 35.93 & 16.02 of the total fat for the LD, HD, LDm, HDm, LDgf and HDgf diets, respectively. The linolenic acid (CI8:3) content of the muscle was significantly higher (P=0.0038) when fat was added to LD diets compared to no fat supplementation (0.87 vs. 0.15). The CIELAB values indicated that LD diets resulted in more pink meat. Mean values ofL* =-32.61, 34.19; a* = 7.08, 7.91 and b* = 3.18 and 4.07 were observed for the LD and HD diets, respectively. Meat from the LD diets had significantly lower L*-(P=0.0252), a*-(P=0.0283) and b*-(P=0.0109) values compared to meat from the HD diets. It was concluded that there was a positive response in CP digestibility when rumen inert fats were supplemented to LD or HD diets, although a greater response was shown in the LD diets. The FCR, dry matter and fat digestibility were only increased when fat was added to the LD and not to the HD diets. Similarly, the fatty acid contents of the longissimus muscle of veal calves can be manipulated with the supplementation of rumen inert fat sources, but only when combined with a low protein degradable diet. The low degradable protein diets also produce a more attractive meat colour for the potential veal consumer. / AFRIKAANSE OPSOMMING: Ses behandelings, lae- (LD) of hoë (HD) degradeerbare diëte, elk met of sonder rumeninerte vetsupplementering, is geëvalueer met ses kalwers in elke groep. Twee kommersiële vetbronne is gebruik, nl. Morlae (m) en Golden Flake (gf) teen 'n 2.5% insluitingspeil. 'n Kommersiële melksurrogaat (Denkavit) is aangebied teen 4L1dag tot 42 dae ouderdom, gevolg deur 2L/dag tot speenouderdom op 49 dae. Aanvangsdiëte is ad lib. aangebied vanaf 14 dae tot 10 weke ouderdom en die groeidiëte ad lib. vanafweek 11 tot 20. Daar was geen betekenisvolle verskille in die totale massatoename of die droëmateriaalinname nie. Die voeromsettingsverhouding is betekenisvol verbeter (P=0.0032) in die behandelings waarin rumeninerte vette by LD diëte ingesluit is, maar nie by die HD diëte nie. Die voeromsettingsverhouding (kg droëmateriaalinname / kg massatoename) van die LD, HD, LDm, HDm, LDgf en HDgf diëte was 3.45, 3.44, 3.07, 3.81, 3.02 en 3.43, onderskeidelik. Al 36 kalwers is in 'n verteringsproef gebruik gedurende week 18 van die proef. Chroomoksied (Cr203) is as merker gebruik. Verteerbaarheidswaardes vir die ses diëte was 61.74, 65.91, 75.44,69.00,75.54 en 67.15 vir droëmateriaal, 61.44, 61.60, 71.33, 68.23, 75.44 en 66.12 vir ruproteïen en 58.56, 66.45, 75.98, 70.92, 78.43 en 70.79 vir vet, onderskeilik. Die droëmateriaal- (P=O.OOOl) en vetverteerbaarheid (P=O.OOOI) was slegs betekenisvol hoër wanneer vet by LD diëte gevoeg is en nie by HD nie. Die ruproteïen (RP) verteerbaarheid Stellenbosch University http://scholar.sun.ac.za VI was betekenisvol hoër (P=0.0002) by LD en HD (P=0.0488) diëte met vet supplementering, teenoor geen vet insluiting. Die kalwers is op 20 weke ouderdom geslag en die vetsuursamestelling van die vleis (m. longissimus) en die subkutane vetlaag teenaan die 12de rib, asook en die vleiskleur, is bepaal. Die vetsuursamestelling van die longissimus spier is deur die supplementering van rumeninerte vet verander. Die drie primêre vetsure wat in die vleis voorgekom het, was palmitiensuur, steariensuur en oleïensuur. Die palmitensuur (CI6:0) inhoud van die spier en diëte was 24.44 & 20.47, 25.97 & 22.57, 31.06 & 33.23, 30.98 & 37.91, 34.94 & 31.77 en 29.71 & 32.88 van die totale vet van die LD, HD, LDm, HDm, LDgf en HDgf diëte, onderskeilik. Die C16:0 was betekinisvol hoër in die spiere van kalwers wat die LD diëte met vet supplementering (P=0.0008) ontvang het. Die steariensuur (CI8:0) inhoud van die spier en diëte was 14.35 & 5.22, 19.65 & 8.61, 17.29 & 4.68, 22.59 & 5.78, 22.27 & 15.54, en 26.48 & 20.15 van die totale vet vir die LD, HD, LDm, HDm, LDgf en HDgf diëte, onderskeidelik. Die C18:0 inhoud was betekinisvol hoër in die spiere van die kalwers wat die HD (P=O.OOOI),teenoor LD diëte ontvang het. Die steariensuur inhoud was ook betekenisvol hoër wanneer vet by LD (P=0.0042) of HD (P=0.0031) diëte gevoeg word. Die oleïensuur (CI8:1) inhoud van die spier en diëte was 36.06 & 21.51, 39.99 & 21.11, 32.21 & 23.67, 29.13 & 24.59, 25.23 & 18.68 en 35.93 & 16.02 van die totale vet vir die LD, HD, LDm, HDm, LDgf en HDgf diëte, onderskeidelik. Die linoleensuur (CI8:3) inhoud van die spier was betekinisvol hoër (P=0.0038) in die LD diëte met vet teenoor LD met geen vet supplementering (0.87 vs. 0.15). Die CIELAB waardes van die LD diëte dui op 'n pienker vleiskleur. Gemiddelde waardes van L* = 32.61 & 34.19, a* = 7.08 & 7.91 en b* = 3.18 & 4.07 is vir die LD en HD diëte, onderskeidelik, waargeneem. Die vleis van die LD diëte het 'n betekenisvol laer L*-(P=0.0252), a*-(P=0.0283) en b*-(P=0.0109) waarde in vergelyking met die HD diëte getoon. Die resultate dui daarop dat daar 'n positiewe respons in die ruproteïenverteerbaarheid by die supplementering van rumeninerte vette by LD en HD diëte voorkom, maar die response op die LD diëte is groter. Die voeromsettingsverhouding, droëmateriaal- en vetverteerbaarheid is egter net bevoordeel in die LD met vet en nie in die HD diëte nie. Die vetsuursamestelling van die longissimus spier in die kalf kan gemanipuleer word met die supplementering van rumeninerte vetbronne, maar slegs wanneer dit gekombineer word met lae degradeerbare proteïen diëte. Die lae degradeerbare proteïen diëte produseer ook die mees aanloklike vleiskleur vir die potensiële kalfsvleisverbruiker.

Sixty-two newborn Holstein-Friesian calves were used to study the role of colostrokinin, serum cortisol, and serum thyroxine in the absorption of maternal immunoglobulin. Calves were removed from their dams prior to suckling and assigned one of four rations: colostrum, whole milk, milk plus colostral immunoglobulin, and milk plus immunoglobulin plus colostrokinin. Calves were fed their assigned ration either at birth or after twelve hours inanition. All calves were fed pooled colostrum at 24 hours postpartum. Blood samples were collected at seventeen times during the first 32 hours postpartum. Calves were born with high cortisol concentrations (88 ng/ml) which decreased (P < .05) within two hours postfeeding. Serum cortisol levels increased (P < .05) between two and three hours after calves ingested a colostral source of immunoglobulin. Time of initial feeding had no effect on the cortisol surge. No such increase was observed in neonates consuming an immunoglobulin-free milk ration. These results demonstrate that the immunoglobulin fraction of colostrum is responsible for initiating an increase in cortisol secretion by the adrenal cortex. Within four hours postpartum, serum thyroxine concentrations increased (P < .05) at least 50% in all treatment groups regardless of whether the calves were fed or fasted. After peaking at 18 μg/dL, the serum thyroxine concentrations fell gradually throughout the duration of the collection period. Colostrokinin exhibited a biphasic effect on serum immunoglobulin concentrations which was dependent on the initial time of feeding. Calves exposed to colostrokinin in 0 hour feedings had serum immunoglobulin G concentrations significantly higher (P < .05) after 16 hours postpartum than animals not fed colostrokinin. Fasted calves, exposed to colostrokinin at 12 hours postpartum, had no increase in serum immunoglobulin G concentrations following a colostrum feeding at 24 hours postpartum. Fasted calves fed a ration not containing colostrokinin exhibited a two-fold increase in serum immunoglobulin G concentrations after the 24 hour colostrum feeding. Colostrokinin did not have an immediate effect on serum immunoglobulin G concentrations, but required an approximate twelve hour period to manifest its regulatory function. The presence or absence of colostrokinin in the experimental rations did not have any effect on the cortisol or thyroxine profiles. The variable serum immunoglobulin G profiles suggest that colostrokinin is involved in the acquisition of passive immunity by the calf, but colostrokinin may have more than one physiological role.

Two experiments were conducted at the University of Kentucky, Eden Shale Farm, Owenton, KY to evaluate the use of MTB-100TM (Alltech, Inc., Nicholasville, KY) to alleviate the symptoms of fescue toxicity when lactating Angus x Beefmaster cows and their calves grazed endophyte-infected KY-31 tall fescue. Experiment 1 provided a carbohydrate based toxin adsorbent, MTB-100TM, ad libitum in a commercial mineral supplement to project a daily consumption rate of 0, 20 or 40 g of MTB-100TM per cow. Cows were weighed, assigned a body condition score (BCS) and hair coat score (HC), rectal temperatures were recorded and fecal grab samples were taken for ergovaline (EV) and lysergic acid (LA) analysis every 35 days for three grazing seasons (May to September). Calves were also weighed and assigned a HC score. Although MTB-100TM did not improve cow or calf performance, cows older than 4 years and those with greater Beefmaster breeding exhibited a higher tolerance to fescue toxicity than 2 and 3-yr-olds and cows with greater Angus breeding. Experiment 2 was conducted to evaluate the response of lactating beef cows and their calves to strategic supplementation with MTB-100TM. MTB-100TM was mixed with a complete mineral so daily intake was projected to be 0 or 20 g/cow. The experimental period extended from May 5 to October 2 and was divided into 3 strategic periods: P1 = May 5 to July 5; P2 = July 5 to August 31; P3 = August 31 to October 2. Treatments were either 0 or 20 g•cow-1•d-1 MTB-100TM within a period (Treatment 1 = 0, 0, 0; Treatment 2 = 20, 0, 20; Treatment 3 = 0, 20, 0; Treatment 4 = 20, 20, 0; and Treatment 5 = 20, 20, 20). Cow and calf performance was measured the same as Exp. 1, but every 21 days. Supplementation early in the grazing season tended to improve cow weight gain and body condition; however, there was no effect on calf performance. Fecal output of EV and LA did not increase in either experiment with supplementation. In conclusion, strategically invoked MTB-100TM consumption can increase performance of cows grazing endophyte-infected tall fescue forage.

Master of Science / Department of Animal Science and Industry / L.N. Edwards-Callaway / This thesis includes two studies that assessed pain responses to husbandry procedures in order develop mitigation tools. The objective of the first trial was to identify method-related differences in behavioral pain responses in calves of two ages (6 week and 6 months) subjected to castration: surgical cut (CP; n=18), surgical cut and emasculator (CC; n=20), rubber banding (BAND; n=18), or control manipulation of the scrotum (CONT; n=20). Behavior was evaluated pre- and post-castration to record foot stamps, tail flicks, kicks, elimination, in addition to standing and lying post-castration. For 6 week calves, the probability of kicking and eliminations was greater for surgical castrates and all castrated animals, respectively. The probability of kicking was greatest for all 6 month castrates while BAND and CONT had greater probability of elimination. Both age groups increased standing post-castration. Lying decreased in 6 week calves but was unchanged for 6 month calves. Six week calves displayed more tail flicks and tended to display less foot stamps than 6 month calves. Six week calves showed a decrease in tail flicks and foot stamps in response to castration while 6 month calves showed an increase in both behaviors. CP and CC, but not BAND, resulted in less tail flicks than CONT post castration. The second trial compared the effects of preemptive analgesics administered to calves subjected to dehorning with local anesthesia. Six month Holstein steers were randomly assigned to receive one of the following treatments (n= 8/group): meloxicam (1 mg/kg PO), gabapentin (15mg/kg PO), meloxicam (1 mg/kg) and gabapentin (15 mg/kg) PO, flunixin (2.2 mg/kg IV), or a placebo. Drug, cortisol, ex-vivo prostaglandin, haptoglobin, and substance P concentrations, ocular thermography, algometry, and average daily gain were evaluated. Analgesic-treated calves had lower plasma SP concentrations and improved ADG compared with controls. Flunixin calves had reduced cortisol and ex-vivo prostaglandin concentrations for 24h compared to controls. Meloxicam treated calves showed an increase in MNT at two horn bud sites compared with the other treatments. Overall, the results provide validation of responses to noxious stimuli that can be used to develop pain alleviation for livestock.

O presente trabalho teve como objetivo avaliar a influência da cesariana eletiva no eritrograma de bezerros neonatos da raça Nelore durante os primeiros trinta dias de vida. Os neonatos foram alocados em 3 grupos 8 bezerros obtidos por parto espontâneo (PE), 8 bezerros nascidos por cesariana, sem indução do parto (CSI) e 8 bezerros nascidos por cesariana, com indução do parto (CCI) pelo uso de 25 mg de Dexametasona, 24 horas antes do procedimento cirúrgico, pela via intramuscular. Os nascimentos ocorreram entre 282 e 292 dias de gestação. As amostras de sangue para a determinação do quadro eritrocitário foram colhidas por punção da veia jugular externa, utilizando-se Sistema Vacutainer&reg;. A determinação do eritrograma foi realizada no contador automatizado BC-2800 Vet Mindray&reg;. Os resultados obtidos evidenciam que a cesariana eletiva não influenciou o número de hemácias, das taxas de hemoglobina e nos valores do volume globular a crase sanguínea de bezerros na primeira semana de vida. Na primeira semana de vida observou-se, independentemente do grupo experimental uma diminuição no número de hemácias, das taxas de hemoglobina e nos valores do volume globular. Até os 5 dias de vida, os valores de Volume Corpuscular Médio (VCM) e de Hemoglobina Corpuscular Média (HCM) dos bezerros nascidos de partos espontâneos por via vaginal são estatisticamente menores do que os obtidos em bezerros nascidos de cesariana eletiva. A partir de 10 dias de vida observou-se, nos animais obtidos de parto espontâneo, uma rápida recuperação nos valores de hemácias, hemoglobina e volume globular, enquanto nos animais nascidos por cesariana (induzida e não induzida) não ocorria essa recuperação nas taxas de hemoglobina e nos valores do volume globular. Nos bezerros obtidos por cesariana observou-se que no período entre 10 e 30 dias de vida o Volume Corpuscular Médio (VCM) e a Hemoglobina Corpuscular Média (HCM) diminuíram, passando a apresentarem microcitose e hipocromia quando comparados com bezerros obtidos por parto espontâneo. Entre todos os grupos, os animais nascidos por cesariana sem indução apresentaram os valores com menor magnitude do início ao fim do período experimental. Os animais nascidos a termo demonstram uma capacidade de recuperação fisiológica mais apurada que dos animais nascidos por cesariana. / This study aimed to evaluate the influence of elective cesarean section in erythrogram of newborn calves of the Nellore breed for the first thirty days of life. Neonates were divided into 3 groups 8 calves obtained by spontaneous birth (PE), 8 calves born by caesarean section without labor induction (CSI) and 8 calves born by cesarean section with induction of labor (CCI) by the use of 25 mg of dexamethasone 24 hours before the surgical procedure, by the intra-muscular). Births occurred between 282 and 292 days of gestation. Blood samples for determining the erythrocyte frame were collected by puncture of the external jugular vein using Vacutainer &trade; System. The determination of erythrocyte was performed in the automated counter BC-2800 Vet Mindray&reg;. The results show that elective caesarean section did no affect the number of red blood cells, hemoglobin rates and values of the globular volume in the first week of life of calves. At this first week of life was observed, regardless of the experimental group a decrease in the number of red blood cells, hemoglobin rates and values of the globular volume. Until 5 days of age, the mean corpuscular volume values (MCV) and Mean Corpuscular Hemoglobin (MCH) of calves born from spontaneous vaginal deliveries are statistically lower than those obtained in calves born from elective cesarean section. From 10 days of life was observed in animals obtained by from spontaneous delivery, a quick recovery in the values of erythrocytes, hemoglobin and packed cell volume, whereas in animals born via caesarean section (induced and uninduced) did not occur such recovery in the rates of hemoglobin and packed cell volume values. In calves obtained by Caesarean section it was observed that in the period between 10 and 30 days of life Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin (MCH) decreased, submitting a microcytic hypochromic when compared with calves obtained by spontaneous delivery. Among all groups, animals born by caesarean section without induction showed the values with lower magnitude from beginning to end of the trial period. Animals born at term show a more accurate physiological recovery capability in comparingson with animals born by Caesarean section.