Showing papers in "Journal of Animal Science in 1976"

Effect of Monensin Fed with Forage on Digestion and the Ruminal Ecosystem of Steers

Abstract: Monensin 3 , a polyether antibiotic, was blended with a forage diet at levels of 0, 11, 22 and 33 ppm and fed to steers to determine its effect on cot ton fiber, dietary carbohydrate and nitrogen digestibility, on numbers of rumihal microbes, and on concentration of ruminal volatile fa t ty acids. No differences (P>.10) in cellulose digestibility from cot ton were observed in response to monensin level when cot ton fiber samples were incubated in vitro in ruminal fluid from these steers. Neither were differences in loss of dry mat ter detectable (P>.10) when cot ton fabric strips were placed within the rumens of steers for 72 hours. In v/vo digestion of dry matter, crude protein, hemicellulose and cellulose of the forage diet was not different (P>.05) among treatments. Total ruminal volatile fa t ty acid concentrat ion was not affected by feeding monensin, but the molar proport ion of acetic acid decreased (P<.01) from 66.7 to 61.3% and that of propionic acid increased (P<.01) from 20.1 to 26.1%. No other volatile fat ty acids were affected. Neither the numbers of protozoa, total bacteria nor cellulolytic bacteria in rumihal fluid were affected by feeding up to 33 ppm dietary monensin. (

Growth, development and composition of the udder and gravid uterus of beef heifers during pregnancy.

Abstract: Forty-six Hereford heifers were slaughtered at different stages of gestation. Udders and gravid uteri were removed. Each gravid uterus was dissected into fetus, fetal membranes, fetal fluids and uterus. Fresh weights, dry matter, ether extract, ash, nitrogen and gross energy contents of the various tissues were determined. Weights and compositions of udders and uteri from 36 non-pregnant heifers were also determined. Relationships of the type W = Woe (b~-b2t) t where t is the number of days after mating, Wo is the amount of constituent on the day of mating and W is the amount of constituent on day t of gestation were derived to describe growth of different constituents of the gravid uterus during gestation. Udder development was most rapid after 234 days of gestation as indicated by ash and nitrogen contents. Udders of pregnant heifers contained approximately 48, 60, 67 and 102 g nitrogen at 134, 189, 237 and 264 days of gestation, respectively and udders of non-pregnant heifers contained approximately 37 g nitrogen. No net accumulation of energy occurred in udders of pregnant heifers re/ative to that gained in udders of non-pregnant heifers. Fetuses averaged 1.58, 7.53, 20.8 and 31.6 kg and contained 1.20, 1.60, 2.07 and 2.52% nitrogen at 134, 189, 237 and 264 days of gestation, respectively. Gross energy contents of fetuses were .54, .88, 1.17 and 1.32 kcal/g fresh weight at each of these times. Rates of nitrogen and energy storage in the gravid uterus were estimated to be .76, 2.79, 8.95 and 25.0 g/day and 36.0, 143,457 and 1,167 kcal/day at 100, 160, 220 and 280 days of gestation, respectively. None of these values was affected by fetal sex or maternal energy intake (150 or

Influence of carbohydrate solubility on non-protein nitrogen utilization in the ruminant.

Abstract: Although soluble carbohydrates and carbohydrate solubility may sound synonymous, they, in fact, are not when one considers their influence upon the fermentat ion in the rumen. The former refers to a restricted class of carbohydrates of specified solubility whereas the latter portrays a characteristic of any carbohydrate or group of carbohydrates that often can be modified by pH and concentration as well as by chemical, physical, and microbial processing techniques. As such, the lat ter characteristic becomes more critical in a discussion of effects on non-protein nitrogen (NPN) utilization. This review is in no way an exhaustive review of the effects o f all forms of carbohydrate or NPN utilization. The subject of NPN utilization has been reviewed many times, most recently by Helmer and Bartley (1971). Far too many of the li terature citations which could be cited represent repetitive findings which contr ibute very litt le definitive or new information to our information bank on NPN utilization. References quoted herein are primarily for the purpose of setting the stage for the ideas and challenges to be presented. In effect then, the purpose of this paper is to stimulate the future investigators of this topic to (1) investigate newer, more novel areas of research, (2) accept the challenge of improving research techniques so that really new information can be obtained using them, and concurrently, (3) abandon those techniques which, although traditional, are not particularly definitive and are often a waste of t ime and effort.

Ovarian function and estrus in dairy cows during early lactation.

Abstract: The onset of ovarian function and occurrence of estms were monitored in two groups of Holstein cows over the first 90 days postpartum. Group 1 consisted of 36 animals housed in a free stall area and observed continuously for estrus with closed circuit television and a time lapse videorecorder. Group 2 consisted of 33 cows housed in tie stalls with estrus detected by the herdsmen. Blood samples were collected twice weekly and assayed for progesterone. The plasma progesterone profiles were used to monitor ovarian function and determine ovulation time. In both groups there was close agreement between basal progesterone concentrations and observed estrous activity. There was no difference between the groups in the incidence of abnormal ovarian activity, or in the interval from parturition to first, second or third ovulation. For all cows with normal ovarian function, the median time to first ovulation was 19.5 days and the time to the second and third ovulation was 44.4 + 13.2 and 63.7 + 10.1 days, respectively. A significant difference was observed between the two groups in the days from parturition to first detected estrus: Group 1, 34.5 + 12.8; Group 2, 56.6 -+ 26.5, (P>.01) and in the percentage of cows in which estrus was detected at the first, second and third ovulation: Group 1, 50%, 94% and 100%; Group 2, 20%, 44% and 64%, (P<.01). (

Degradation of Amino Acids by the Mixed Rumen Microbial Population

Abstract: Degradation of physiological quantities of amino acids by rumen microbes was determined under both in vitro and in vivo conditions. In vitro rate constants for EAA indicated that Arg and Thr were rapidly degraded (.5 to .9 mM/hr); Lys, Phe, Leu and lie formed an intermediate group (.2 to .3 mM/hr); and Val and Met were least rapidly degraded (.1 to .14 mM/hr). In vivo EAA degradation rates were about 1.bx greater than estimates derived from in vitro rate constants, but a significant (P<.05) linear relationship between in vitro and in vivo rates suggested that similar degradative pathways predominated in both systems. Incubating Thr, Arg, Lys, Phe, Leu and lle alone or in combination with a mixture of EAA yielded similar amounts of degradation for these EAA. Met and Val degradation was approximately twice as great (P<.05) when fermented alone vs in conjunction with other EAA. Combining a mixture of NEAA (Asp, Ser, Glu, Ala, Tyr, Orn) with the EAA mixture did not influence EAA degradation. Tyr and Orn were the only NEAA degraded to lesser (P<.05) extents (30%) when the fermentation system contained both NEAA and EAA mixtures. Data presented demonstrated that specific amino acids are degraded at different rates and that there are interactions between certain amino acids. With the possible exception of Met, supplements of free amino acids cannot survive ruminal degradation. (

Influence of Freeze Rate, Thaw Rate and Glycerol Level on Acrosomal Retention and Survival of Bovine Spermatozoa Frozen in French Straws

Abstract: A three-dimensional central composite design was used to study the effect of glycerol level, freeze rate, and thaw rate on acrosomal retention and percent motility. Glycerol levels examined were: 1, 4, 7, 10 and 13%. Average freeze rates between 1 0 and 8 0 C examined were: 6.5, 13.1, 26.3, 52.5 and 105.0 C/minute. Thaw rates studied were achieved by plunging straws into water at 5 C for 2 rain, 20 C for 1 min, 35 C for 30 sec, 50 C for 15 sec and 65 C for 7.5 seconds. Percent motility and percent intact acrosomes for one ejaculate from each of 12 bulls were recorded post-thaw at 0, 3, 6 and 9 hr of a 37 C-incubation. The multiple regression model (mean of 0-, 3-, 6and 9-hr incubation periods) described the experimental data adequately (r 2 = .83, acrosomes; r 2 = .74, motility). Glycerol level was significant (P<.01) as a quadratic component for both intact acrosomes and motility. Thaw rate was significant as a quadratic component for intact acrosomes (P<.01)and motility (P<.05). The interaction of glycerol and thaw rate was of greatest importance (P<.01). As the thaw bath temperature was increased, optimum glycerol level also increased in achieving maximum motility and acrosomal integrity. Freeze rate was relatively unimportant. Using the average freeze rate of 26.3 C/rain from 1 0 to 8 0 C, minimal cell injury was calculated to be achieved with 8.5% glycerol and a thaw water temperature of 65 C.

Influence of elevated ambient temperature on reproductive performance of boars.

Abstract: SUMMARY Twelve Yorkshire boars were randomly as- signed to one of two temperature controlled chambers to determine the influence of ele- vated ambient temperature on reproductive performance. Heat stressed boars were exposed to 34.5 -+ 1.0 C for 8 hr and 31.0 + 1.0 C for 16 hr daily for 90 days. Control boars were maintained at 23.0 -+ 1.0 C throughout the experimental period. Semen was collected twice weekly to determine sperm output and quality. Semen volume and gel weigh per ejaculum were not altered during elevated ambient tempera- ture. However, sperm motility and percent normal cells with non-aged acros'omes decreased and the percentage of abnormal cells and cells with aged acrosomes increased by the second week of treatment. Sperm output was reduced in stressed boars during weeks two through six of treatment. Only 28.6% of 77 gilts bred with semen from stressed boars conceived compared to 41.2% of 88 gilts bred with control semen. At day 30 + 3 of pregnancy, embryonic survival was 71.2 + 3.7% in gilts bred with semen from control boars and 48.5 + 5.2% for gilts bred with semen from stressed boars. (Key Words: Boar, Heat Stress, Semen, Sperm Morphology, Swine Reproduction.) 2Journal Article No. 3009 of the Agricultural Experiment Station, Oklahoma State University, Still- water, Oklahoma. This research was conducted in cooperation with the U.S.D.A., Agricultural Research Service, Southern Region. UAppreciation is expressed to Dr. R. K. Johnson and L. D. Young for assistance with the statistical analyses. 3Department of Animal Sciences and Industry, Oklahoma State University, StiUwater 74074. *Present address: Department of Animal Science,

Relationship of acidosis to other feedlot ailments.

Abstract: Laminitis often follows lactic acidosis and is accompanied by increased blood and rumen histamine. However, since histamine is poorly absorbed and absorbed histamine is rapidly metabolized, and since high levels of oral histamine have not produced laminitis, it is unlikely that ruminal histamine causes laminitis. Lactic acidosis leads to rumenitis, which, in turn, leads to liver abscesses because the causative microorganism can now cross the rumen wall into portal circulation. In cattle, hair ingested during grooming may penetrate the rumen wall and aid in this passage. Immunizing cattle against liver abscesses may be possible. Polioencephalomalacia occurs because an enzyme, thiaminase, develops in the rumen, catalyzing the production of a thiamin antagonist. Lactic acidosis may set up ruminal condit ions that encourage this chain of events. (

Effect of cooling, storage, glycerolization and spermatozoal numbers on equine fertility.

Abstract: The effects of cooling, storage, glycerolization and spermatozoal numbers on fertility were investigated utilizing three stallions and 72 mares. Semen was extended in a cream-gel extender and inseminated: a) within 1 hr (fresh) at 38 C, b) after cooling for 2 hr to 5 C, c) after cooling for 2 hr plus the addition of 7% (v/v) glycerol, and d) after cooling for 24 hours. Onehalf of the mares were inseminated with 100 and one-half with 500 • 106 progressively motile spermatozoa per insemination. Firstcycle pregnancy rates of 55.6, 38.9, 5.6 and 27.8% were obtained with the fresh, cooled 2 hr, cooled 2 hr plus glycerol and the cooled 24hr seminal treatments, respectively; after three cycles, the pregnancy rates were 94.4, 83.3, 44.4 and 55.6%. The fertility of freshly extended semen was superior (P<.05) to that of semen cooled for 2 hr plus glycerol and to semen cooled and stored for 24 hours. Semen cooled for 2 hr was superior (P<.05) to semen cooled for 2 hr plus glycerol. The 63.9% pregnancy rate for mares inseminated with 100 x 106 did not differ (P>.05) from the 75.0% for mares receiving 500 • 106 spermatozoa. There was no difference in fertility among the three stallions. (

Seasonal changes in sexual activity and serum levels of LH and testosterone in Finnish Landrace and Suffolk rams.

Abstract: SUMMARY A procedure for assessing sexual activity (libido) in individual rams is described. Mating activity measured by this procedure and serum levels of luteinizing hormone (LH) and testosterone in Finnish Landrace and Suffolk rams was determined at 8-week intervals from October, 1974 through October, 1975. Seasonal changes were observed for serum LH, testosterone and libido index scores. Mating activity in rams was highest for both breeds during the peak breeding season (October) and declined 50% by late spring and summer before it increased the next October. Serum LH concentrations were lowest in May (.54 ng/ml) and increased abruptly in July (>2 ng/ml) when daily photoperiod began to decrease. Serum testosterone concentrations (>6 ng/ml) and mating activity were highest during the October evaluations. Testosterone decreased gradually through the winter months and reached its lowest levels in late March (2.06 ng/ml in Finn rams and 1.01 ng/ml in Suffolk rams). Thereafter, concentrations gradually increased to levels observed the previous fall. A positive correlation (r = .59) between mean testosterone and mating scores collected across months suggested that seasonal fluctuations in serum testosterone influence the sexual behavior of rams. A temporal relationship was not detected between circulating testosterone and