Fifteen adenoviruses from cattle, sheep, horses, and llamas were studied by virus neutralization to determine their degree of antigenic similarity. Prototype viruses included bovine adenoviruses species 1-8, ovine adenoviruses species 5 and 6, and equine adenovirus species 1. Unclassified viruses that were compared to the prototype viruses were isolated from different locations within Oregon and were represented by bovine isolate 32CN, ovine isolates 47F and 475N, and llama isolate 7649. Reciprocal virus neutralization tests were performed and the degree of antigenic similarity, i.e., species differentiation was determined by criteria established by the International Committee for the Nomenclature of Viruses. The study showed that many of the adenoviruses, both prototype and unclassified, shared minor antigenic components with each other. Prototype viruses possessed major antigenic differences and, as previously demonstrated by other investigators, should be classified as separate virus species. Bovine adenovirus isolate 32CN was shown to be of the same species as ovine adenovirus isolate 475N, but neither isolate was similar to any of the prototype virus species studied. Ovine adenovirus isolate 47F was shown to be of the same species as ovine adenovirus species 5 strain RTS 42. Llama adenovirus isolate 7649, while sharing minor antigens with different viruses from cattle and sheep, was shown to be a distinct species. This represents the first species of adenovirus from llama. / Graduation date: 1993

The microclimate within naturally-ventilated transport trailers hauling Canadian cattle to slaughter was investigated by recording temperature and relative humidity in one-minute intervals during commercial transport. Conditions on the outside of the trailer (ambient), at the trailer ceiling and at the animal tag-level were monitored. These metrics were used to calculate humidity ratio and temperature humidity index (THI) to further investigate the moisture content of the air and the apparent thermal conditions within the vehicle, respectively. The trailer micro-environment was assessed between trailer compartments and between planes within a given compartment. Five commercial long-haul (940 km) and five commercial short-haul (85 km) warm weather journeys (average daily temperature 24.5°C) were conducted to represent common distances traveled by finished Canadian heifers during summer and early fall. Variations in temperature, THI and humidity ratio were evident within the trailer and the results illustrated the most challenging compartments, in terms of thermal environment, at the front of the trailer and on the top level. Thermal conditions were greater inside the trailer compared to ambient (average 1.97°C for long and short distances combined), greater at the animal-level compared to the trailer ceiling (3.03°C for long and short distances combined) and greater in the center plane compared to the outside walls during long distance journeys. The physiological effect of transport on the cattle was measured through on-going monitoring of vaginal temperature of focal heifers located throughout the trailer. Body temperature recordings showed the ability of the animals under these conditions to dissipate heat acquired through the loading period. Cattle transported long distance however showed a better ability to return to near-baseline body temperature values. Shrink, or body weight loss, was calculated by each compartment of animals for all journeys. Cattle that travelled further lost a greater percentage of body weight (P < 0.001) with values of 4.5% and 1.6% for long and short distances, respectively. Further, cattle located in compartments that had higher temperatures and greater moisture levels recorded in the microclimate data showed correspondingly increased body weight loss (P < 0.05) suggesting that the nose compartment in particular had a greater potential to induce thermal stress.

Neurotensin (NTS) is a tridecapeptide which is widely distributed in the central nervous system and digestive tract. It is highly expressed in neurons of the hypothalamus, a region of the brain known to control feeding behavior. Several studies have shown that intracerebroventricular injection of NTS decreased food intake in rats. NTS was therefore characterized and analyzed for associations with growth and carcass traits in beef cattle.<p>NTS mRNA was successfully isolated from brain, spinal cord, abomasum, rumen wall, small intestine and skin samples. The complete bovine mRNA sequence was obtained from skin, along with partial genomic sequence. Three single nucleotide polymorphisms (SNPs) in the 3 untranslated region (3UTR) and six intronic SNPs were identified. The three SNPs in the 3UTR were not in linkage disequilibrium. Of the three SNPs in the 3UTR, two had minor allele frequencies of 2% and therefore were not analyzed further. The minor allele frequencies for the third SNP (*419G>A) ranged between 0% and 23% for four major beef breeds. The *419G>A SNP was also used to map NTS to bovine chromosome five between markers BM6026 (13 cM, LOD=4.03) and RM103 (4 cM, LOD=3.63).<p>No significant associations between the *419G>A SNP and growth traits were identified. Statistical analysis revealed significant genotype associations for rib eye area (REA), grade fat and moisture in the Canadian Beef Reference Herd (CBRH). These associations were not verified in a second group of purebred yearling bulls. However, significant associations with end of trial fat, %fat and fat deviation were associations for marbling and quality grade. In all cases the AA genotype was associated with increased fat.<p>Although significant associations between carcass measurements and genotype at the *419G>A SNP were present in some populations, none of these associations were found in more than one population. It was therefore concluded that the *419G>A SNP on the bovine NTS gene does not prove to have an economic advantage to the beef cattle industry.

LLH-HOG oat grain (low in ADL and high in EE) was compared to Derby oat, and CDC Dolly barley grain. Twenty-one Suffolk wethers were randomly assigned diets, 100% barley silage or barley silage with 50, 75, or 90% (DM) LLH-HOG oat or CDC Dolly barley. Apparent digestibility of DM, CP, EE, NDF, ADF, and GE were determined. Linear and quadratic regressions were fitted and apparent digestibility at 100% grain was determined. DM apparent digestibility was estimated at 79.1% for CDC Dolly barley and 74.0% for LLH-HOG oat grain. LLH-HOG oat provided 3550 Kcal per kg DE and CDC Dolly barley provided 3582 Kcal per kg DE. A non-lactating Holstein cow with a rumen fistula was used to determine LLH-HOG oat, Derby oat, and CDC Dolly barley grain degradability. Samples were incubated in the rumen for 48, 36, 24, 12, 08, 04, and 00 hour. The in situ degradability of DM, CP, and NDF were determined. An <i>in vitro</i> study was conducted using a Daisy II Incubator for incubations of 48, 30, and 24 hour. The DM ED of CDC Dolly barley (77.0%) was greater than both oat (68.0 and 68.9%). The NDF ED in LLH-HOG oat (26.6%) was higher than that of Derby oat (24.0%). Nine lactating Holsteins were randomly assigned treatments in a triple replicate three x three Latin square. Treatments were 50:50 forage to concentrate (DM basis) TMR with grain sources of CDC Dolly barley, Derby oat, or LLH-HOG oat. Milk production, dietary consumption data, and apparent digestibility were collected. DMI of the different TMR were similar. Milk yield tended (P=0.09) to be highest in LLH-HOG oat fed cows. FCM, MF, and MP yields were not different. MP concentration was lowest in LLH-HOG oat fed cows. Cows fed LLH-HOG oat, compared to Derby oat, trended (P=0.08) towards requiring less DM to produce 100 kg FCM. The TMR DE and apparent digestibility of DM and NDF were higher in cows fed LLH-HOG or CDC Dolly barley compared to Derby oat. LLH-HOG oat had superior nutritional characteristics for dairy cows compared to conventional oat and was equal to barley.

Although most Holstein cattle are either black with white spots or red with white spots, two new coat colour traits called Variant Red (VR) and changeling, have recently been recognized by Holstein Canada. Variant red cattle look the same as red and white Holsteins but VR appears to be inherited as a dominant trait. Changeling cattle are born red and turn black by adulthood. Candidate genes for changeling included melanocortin 1 receptor (MC1R), agouti signalling protein (ASIP), attractin (ATRN), and melatonin receptor 1A (MTNR1A). Candidate genes for variant red included these same genes and β-defensin300 (putative K locus). Polymerase chain reaction restriction fragment length polymorphisms (PCR-RFLP) and sequencing were used to genotype single nucleotide polymorphisms (SNPs), which were recently discovered in our lab, for use in determining co-segregation in appropriate families. Cosegregation analysis excluded MC1R, ASIP, ATRN, or MTNR1A for changeling and VR, assuming single gene inheritance. Microsatellites and SNPs were used to map VR to a region on BTA27 surrounding and including β-defensin300 (LOD = 3.255). Cattle β-defensin300 was characterized from genomic DNA and mRNA from skin and appears to be homologous to canine β-defensin103 which is involved in black/red coat colour differentiation in many dog breeds. Although no mutations were found in the coding sequence, several were found in the 5, putative promoter region. No polymorphisms consistently and exclusively occurred in VR and not in changeling and/or black and white Holstein cattle. Common relatives occurred in the pedigrees of several variant red and changeling cattle. A hypothesis was developed which suggests that a common mutation is required for the occurrence of either phenotype. A dominant mutation in a second gene would be required for VR, potentially a promoter mutation in β-defensin300. Two recessive alleles at a yet unidentified second gene, potentially a promoter mutation in ASIP, would be required for the changeling phenotype to occur.

Four studies were conducted in the Texas Panhandle during the summer of 2007 to evaluate methods for cooling cattle in three phases of production (unweaned calves in hutches, weaned heifers on pasture and lactating cows). Unweaned calves (n = 20) housed in polyethylene hutches, covered with reflective aluminum and bubble film insulation, were compared to calves (n = 18) in similar, un-insulated hutches. Mean thermal heat index (THI) for the trial was 71.9 ± 5.5 (SD). Insulation treatment did not affect body weight gain (P > 0.044). Insulation affected interior hutch temperature, calf body temperature, and respiration rate (P < 0.05), indicating insulation may moderate temperature extremes within the hutch. Weaned heifers (n = 55) on pastures with shade were compared to similar heifers (n = 62) in pastures without shade. Mean THI for the trials was 70.8 ± 6.2 (SD). Shade treatment increased body temperature (P = 0.03) and decreased body weight gain. The effect of shade on foraging behavior was dependant on THI. Shade use by heifers was dependant on THI and wind speed. Heifers utilized shade when THI was above 72, especially when wind speed was low. Feed bunk attendance was compared among pens (n = 3) of lactating cows where the feed bunk was equipped with water sprinklers that sprayed the backs of cows and pens (n = 2) without feed bunk sprinklers. Mean THI for the trial was 70.8 ± 5.7 (SD). Feed bunk sprinklers mediated the affect of elevated THI on decreasing bunk attendance, but overall bunk attendance was not different among treatments. Lactating dairy cows, cooled with water sprinklers and fans three times each day in the holding pen prior to milking, were compared with similar cows cooled in the holding pen by fans only. Mean THI for the trial was 69.9 ± 5.3 (SD). Body temperature, milk yield and somatic cell count were not different among treatments. Sprinkled cows had lower milk fat and total protein than control cows. Sprinkling cows in the holding pen when THI is less than 70 may negatively affect milk production.

The objectives of this study were accomplished with two experiments in growing Bonsmara bulls (N = 68) (experiment 1), and Simmental crossbred calves (N = 132) (experiment 2). Specific objectives for experiment 1 were to characterize residual feed intake (RFI) in growing bulls, and examine relationships between RFI and performance, fertility, temperament and body composition traits. In experiment 2, the objectives were to examine stocker-phase supplementation effects on feedlot feed conversion ratio (FCR) and RFI and to characterize relationships between these feed efficiency traits, and performance and carcass traits in finishing calves. In both experiments, individual feed intakes and BW were measured. Ultrasound technology was used to measure body composition in experiment 1, while actual carcass measurements taken at harvest were used for experiment 2. Experiment 1 demonstrated that temperament affected ADG and DMI, but not FCR or RFI. Residual feed intake was not phenotypically correlated to scrotal circumference or bull fertility traits. Experiments 1 and 2 demonstrated that RFI was independent of ADG and BW, but that there was a tendency (P < 0.10) for RFI to be phenotypically correlated with 12th rib fat thickness (r = 0.20 and 0.22). However, RFI was not correlated with longissimus muscle area in either experiment. Both experiments demonstrated that low RFI (< 0.5 SD below mean RFI) calves consumed significantly (20 and 22%) less feed and had improved (21%) FCR compared to calves with high RFI (> 0.5 SD above mean RFI). Results from experiment 2 suggest that RFI measured while calves are consuming high-grain diets may be less influenced by previous level of stocker supplementation compared to FCR or residual gain efficiency traits. In summary, RFI was found to be phenotypically independent of growth rate and BW, had no effect on bull fertility or temperament traits, and was less impacted by previous plane of nutrition compared to FCR.

Purebred Beefmaster steers (n = 160) from five owners were fed at a commercial feedlot in South Texas beginning in November of 2004; 68 steers possessed pedigree information. Beginning in mid-November, steers were individually weighed and evaluated for ultrasound body composition at 56-d intervals by a certified technician. Feeder calf frame (FRM) and muscle (MUS) scores were assigned at initial ultrasound evaluation. Steers were fed and marketed through a lean-based, branded beef program and were harvested in two groups in May and June of 2005 at a commercial beef plant. Analyses were conducted to investigate the ability to predict carcass traits from the different sources of information available on these cattle. Evaluation of carcass traits were investigated using four sets of independent variables referred to as sources A, B, C, or D and ultrasound scan session (1 – 4). An analysis included initial weight at first scan session (IWT), FRM and MUS as independent variables through GLM procedures. B analyses utilized ultrasound measures of the longissimus area, intramuscular fat, fat thickness, rump fat, and gluteus medius depth along with IWT as independent variables. Multiple regression was performed on each carcass trait using IWT and ultrasound traits at each scan session. Mallow’s CP was used to select a model that best described each carcass trait. C analyses (GLM) utilized variables from A and B analyses combined plus ranch. D analyses (GLM) included variables from C analyses plus sire nested within ranch. Respective R-square values (scan 1 – 4) for marbling score were .02, .04, .05, and .10 using A information, .14, .17, .42, and .54, using B information, .35, .35, .47, and .55 using C information, and .56, .59, .65, and .76 using D information. R-square values ranged from .34 to .86 for carcass weight, .11 to .77 for fat thickness, .06 to .82 for ribeye area, and .10 to .81 for yield grade. Ultrasound data obtained closer to harvest and increasing amount of data related to genetic and management background showed increased R-square values, but may be best utilized in conjunction with one another to predict carcass traits and final carcass value.

Two experiments tested the efficacy of gonadotropin-releasing hormone (GnRH) or estradiol cypionate (ECP) administration in combination with controlled internal drug release (CIDR) inserts on pregnancy rate to fixed-time artificial insemination (FTAI) in beef heifers. In the first experiment, heifers in the two ECP groups received ECP in conjunction with the CIDR insert. The CIDR insert was removed and PGF was administered on either d 7 or 9. Heifers received ECP 24 h after CIDR removal and were inseminated 30 h after ECP. Heifers in the two GnRH groups received GnRH in conjunction with the CIDR insert. Heifers received PGF on either d 6 or 7, and the CIDR insert was removed on d 7. Heifers were inseminated and received GnRH 48 h after CIDR removal. Pregnancy rates to FTAI were higher for heifers treated with GnRH. Pregnancy rate to FTAI was highest for heifers in the GnRH group that received PGF on d 6 and was lowest for the group that received ECP in combination with a 7-d CIDR insert. In the second experiment, heifers received GnRH in conjunction with the CIDR insert. CIDR inserts were removed and PGF was administered on d 7. Heifers were inseminated 60 h later, with one group receiving GnRH at insemination. Pregnancy rate to FTAI was higher for heifers that received GnRH at insemination. The final experiment tested the efficacy of estradiol 17_ (E17) or GnRH in combination with a CIDR insert on pregnancy rate to FTAI in Brahman cows. Either E17 or GnRH was administered in conjunction with the CIDR insert. CIDR inserts were removed on d 7. Cows in the GnRH group received PGF on d 6 and GnRH at insemination which occurred 48 h after CIDR removal. Cows in the E17 group received PGF on d 7, E17 24 h later, and were inseminated 30 h after E17 administration. Pregnancy rate to FTAI was higher for cows treated with E17. These data indicate acceptable pregnancy rates were obtained when the CIDR insert was combined with either GnRH in beef heifers or with E17 in Brahman cows.

The U.S. has a history of producing surplus corn, but the current and projected growth in ethanol production combined with strong feed and export demand is causing an overall increase in corn utilization. Although livestock feeders are projected to remain the largest users of corn, corn utilization can be reduced if ethanol co-products are used to replace a portion of corn in finishing rations. The objective of this study was to determine the economic trade-offs for cattle feeders when facing higher corn prices and increasing supplies of ethanol co-products. A stochastic partial budget model was used to determine the impact on the cost of gain when ethanol co-products are substituted into rations at varying inclusion rates. The model was built for all four major cattle feeding states: Texas, Nebraska, Kansas, and Colorado. Ration scenarios were developed for each state, based on the research results of feedlot nutrition and personal communication with feedlot operators. The various scenarios were simulated to determine the impacts of changing corn prices, corn processing costs, cattle performance, and feeding and transportation costs for Wet Distiller’s Grains with Solubles (WDGS) on the key output variable, cost of gain. The model results indicated when 15 percent WDGS (on a dry matter basis) replaces a portion of corn and protein supplement, the simulated cost of gain is lower than the base ration scenario when the feedlot is located within 200 miles of ethanol production. When feedlots are located more than 200 miles from an ethanol plant, Dried Distiller’s Grains with Solubles (DDGS) can be fed to lower the cost of gain; therefore, ethanol co-products can be fed to help offset potential increases in corn prices. The partial budget model is a useful tool for livestock, corn, and ethanol producers who are attempting to determine the impacts of ethanol expansion on corn price and utilization. Policy makers can also benefit from the model analysis as they face decisions in the future regarding ethanol and farm policy alternatives.