Six Angus steers were used in a series of three metabolism trials to study the effect of energy concentration on nitrogen metabolism and digestibility. The experimental design consisted of two randomly selected 3 x 3 Latin squares. Three fattening rations were ted which contained 1133, 1164 and 1222 kcal. digestible energy per lb. feed and 12.18, 12.51 and 12.29% crude protein, respectively. The rations were composed of 10% grass hay, shelled corn, corn cobs and cottonseed meal. An attempt was made to equalize calcium and phosphorus contents. Vitamins A and D were added at the rate or 30,000 I.U. and 3750 I.U. per steer per day, respectively. Energy concentration was varied by changing the proportions of shelled corn and corn cobs. Digestible and metabolizable energy and TDN were all significantly increased with each increase in energy concentration. Digestible energy concentration of feed had no significant effect on nitrogen retention. Biological value waa higher for the medium energy ration than for the low or high energy rations. The quadratic effect was significant (P < .05). The apparent digestibilities of crude protein and ether extract were not influenced by energy concentration. Digestibility of' dry matter, organic matter and NPE significantly increased and digestibility of crude fiber significantly decreased with each increase in energy concentration. / Master of Science

Eighty-six crossbred (Duroc x Yorkshire) gilts were used in two trials (50 gilts in Trial 1 and 36 gilts in Trial 2) for an assessment of the effect of supplemental dietary fat during early gestation on fetal survival, fetal development, and fatty acid concentration in gilt plasma and fetal head and body. Three diets contained 4% (w/w) added fat either as coconut, soybean, or fish (menhaden) oils. A fourth diet was used as a control. On d 37 to 45 postbreeding, gilts were slaughtered and numerous fetal and ovarian measurements made. Two sets of four randomly selected fetuses per gilt from Trial 1 were prepared. Blood samples from each gilt were obtained on the day of slaughter for determination of the plasma fatty acid profile. Across both trials, percentage fetal survival did not differ according to treatment, but in Trial 2 fetal survival was higher (P < .06) for gilts fed fish oil, compared with the controls. The fatty acid profile of plasma of gilts and the conceptus tissues were similar; both were influenced by the fatty acid concentration of the diets. The ratio of n-3/n-6 fatty acids was higher in conceptus tissue than in maternal plasma and the ratio was higher (P < .05) for the fish oil diet compared with the other diets. The relatively high concentration of omega-3 fatty acids in fetal tissues supports the hypothesis that omega-3 fatty acids play a role in the development of the pig conceptus and contributes to improve fetal survival. However, the high percentage fetal survival observed in all the treatments may have masked benefits of supplemental oil. / Master of Science

<p dir="ltr">Boars in the swine industry are one of the select animals subject to limit feeding. Limit feeding boars occurs once boars are selected to enter the boar stud. Before selection boars are <i>ad libitum</i> fed like a nursery or grow finishing pig. Research involving boar nutrition and the impact it has on growth, development, and semen characteristics are limited compared to the rest of the swine industry. The objective of these studies conducted at Purdue University were to determine how varying nutritional feeding strategies impact semen quality and quantity as well as growth and development of artificial insemination boars.</p><p dir="ltr">Feeding fiber is a commonly used strategy in gestating sow nutrition to mitigate some of the negative side effects of limit feeding animals. A variety of fiber sources are available to the swine industry, however most of the common sources used are wheat bran, alfalfa meal, sugar beet pulp, and soybean hulls. Soyhulls are one of the more easily accessible sources of fiber in Indiana and the Midwest U.S. due to large amounts of soybean production and processing which will continue to grow with bi-energy demands. Boars fed the fiber diet (14.3% soyhulls) had increased bodyweight and body condition changes over the twelve-week period. Additionally, fiber inclusion in the diet had no impact on semen characteristics but semen was impacted by the age and breed of the boar. Salivary cortisol levels were reduced in boars fed fiber as well as some changes in behavior were observed.</p><p dir="ltr">The addition of fiber had impacts on growth and development but no impacts on semen. Since boars are limit-fed for so long from selection after the grow-finish period until they are culled this drew up the question if feeding boars different levels after selection (1.8 kg/d or 2.7 kg/d) impacted trainability, first time semen collection characteristics, growth and development of young boars. No differences were observed for feeding level impacting trainability with 92% of all boars regardless of treatment being successfully trained. Semen volume was increased in boars fed 2.72 kg/d by approximately 50% but no other semen characteristics were impacted. Boars fed 2.72 kg/d also had increased bodyweight and body condition score measures.</p><p dir="ltr">The boars subject to the training study unknowingly arrived at the farm naturally infected with porcine circovirus three (PCV3). Research has been conducted on the ability of viruses (PRRSv, PEDv) to be detected and transmitted through semen. Porcine circovirus three is a relatively new variant of circovirus so the opportunity to evaluate the question of if this virus was able to be detected in seminal plasma and the impacts it has on semen characteristics was presented. Serum and semen samples were collected for polymerase chain reaction analysis of detection of PCV3 conducted at Purdue Animal Disease Diagnostic Laboratory. Porcine circovirus three was able to be detected in the serum of positive boars however no positive detection occurred for seminal plasma samples. Morphological abnormalities such as distal midpiece reflex, distal droplets, and head and tail differed between infected and non-infected boars. Young boars sero-positive for PCV3 had decreased total sperm, total normal sperm motility, and head and tail abnormalities but had decreased distal midpiece reflex abnormalities when compared to PCV3 negative young boars. Young boars were also able to maintain the virus for 98+ days, while some old boars were able to clear the virus withing 14 weeks of becoming positive.</p><p dir="ltr">The next chapter evaluated maintenance energy equation listed in the swine NRC 2012 and if it was still accurate for sexually active boars and if weight management through the use of this equation impacted boar performance. Boars were subject to three treatments (150%, 100%, 80%) of maintenance energy for the first nine-week period and 150% and 80% diets were switched for second nine-week period while 100% stayed the same the entire time in a cross-over design. Semen, bodyweight, and body condition parameters were analyzed throughout the two nine-week periods. Boars fed 80% of maintenance had the largest reduction in semen parameters compared to 150% and 100% maintenance fed boars. Additionally, switching 80% feed intake boars to 150% maintenance feed intake, boars were able to recover some of the negative impacts, however they were not able to fully recover in the second nine-week period. Boars fed 100% and 80% maintenance energy lost weight regardless of age. The loss of body weight of the 100% maintenance fed boars indicates the swine NRC 2012 equation is underestimating the modern AI boar maintenance needs. Old boars were able to handle changes in weight and body condition better than young boars as there was reduced variation in serum metabolites analyzed with old boars compared to young boars.</p><p dir="ltr">The last chapter of this thesis focused on a big data project from commercial sow farms. The objective of this study was to determine if breeding gilts at first signs of estrus or after has an impact on sow performance and economic value to parity three. A regression model was developed from on farm data to determine the difference in total born piglets to parity 3 between gilts bred on their first estrus or after. Gilts bred on their first estrus had six fewer total piglets to parity three compared to gilts who were bred after the first estrus. Also, gilts bred after their first estrus had a larger percentage of sows being profitable compared to gilts bred on first estrus. This model data was compared to actual data for comparison between the two. The model with the limited variables inputted and compared to the actual data was fairly accurate with economic profitability and with more refinement the accuracy can be increased.</p><p dir="ltr">Overall, nutrition of the boar needs to be an area of interest in the swine industry to continue improving efficiency of production. Feeding fiber to boars has minimal impact on semen characteristics but can be used to reduce stress in boars that are limit-fed for weight and body condition management. Limit feeding boars beginning at selection reduces growth and development and had negative impacts on first time semen collection volume. Porcine circovirus 3 was not found in the seminal plasma of naturally infected boars when serum analysis was positive. Boars fed below maintenance levels listed in the swine NRC 2012 have negative impacts on semen, bodyweight, and body condition parameters. Once diets were changed boars were able to recover from the feed restriction but not meet baseline measures prior to feed restriction. Young boars are more sensitive to feeding changes than old boars, this could be due to the young animal still growing while the older animal is closer to mature size. Big data projects can aid producers in making production changes decisions to estimate the economic impact it can have to an individual farm or the entire production system.</p>

The purpose of this investigation was to study the influence of the ration of the cow upon the vitamin C content of milk. The determinations were made by the biological assay method and by the chemical titration method. The cows were given four kinds of rations. Similar determinations have been made by other workers. A brief resume of their technique and conclusions follows: From the results of this investigation, it is concluded: 1. That the ascorbic acid content of milk decreases as the stage of lactation increases. 2. That the ascorbic acid of the milk of individual cows varies within the breed. 3. That the age of the cow does not influence the vitamin C content of the milk. 4. That the rate of gain of the assay animals over a period of 74 days was independent of the ascorbic acid content. 5. That the vitamin C content seems to be independent of the ration of the cow. 6. That the “spring milk” carried some factor which influenced a greater gain of weight than other “winter” milk rations. / Master of Science

Master of Science

Mammary cells from lactating rats and dairy cows were cultured in Eagle's minimal essential medium (MEM) with added amino acids. Changes in free intracellular amino acid pools and milk protein synthesis in response to amino acid additions to the medium were measured. Increases in free intracellular amino acid pools are associated with increased protein synthesis and the rate of their change in response to extracellular amino acids would partially reflect the cell's amino acid requirement. The intracellular pools from medium amino acids (except methionine, tryptophan and glutamine) increased with extracellular amino acids but at their own characteristic rate. The ratio of medium amino acids to nonmedium amino acids inside the mammary cell increased with the concentration of amino acids in the medium. Methionine and tryptophan did not have measurable pools in the rat mammary cell and only very small pools in the bovine mammary cell which did not increase with extracellular amino acids. Culturing rat mammary cells with labeled methionine showed only 42% of the intracellular radioactivity was still associated with labeled methionine indicating significant conversion of this amino acid after it entered the cell. A small linear increase in intracellular cystine was observed with elevated cystine in the medium. The responses in cystine, tryptophan and methionine intracellular pools to extracellular amino acids suggest the concentration of these amino acids in the medium are insufficient to meet the bovine mammary cells requirement. Increasing the concentration of amino acids in MEM 1-, 3-, 5- and 7 fold significantly (P < .05) increased β-casein and to a lesser degree β-lactoglobulin synthesis by bovine mammary cells in culture. Individually increasing each of the 13 amino acids in MEM 3-fold showed cystine followed by threonine and then methionine significantly (P < .05) increased the combined synthesis of β-casein and β-lactoglobulin. The correlation between intracellular pool size change and the response in milk protein synthesis to increased individual amino acids was -.51 which was not significant at the .05 level. / Ph. D.

The effects of three fertilization rates of N (0, 112 and 224 kg/ha) as ammonium nitrate and S (0, 34, and 67 kg/ha) as calcium sulphate on yield, chemical composition, digestibility and palatability of orchardgrass (Dactylis glomerata L.) , were studied in a field experiment. Treatments were applied in a randomized block design with a 3x3 factorial arrangement of treatments with four replications. Hay was harvested on 18 Aug. 1982 and fed to sheep in metabolism trials. One half of the initial amount of fertilizer was reapplied and forage was stockpiled. Stockpiled growth was ensiled on 6 Nov. 1982 and was fed to sheep in palatability trials. Fertilizer was reapplied at the initial rates on 27 Apr. 1983 and yield and mineral concentrations were determined on 6 June 1983. Dry matter yield increased in response to N (P<0.01). Nitrogen fertilization decreased NDF (P<0.05) ADF, cellulose (P<0.01) and total S (P<0.01) and increased nitrate-N (P<0.01) in hay and stockpiled growth. In stockpiled growth S increased ADF ( P<0.05) and cellulose quadratically ( P<0.001) at the 34 kg/ha rate. Sulphur increased ( P<0.05) No₃-N in hay but decreased (P<0.05) it in stockpiled growth. The N:S ratio was increased (P<0.01) by N fertilization and decreased (P<0.05) by S fertilization. Nitrogen and S had a quadratic effect (P<0.0001) on lactic acid and water-soluble carbohydrates in silage. Digestibility or palatability of silage was not influenced by N or S. / Master of Science

The effects of red clover (Trifolium pratense, L.), three levels of N (0, 224 and 448 kg•ha⁻1•yr⁻1, as a split application) and two levels of S (0 and 34 kg•ha⁻1•yr ) on the chemical composition and dry matter digestibility of an orchardgrass (Dactylis glomerata, L.) sward were studied. The treatments were replicated three times in a randomized block design with a split-plot arrangement of treatments. Crude protein content, in vitro dry matter digestibility and dry matter yield were increased (P<. 01) with increasing levels of N. Increasing levels of N decreased (P<.05) S content of orchardgrass. The inclusion of red clover did not have any significant effect on the components analyzed, probably due to a low proportion of red clover (approximately 8%) in the mixed sward. Application of S increased ( P<.05) the S content of orchardgrass and decreased N-to-S ratio at all levels of N application. Application of S increased (P<.05) the crude protein and in vitro dry matter digestibility, whereas neutral detergent fiber, lignin and hemicellulose were decreased (P<. 05). Nitrogen fertilization had a quadratic effect (P<.05) on in vivo digestibility of dry matter, acid detergent fiber and hemicellulose and a linear effect (P<.001) on apparent digestibility of crude protein. Inclusion of red clover increased (P<.01) in vivo digestibility of dry matter and hemicellulose, and decreased (P<.01) digestibility of acid detergent fiber and lignin. Application of S had no direct effect on in vivo digestibility of orchardgrass. A linear interaction (P<.01) between N and S was observed for dry matter and crude protein digestibility. Rumen fluid ammonia-N was increased (P<.05) and butyric acid concentration was decreased (P<.05) linearly by N fertilization. / Master of Science

The bioessential trace metals (e.g. zinc, copper and iron) are primarily excreted via the gastrointestinal trace in normal man and animals. Although urinary losses of these trace metals are usually minimal, they have been reported to be markedly elevated during periods of physiological and pathological stress. The possibility that the decreased plasma insulin to glucagon ratio during episodes of stress is responsible for increased urinary trace metal excretion was examined in normal and streptozotocin-diabetic rats. Induction of the diabetic condition resulted in a rapid and persistent increase in the quantities of zinc, copper and iron lost in the urine daily. Diabetic rats excreted 3.4, 5.0, and 4.9-fold more zinc, copper and iron, respectively, at 14 days after injection with the diabetogenic drug than the controls. Insulin treatment of diabetic rats significantly reduced the daily urinary losses of these micronutrients, indicating that altered hormonal balance was the primary cause for elevated urinary excretion. Enhanced urinary losses of these metals were not associated with decreased concentrations of zinc, copper and iron in plasma, liver and kidney. Various processes, including the filterability of the metal, glomerular filtration rate, renal tubular reabsorption and transtubular secretion have been reported to influence urinary excretion of trace metals. Initial studies have been conducted to assess the influence of altered endocrine status on the characteristics of zinc binding and transport by renal brush border membrane vesicles (BBMV) in vitro. The accumulation of zinc by BBMV was found to be temperature dependent. No apparent differences in the binding and intravesicular accumulation of zinc by brush border membrane vesicles prepared from normal and STZ-diabetic rats were observed. Likewise, the efflux of zinc from BBMV prepared from control and diabetic renal cortex was similar. These results indicated that the potential for zinc reabsorption is not altered in the diabetic rats. In vivo studies are required to further assess the characteristics of zinc reabsorption in the native milieu. / M.S.

Six lactating Holstein cows fitted with rumen cannulae and T-type cannulae in the proximal duodenum were used to measure digesta and nitrogen compounds flow to the small intestine during early and midlactation. Fish meal and soybean meal provided 54 and 56% of the protein in the diets composed of corn grain, corn silage and orchardgrass hay, and which contained 15.4 and 15.5% crude protein and 20.9 and 20.5 acid detergent fiber. Spot samples of digesta were collected from the rumen, duodenum and rectum over a period of 72 hours. Co-EDTA and ytterbium were used as liquid and particulate digesta markers to estimate flow and digestibility of nutrients. Cytosine was used as microbial marker. True organic matter digestibility in the stomachs was 48.4, 49.8, 44.9, and 53.2% for fish meal and soybean meal diets and early and midlactation respectively. Protein degradability in the stomachs were 47.2, 65.8, 56.7, and 56.2% for fish meal and soybean meal diets and early and midlactation respectively. Amino acids intake was greater for soybean meal diet but total amino acids reaching the the duodenum were similar for both diets. Valine, methionine, lysine and histidine were less degraded for fish meal but were extensively degraded in soybean meal diet. Least degraded for both diets were glycine, valine, serine, proline and histidine. The advantage of greater quantity of protein escaping ruminal degradation with fish meal supplementation was counterbalanced by less microbial synthesis in the rumen partly explaining the similar response obtained with diets especially in early lactation. / Ph. D.