South Dakota Agricultural Experiment Station

Abstract The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable consequences for many species. Many small isolated populations are going extinct unnecessarily. In many cases, such populations can be genetically rescued by gene flow into them from another population within the species, but this is very rarely done. This novel and authoritative book addresses the issues involved in genetic management of fragmented animal and plant populations, including inbreeding depression, loss of genetic diversity and elevated extinction risk in small isolated populations, augmentation of gene flow, genetic rescue, causes of outbreeding depression and predicting its occurrence, desirability and implementation of genetic translocations to cope with climate change, and defining and diagnosing species for conservation purposes.

Switchgrass ( Panicum virgatum L.) has potential as a lignocellulosic feedstock for biofuel production. However, switchgrass yields need to be increased to make dedicated biomass feedstock economically competitive with conventional crops. Objectives of this study were to determine the importance of tiller density, number of phytomers per tiller, and mass per phytomer as: (i) determinants of biomass yield in swards of switchgrass in the northern Great Plains, and (ii) potential indirect criteria for selection for biomass. Swards of ‘Cave‐In‐Rock’, ‘Nebraska 28’, and ‘Sunburst’ were sampled from June through November during 2005 and 2006. Partial regression coefficients were greater than 0.0 for 93, 87, and 44% of the samples for tiller density, mass per phytomer, and number of phytomers per tiller, respectively. Path coefficient analysis indicated that tiller density and mass per phytomer had consistently large positive direct effects on biomass yield; whereas, number of phytomers per tiller had smaller and less consistent, albeit positive, direct effects on biomass yield. All three of the yield components have potential as indirect selection criteria for improving biomass in switchgrass. However, progress for biomass production in swards from selection for any of the yield components will depend on heritabilities of the yield components and genetic correlations between the components and biomass.

Eighty beef ribs representing four maturity levels, (A, B, C and D) and two marbling levels (slight and moderate) were used in this study. Neither maturity, marbling, nor core location had a significant effect on tenderness as determined by the Warner-Bratzler shear. Steaks from the longissimus dorsi of the more mature carcasses were generally considered less tender than those from less mature carcasses by a taste panel. The taste panel could detect no differences in tenderness due to marbling or sample location. The flavor of the steaks from the less mature carcasses was generally preferred by the panel. Steaks containing a moderate amount of marbling were significantly more juicy than those containing a slight amount. Muscle fiber diameters were significantly (P<.01) larger in the moderate marbling group than in the slight group. A trend toward larger fiber diameters was noted for the muscle fibers from the more mature carcasses. The A maturity protein percents were significantly lower than those of the B, C and D groups. The moderate marbling level had significantly (P<.01) more fat and less moisture than the slight level. The slight level had significantly more protein. Shear and taste tests were significantly correlated. Fiber diameter was not significantly correlated with tenderness.

Journal Article COLCHICINE INDUCED VARIANTS IN SORGHUM Get access C. J. FRANZKE, C. J. FRANZKE Associate Agronomists, South Dakota Agricultural Experiment Station Search for other works by this author on: Oxford Academic PubMed Google Scholar J. G. ROSS J. G. ROSS Associate Agronomists, South Dakota Agricultural Experiment Station Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Heredity, Volume 43, Issue 3, May 1952, Pages 107–115, https://doi.org/10.1093/oxfordjournals.jhered.a106280 Published: 01 May 1952 Article history Received: 04 February 1952 Published: 01 May 1952

Summary These experiments were conducted to determine the possibility of dilating-the cervix to facilitate the ease of collecting ova. The administration of relaxin in conjunction with an estrogen served to relax the cervical muscles. Estrogen alone as judged by the pilot cow gave no cervical relaxation. The minimum dosage of relaxin which gave cervical relaxation was 250 G.P.U.; the optimum, about 1,500 G.P.U. A suitable mechanical instrument was designed for dilating the cervix. However, the instrument must be used with the aid of relaxin when used 5 days post estrus. Histological studies of biopsies from the cervix and uterus indicated no signs of trauma from either the relaxin or the instrument.

FOR many years, residents of certain localities in South Dakota have complained that: (1) It was impossible to obtain satisfactory hatching results in chicks either by natural or artificial incubation. (2) The down on those chicks which did hatch appeared greasy, and never became fluffy. (3) Where higher hatchability was obtained, a high mortality occurred. REVIEW Stockard (1920-21) in his studies on the structural and developmental rate states: “For the past ten years I have claimed that all types of monsters not of hereditary origin are to be interpreted simply as developmental arrests.” He also states: “The lengths of time between fertilization and the first cleavage and the rates at which the early cleavage follow one another may differ decidedly among the eggs of even closely related forms. These differences in developmental rate are probably fundamentally connected with differences in chemical structure of the egg substances, and in particular with . . .

Thirty weanling Duroc gilts were used to study the effect of selenium on swine reproduction and the value of arsanilic acid as a selenium poisoning preventive. Ten p.p.m. of selenite selenium lowered the conception rate and increased the number of services required per conception. Sows fed this ration farrowed a higher percentage of dead pigs and their pigs were smaller and weaker at birth. Fewer pigs were weaned and the 56-day weights of these pigs were significantly reduced. Arsanilic acid in the selenium ration resulted in an improvement in percentage of pigs farrowed alive but did not improve the birth weights or average number of pigs weaned per litter. The greatest advantage of arsanilic acid appeared to be in increasing the weight of pigs at 56 days.

Yearling steers were fed a high-grain ration composed of 80% ground shelled corn and 20% alfalfa hay for 153 or 160 days. Feedlot performance was not improved by increasing the protein content of the basal ration from 10.6 to 11.8%; or by supplementing the rations with about 12,000 I.U. of vitamin A palmitate per head daily. Plasma vitamin A declined from initial values of about 30 mcg. per 100 ml. to 16–18 mcg. per 100 ml. in cattle not supplemented with vitamin A, but to a lesser extent when about 12,000 I.U. of vitamin A were fed daily. Liver reserves of vitamin A were low, being about 1 mcg. per gm. in unsupplemented steers and about 2 mcg. per gm. in steers receiving the additional vitamin A. Initial reserves were not determined, but some indication of gradual depletion is given by the decrease in plasma vitamin A. Dietary carotene (av. of about 42 mg. daily) and body reserves of vitamin A appeared to be meeting the vitamin A needs for growth and prevention of deficiency symptoms under the conditions of this experiment. Adding 1% sodium nitrate to the ration reduced performance, but vitamin A and carotene in the plasma or liver were apparently not affected. Feeding additional vitamin A did not reduce this effect. Clinical symptoms of nitrate toxicity were not evident in any of the steers.

LARGE quantities of sodium chloride, sodium sulfate, and magnesium sulfate render so-called saline waters unsuitable for livestock and poultry consumption. Although sodium chloride is an essential ingredient in the poultry diet, relatively small amounts are required. Selye (1943) reported excessive intakes of sodium chloride via feed or water to cause sudden mortality. He and Peterson (1943) reported 2% sodium chloride in solution to be highly toxic, whereas 2% in feed resulted only in wet litter production. As little as 0.5% salt in solution was reported toxic by Selye (1943). These findings were supported by Field and Eveans (1946) as well as by Kare and Biely (1948). The latter workers found that chicks could tolerate approximately 4% sodium chloride in feed before showing toxic effects, whereas Barlow et al. (1948) reported 3% to be toxic. Equal toxicities were reported by Kare and Biely (1948) for 0.3% and 0.9% salt in…

Experiments were conducted to determine the effects of drinking water containing added sodium nitrate or nitrite on growing-finishing pigs, gilts from weaning through two farrowing seasons and lambs during a growing-fattening period. Levels of sodium nitrate providing up to 300 ppm NO3-N in the drinking water had no adverse effect on weight gain, general thriftiness, or breeding and reproductive performance in swine. Adding sodium nitrite to drinking water to provide up to 100 ppm NO2-N for swine gave measurable but small increases in methemoglobin at the higher levels of nitrite without obvious detrimental effect on performance or liver vitamin A values determined after 105 days on treatment. In sheep 1000 ppm NO3-N in the drinking water gave a peak methemoglobin level amounting to 16% of total hemoglobin. Average methemoglobin levels of lambs receiving 667 or 333 ppm NO3-N never exceeded 5.3% of total hemoglobin during the 84-day trial. None of the nitrate treatments adversely affected performance of the lambs. No evidence was obtained to indicate that consumption of water containing 300 ppm or less of NO3-N was detrimental to swine or sheep.

Steers were graced on a highly seleniferous range for two years, starting as yearlings. The steers allowed slightly less than normal range per animal made the poorest gain but there was no marked advantage in allowing excess range. Steers fed 25 p.p.m. of arsenic in the salt made the best gains and sold at a slightly better price than the others. Furthermore, the incidence of symptoms of selenium poisoning was reduced by this treatment. The selenium content of organs and tissues was determined on samples taken at the time of slaughter.

A NUMBER of investigators (Gerry et al., 1947; Grau and Zweigart, 1953; Miller and Joukovsky, 1953; and others) have studied the availability of the phosphorus supplied by various supplements to chick diets in which common feed ingredients were used. Gillis and associates (1948 (1954) made use of both practical diets and purified diets to evaluate the phosphorus supplements more critically than had been done previously. The results of these investigations have shown steamed bone meal, dicalcium phosphates, defluorinated phosphates and certain other phosphates to be satisfactory as phosphorus supplements to chick diets. Since availability studies of this nature using poults and poult starting diets have not been reported, the following experiments were performed. Day-old Beltsville Small White (BSW) poults from the college breeding flock were sexed by means of an optical device, wing-banded, weighed and distributed equally into electrically heated batteries where they had free access to water and …

Two levels of potassium (0.41 and 1.01%), two levels of phosphorus (0.24 and 0.57%) and two levels of calcium (0.28 and 1.20%) were used in a 2 × 2 × 2 factorially designed experiment to determine the influence of excess dietary potassium on feedlot performance and the formation of phosphatic urinary calculi in lambs fed various levels of phosphorus and calcium. A total of 240 Texas ewe lambs were allotted to the eight treatments. There was a tendency toward lower weight gains and feed consumption for lambs fed the higher level of dietary phosphorus. This effect was most pronounced in the presence of the highest level of potassium (1% potassium chloride added to the diet). Added calcium completely overcame these effects. No obstructive urinary calculi were observed in these ewe lambs. However, those fed the highest level of phosphorus and the lowest level of calcium had a 55 to 57% calculi incidence as determined at slaughter. While the incidence of urinary calculi was no different in the lambs fed the higher level of potassium, the average size of the urinary mineral deposits was larger amounting to 120 and 83 mg for lambs on treatments with and without 1% potassium chloride, respectively. Increasing the level of calcium to 1.20% of the diet reduced the calculi incidence to 17%. These data support the existence of a detrimental potassium-phosphorus interrelationship expressed in lambs fed elevated levels of each.

Nine treatment groups of lambs (14 to 16 per treatment) were fed rations containing various levels and ratios of calcium and phosphorus. Data pertaining to urolithiasis were obtained. No urinary calculi were observed in the groups receiving 0.33% of phosphorus in combination with levels of calcium ranging from 0.44 to 0.96%. A 31% incidence of urinary calculi was observed when 0.62% phosphorus and 0.44% calcium were fed. When the phosphorus content of the ration was increased to 0.81%, a 73% incidence of urinary calculi occurred. Increasing the level of calcium in the ration appeared to provide partial protection against the occurrence of urinary calculi in sheep receiving the higher levels of phosphorus.

STUDIES dealing with the effects of feeding cereal grains containing selenium to laying hens have been previously reported by Franke and Tully (1935) and Poley et al. (1937). It was also shown by Poley and Moxon (1938) that the use of more than 5 parts per million of selenium in the breeder ration resulted in lower hatchability, and that when the ration contained 10 p.p.m. of selenium the hatchability decreased to zero. It was observed that the growth and mortality rates of chicks hatched from hens receiving 5 p.p.m. of selenium in their ration were not appreciably affected when these chicks received starting rations containing no selenium. Tully and Franke (1935) showed that the feeding of selenized grains to chicks during the first eight weeks resulted in slow growth. The amounts of selenium included in the rations were not determined. The experiments reported here were conducted with two main objectives . . .

Rations containing 2.5 and 3.0% of added sodium nitrate were used in separate experiments to determine their effect on tissue vitamin A levels of sheep. Only small amounts of methemoglobin were found at regular bleeding periods in sheep receiving either level of nitrate, although seven sheep were lost from suspected acute nitrate poisoning while being fed 3% of sodium nitrate. Vitamin A offered no protection from nitrate poisoning. A transient increase in plasma vitamin A levels occurred about the middle of the first trial in sheep fed 2.5% of sodium nitrate and 2.5% of sodium nitrate plus 3000 I.U. of vitamin A. By the end of the trial, however, the values for these lots of sheep approximated the values obtained in sheep receiving corresponding non-nitrate treatments. No effect of nitrate on plasma vitamin A levels was observed in the second trial. However, lower liver vitamin A stores were found in the nitrate-fed sheep. After 56 days on experiment, sheep fed 3% of sodium nitrate had liver vitamin A concentrations that were 46.0% lower than those fed the control ration. Similarly, sheep fed 3% of sodium nitrate plus 4100 I.U. of vitamin A daily had liver vitamin A values 45.1% lower than those fed 4100 I.U. of vitamin A without nitrate.

Data collected on 860 purebred Hereford calves born in a continuing inbreeding project initiated in 1952 were used to evaluate the effects of inbreeding on growth and conformation and to evaluate present methods of adjusting for inbreeding effects. Two mating systems (MS) each with four sires were established. In one, mating was restricted to four single sire lines, and in the other, matings were restricted to a relationship less than half-sib. The two systems were formed from the same foundation animals by mating related animals for the foundation of the inbred system and by mating the same animals in unrelated pairs for foundation of the noninbred system. Inbreeding of the calves has reached the 30% level while inbreeding of the dams has reached the 25% level. Inbreeding effects were studied first by the use of within year-line-sire subclass regressions of trait on inbreeding. Inbreeding of calf and inbreeding of dam effects appeared to be more important on weaning traits than on post-weaning traits, although significant linear and quadratic effects of inbreeding were found at both ages. The inbred-noninbred comparisons indicate that for most traits the estimates of inbreeding effects obtained by within subclass estimation of regression coefficients accounted for most of the between MS variation. The major exception was weaning weight. Differential responses by the two sexes appeared in several of the different analyses. These results are discussed in relation to possible explanations of the presence of greater heterosis in the homogametic sex. From a practical standpoint the results indicate that breeders could close their herd and use as few as four initially unrelated bulls without suffering severe inbreeding effects. Even in the one sire lines, inbreeding effects which were severe at weaning for the female had partially declined by the yearling age. In breeding appeared to affect conformation even less than growth. Therefore, the mating system should be useful in purebred herds where it holds other advantages and where the herd is of sufficiently high merit to justify its use.

A total of 216 wether lambs were used in an experiment including feeding and balance trials. The lambs were fed a high-phorphorus basal ration, known to be calculogenic, supplemented with either 1% ammonium chloride,1% calcium chloride, 1% potassium chloride, 4% sodium chloride or 2% calcium carbonate. During an 88-day period, the control lambs developed a 50% incidence of urinary calculi. The calculi incidence for lambs fed the various salts were ammonium chloride, 5 %; calcium chloride, 16%; potassium chloride, 85%; sodium chloride, 35% and calcium carbonate, 30%. The reductions in urinary calculi incidence resulting from the feeding of ammonium chloride and calcium chloride, and the increase from the feeding of potassium chloride were significant (P<.05). Excretion and retention data dispute the existence of any protective action manifested through variations in excretion patterns of calcium, sodium, potassium or chloride unless accompanied by a concomitant reduction in urine pH. Average weight gain was reduced significantly(P<.05) by the feeding of 1% potassium chloride, and a reduction accompanying the feeding of 1% ammonium chloride approached significance at the same level of probability.

Eighty wholesale beef ribs from carcasses of four U.S.D.A. maturity levels (A, B, C and D) and two marbling levels (moderate and slight) were studied. The longissiums dorsi muscle was used for all tests. The three components of color (Munsell hue, value and chroma) were measured by the use of a Photovolt Reflection Meter. Myoglobin and hemoglobin determinations were made by converting these pigments to carbon monoxide compounds. Total pigment values obtained by adding these two pigments were compared with total values resulting from the use of a cyanmet conversion method. The carbon monoxide pigment values were analyzed statistically on fresh, moisture-free and moisture- and fat-free bases. Myoglobin and hemoglobin, on all three bases of analysis, increased with advancing maturity, but only between the A and the other three maturity levels were the differences significant. Marbling alone had no effect on myoglobin or hemoglobin. Of the three Munsell color components, only value was affected significantly by maturity, while only hue was influenced by marbling. Value decreased significantly with increasing maturity, but the differences were significant only at the A maturity level. Hue increased significantly with increased marbling. Significant correlations existed between myoglobin content and Munsell values, but the correlations were not large enough to derive a reliable predictive equation. Hemoglobin was not correlated significantly with Munsell value. Hemoglobin was negatively correlated with flavor, indicating that higher hemoglobin content was associated with more desirable flavor.

Subcutaneous implantation of 12 mg. stilbestrol in the jaw of suckling lambs failed to increase rate of gain in suckling lambs 2½–3 months of age. A slight but statistically insignificant increase resulted when suckling lambs 3½–4 months of age were treated. General type was not affected by treatment but an increase in the size of the mammary glands and formation of normal appearing milk was evident in the treated lambs. Testes growth was arrested but approximately 4–5 months post-treatment the testes appeared normal. Treatment of fattening lambs with 12 mg. stilbestrol increased rate of gain and feed efficiency significantly. Carcass grade was lowered considerably and carcass yield slightly. Treated lambs tended to shrink more following slaughter than control lambs. Total cooking losses including water vapor and drippings were of about the same magnitude in both groups. There was no difference in digestibility of the feed nutrients by the lambs in the two groups. Milligrams of nitrogen per milliliter of urine were approximately the same for both groups. However the treated lambs excreted considerably less urine and consequently excreted less nitrogen. Nitrogen retention was approximately 30 percent greater in the treated lambs. A severe outbreak of prolapse of the rectum, and uterus resulting in urinary blockage and death occurred in a band of 9,000 lambs treated with 12 mg. of stilbestrol.