Low Production Groups Research Articles

Norms for the diagnosis and recommendation integrated system for Signal grass

The Diagnosis and Recommendation Integrated System (DRIS) has been proved efficient as a method for nutritional diagnosis in several crops. However there is a lack of information on the use of DRIS for tropical forage grass. The aim of this paper was to establish norms for interpretation of results of analysis from recently expanded leaf laminae of Brachiaria decumbens Stapf. (Signal grass), through the DRIS method. To establish DRIS norms, concentrations of N, P, K, Ca, Mg, S, Cu, Fe, Mn, and Zn and the relative production obtained in six experiments conducted in greenhouse using nutrient solution and silica as substrate were considered. DRIS indices were calculated using two criteria in order to choose the ratio order of nutrients: F value - ratio of variance for the relationships among nutrients between the reference group and the low productivity group; and R value - correlation coefficients between the productivity values and the relationship among the pairs of nutrients, and three forms of calculation for the functions of nutrients (methods of Beaufils, of Jones, and of Elwali & Gascho). The two criteria to choose the ratio order of nutrients selected different ratios between pairs of nutrients; the nutrient concentrations were positively and significantly correlated with the respective DRIS indices, except for N; and DRIS norms are useful for the nutritional diagnosis of the ten studied nutrients in leaf laminae of Signal grass.

The Relationship between Changes in Serum Glycine and Alanine Concentrations in Non-Essential Amino Acid and Milk Production in the Transition Period in Dairy Cows

The serum concentration of non-essential amino acid (NEAA) was measured in ten Holstein dairy cows grouped as low production (n=5) and high production (n=5) from one month pre-partum through four months post-partum and the relationship between production and amino acid concentrations was studied. The glycine (Gly)/NEAA ratio and the glycine/alanine ratio of the high production group were significantly higher than the low production group (p<0.01). The observed decrease of the alanine (Ala)/NEAA ratio was more remarkable in the high production group than in the low production group. Measurement of Gly/Ala ratio in serum may be useful for evaluating the nutritional status of peri-parturient dairy cow.

Relationships of Circulating Concentrations of Insulin-like Growth Factor (IGF)-I and -II to Egg Production and Growth Rate in the Korean Native Ogol Chicken

Insulin-like Growth Factors (IGFs) and IGF-binding protein act as intra-ovarian regulators that modulate the proliferation and differentiation of the granulosa and theca cells. Moreover, the IGF system is involved in metabolism by modulating the synthesis and degradation of glycogen and protein in animals. However the effect of the IGF system on egg productivity or body growth in KNOC has not been studied in depth. Therefore, this study was performed to investigate differences of serum IGFs and binding protein expressions between two groups showing high and low egg production or body weight and to elucidate the relationship of IGFs with egg productivity and body growth. KNOCs were divided into high and low groups depending on their egg productivity or body growth, and sera were collected every 10 wk from 20 till 60 wk. Serum IGF-I and -II concentration were measured by RIA using human and mouse antiserum and chicken standards. IGFBP was detected by Western ligand blotting. IGF-I concentrations were significantly greater in the high egg production group compared with those in the low egg production group (30 wk, p<0.01; 20 and 40 wk, p<0.05). Also, differences in IGF-II amounts between the two groups were detected at 60 wk (p<0.05). But IGFBPs in the low egg production group were more intense than that in the high egg production group through the egg laying period. The correlation between IGF-I concentration and number of egg production is significantly positive (20 wk, r=0.2729: p<0.05; 40 wk, r=0.3500: p<0.01), while IGF-II shows no correlation with egg productivity. In male KNOC, IGF-I and -II concentrations in the high body weight group are lower than that in the low body weight group. Body weight also shows a negative correlation with the serum IGF-II concentration in male chickens (20 wk, r=-0.5901: p<0.01). Consequently, we suggest that IGFs and binding protein are (in)directly involved in the egg productivity and body growth in KNOC. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 4 : 481-488)

Non-Dietary Sources of Variation in Milk Urea Nitrogen in Ohio Dairy Herds

Protein is an expensive component of dairy cow diet and excessive protein feeding has been associated with decreased fertility. Urea is the end product of protein metabolism in dairy cattle. Milk urea nitrogen (MUN) can be used to monitor the protein feeding efficiency and protein-energy ratio in dairy cow rations. The purpose of this study was to describe the non-dietary sources of variation in and the factors associated with MUN levels in Ohio dairy herds. The data came from 24 herds belonging to Ohio Dairy Herd Improvement Association. Half of the herds (12) were classified as low producing herds (rolling herd average (RHA) milk production 10,433 kg). MUN concentration was measured spectrophotometrically from monthly test day milk samples by an automated procedure with a Skalar Segmented Flow Analyzer. We had observations from 12,939 test days, from 1681 cows. The data were analyzed using multilevel modelling technique in MLwiN ® , separately for both production groups. Different levels of organization were herd, cow, and test day. Initially, a simple random intercept model containing only a constant was run. Explanatory variables previously identified being associated with MUN were added to the model as fixed effects and model was reduced until all variables were significant at ?=0.05 level. The average MUN level from the simple intercept-only model was 14.1 mg/dl and 11.0 mg/dl in the high and low producing herds, respectively. The overall variation in MUN's was greater in low producing herds than in high producing herds. Also, the variance structure was quite different between these two groups. In low producing herds, 67.2% of the variation in MUN's was at the test day level, only 0.5% at cow level and 32.3% at herd level. In the high producing herds, however, highest proportion of variance (49.0%) was found at the herd level and 38.9% of the variation was at the test day level. Between-cow variability accounted for 12.1% of the variance in MUN's. With the independent variables in the model, variation was reduced in low production group (by 16%), but practically no change in magnitude took place in the high production group. The results also indicated that measurements taken during the first month of lactation were significantly lower than ones taken later in the lactation. Also, the season of the test day was associated with MUN levels (summer or spring with highest levels). Cow's test day milk yield and fat-protein ratio in milk in high producing herds were also positively associated with MUN levels. In low producing herds, milk fat percentage was negatively associated with MUN levels. The observed differences in the proportions of variance at the different levels between the production groups may be explained by management factors. Lower variability in MUN between test days in high producing herds probably indicates more consistent day-to-day feeding and management within a herd in this group.

Planktic foraminiferal production stimulated by chlorophyll redistribution and entrainment of nutrients

During September and October 1996 planktic foraminifers and pteropods were sampled from the upper 2500 m of the water column in the BIOTRANS area (47°N, 20°W), eastern North Atlantic, as part of the JGOFS program. Hydrography, chlorophyll fluorescence, and nutrient content were recorded at high spatial and temporal resolution providing detailed information about the transition time between summer and fall. At the beginning of the cruise a shallow pycnocline was present and oligotrophic conditions prevailed. Over the course of the cruise, the mixed layer depth increased and surface water temperature decreased by 1.5°C. Both chlorophyll- a dispersed in the upper 50 m by vertical mixing and chlorophyll- a concentrations at the sea surface increased. The nitracline shoaled and nutrient enriched waters were entrained into the mixed layer. Planktic foraminifers and pteropods closely reflected the changes in the hydrography by increased growth rates and changes in species composition. Three main groups of planktic foraminiferal species were recognized: (1) a temperate and low-productivity group dominated by Neogloboquadrina incompta characterized the shallow mixed layer depths. (2) A temperate and high-productivity group dominated by Globigerina bulloides characterized the period with wind-induced dispersal of chlorophyll- a and entrainment of nutrient-enriched waters. (3) A warm water group containing Globigerinoides sacculifer, Orbulina universa, Globigerinoides ruber (white), and Globigerinella siphonifera was most common during the first days of sampling. Synchronous with the hydrographic change from summer to fall, planktic foraminiferal and pteropod growth was stimulated by redistribution of chlorophyll- a and entrainment of nutrient-enriched waters into the mixed layer. In addition, the seasonal change in the eastern North Atlantic resulted in a transition of the epipelagic faunal composition and an increased calcareous particle flux, which could be used to trace seasonality in fossil assemblages and allow for better paleoceanographic interpretation of the boreal Atlantic.

Effect of milk production on the incidence of double ovulation in dairy cows

To determine the effect of parity and milk production on the incidence of double ovulation, the synchronization of ovulation, using GnRH and prostaglandin F 2α followed by timed AI (Ovsynch ®), was initiated at a random stage of the estrous cycle in lactating Holstein cows (n=237). Ovulatory response at 48 h after the second GnRH injection and conception rate at 28 d post AI were determined by transrectal ultrasonography. Ovulation was synchronized in 84% of cows receiving the Ovsynch ® protocol. Of the synchronized cows, 14.1% exhibited a double ovulation and 47.6% conceived. Conception rate tended to be greater ( P=0.08) for cows exhibiting double (64.0%) rather than single ovulation (45.2%). To determine the effect of milk production on the incidence of double ovulation, cows were classified into low (≤ 40 kg/d) or high (> 40 kg/d) milk production groups based on the average milk production of 40.5 ± 0.8 kg/d collected 2 d before AI. Although the incidence of double ovulation tended to increase linearly ( P=0.09) with increasing parity, the incidence of double ovulation was nearly 3-fold greater ( P<0.05) for cows in the high (20.2%) than the low (6.9%) milk production group. Furthermore, the increase in the incidence of double ovulation with parity apparently occurred because, within a parity group, the proportion of cows with high milk production was greater for the older cows. Twinning rate of cows that calved (n=58) was 5.2%. In a secondary objective, cows were retrospectively classified as cystic or normal based on ultrasonographic ovarian morphology at the time of the second GnRH injection. Incidence of ovarian cysts was 11%, and the synchronization and conception rate of cows classified as cystic was 73.1 and 36.8%, respectively, which did not differ from that of normal cows. We conclude that milk production is the primary factor affecting the incidence of double ovulation in lactating dairy cows and may explain the effect of parity on twinning rate. In addition, Ovsynch ® appears to be an effective method for establishing pregnancy in lactating dairy cows with ovarian cysts.

Information systems variables and management productivity

The companies in the Premier 100 list published by ComputerWorld (CW) in 1994 were classified into groups based on the information productivity index (IPI) computed by Paul Strassmann. Discriminant analysis was used to identify the significant discriminating information systems factors between the two groups. They are: ‘number of years the Chief Information Officer (CIO) has been in the company in that position,’ ‘proportion of software resources spent on client server applications,’ and ‘percentage of software budget spent on new development.’ On average the CIOs in the high productivity group have been with the company for three years, as compared to eight years in the low productivity group. The companies in the high group spent 54% of the software development budget on client server applications, as compared to 35% for the low productivity group. Companies in the high productivity group spent 46% of software budget on in-house development of new applications, as opposed to 60% for the low productivity group.

Calcareous nannofossils as paleoproductivity indicators in Upper Cretaceous organic-rich sequences in Israel

Abundant and diverse calcareous nannofossil assemblages were found in organic-rich carbonate sequences which accumulated in a Campanian-Maastrichtian upwelling belt along the southeastern Tethys. The sequences studied represent the inner (shallower) and the outer (deeper) parts of the upwelling belt. The paleoenvironmental significance of selected nannofossil taxa and their utility in productivity reconstruction was established by comparing their distribution to foraminifera and dinocyst-based productivity profiles. Based on the calcareous nannofossil assemblages, a high-productivity group and a low-productivity group of species were determined. The distribution of these groups agrees well with the dinocyst- and foraminifera-based productivity curves and, hence, can be used to record paleoproductivity changes. The ratio between the high-productivity and low-productivity nannofossil groups, the Nannofossil Index of Productivity (NIP), is proposed here as a productivity proxy that can be utilized in reconstructing basinal productivity development. A quantitative analysis of the nannofossil assemblages indicates that their abundance and diversity increase towards the open sea, in the outer and less productive part of the upwelling belt. In the inner and more productive part of the upwelling belt, the nannofossils assemblages become less abundant and less diverse relative to those of the open marine environment. Micula decussata and Watznaueria barnesae are common to abundant in most samples. M. decussata becomes more abundant in poorly-preserved samples. On the other hand, the distribution of W. barnesae matches better with intermediate productivity levels.

Use of cow-side progesterone tests to improve reproductive performance of high-producing dairy cows

This study evaluated the effectiveness of the cow-side ELISA milk progesterone test in improving postpartum reproductive performance in the Dordt College dairy herd. Cows that produced more than 18,500 lb of milk per lactation were assigned to the high production group (40 cows), while cows that produced less than 18,500 lb of milk (42 cows) were assigned to the low production group. Twenty-one cows in the high production group and 19 cows in the low production group received no ELISA testing (untreated controls), while the remaining cows in each group were evaluated by ELISA test every 7 d beginning on Day 27 post partum (treated cows). A sequence of 2 high progesterone tests and 1 low test indicated the cows were cycling normally. Cows that had low milk progesterone levels (<5 ng/ml) for 3 consecutive tests were assumed to have follicular cysts and were treated with 2 ml GnRH (Cystorelin, 50 μg/ml). Cows that had 3 consecutive high tests (>5 ng/ml) were assumed to have persistent corpora lutea (CL) and were treated with 5 ml PGF 2α (Lutalyse, 5 mg/ml). In both the high and low production groups, treated cows had higher (P < 0.08) pregnancy rates by Day 210 than the untreated controls (63.2 vs 38.1% and 56.5 vs 42.1%, respectively). The days open were reduced (P < 0.05) for the treated animals by 41.6 d compared with the controls. The treated cows produced a net savings of $70.42 (US) per cow assuming a $3.00 savings/day open.

Effects of Low and High Fill Diets on Intake and Milk Production in Dairy Cows

Thirty-four lactating dairy cows were allotted to two groups based on previous lactation mature equivalent 305-d milk production (average 30 and 23 kg/d) and assigned randomly to four dietary treatments. Diets with slow (high fill) or fast (low fill) estimated rates of NDF disappearance, with or without the addition of 1.5% sodium bicarbonate, were limit-fed 2 wk prior to calving, then fed for ad libitum consumption until 10 wk postpartum. In a summary of pooled data from high and low production groups, average milk and milk protein production (kilograms per day), and NDF and ADF in-takes on a percentage of BW basis were higher for cows given the low fill diet (35.22 vs. 32.07, 1.13 vs. .97, 1.16 vs. 1.05, and .58 vs. .51, respectively). Production of 4% FCM, milk fat, and percentages of milk protein and fat were not affected by diet. Dry matter intake and mean BW did not differ significantly among diets. The addition of sodium bicarbonate had no effect on production responses.

Comparison of Different Methods of Expressing Dietary Protein for Lactating Dairy Cows

Data were from Holstein cows from 20 experiments at the University of Florida (1688 cow-period observations). Objectives were to compare milk responses to increasing dietary percent or daily intake of CP, estimated undegradable CP, and estimated metabolizable protein from Burroughs and Chalupa equations and to determine if higher producing cows (26.8kg milk/d) responded differently to increasing dietary protein percent or intake than do lower producing cows (18.9kg milk/d). The mathematical model included experiment, cow-within-experiment, period, body weight, and source of roughage. Intake of protein (kg/d) had a greater effect (cubic polynomial) on milk yield than protein percent of DM since CP, undegraded protein, Chalupa metabolizable protein, and Burroughs metabolizable protein intakes explained 17.2, 20.9, 23.5, and 24.1% of residual variation in milk yield compared with .6, 2.1, 1.7, and 2.1%, for percents of DM. High producing cows responded more to increasing protein intake than did low producing cows. Respective protein intake variables explained 20.6, 23.7, 30.5, and 31.2% of residual variation in milk yield in high production group compared with 17.2, 23.1, 20.6, and 20.6% in low production group.

An empirical study of autonomous work groups relationships between worker reactions and effectiveness

This paper reports on findings from an empirical study of thirty autonomous work groups, It deals with systems at the group level, particularly their producer and decider subsystems. Each work group operated within the same organization, making the same kind of product using the identical process. This study attempts to explain the differences between high productive and low productive autonomous work groups. The focus is on two key areas of worker perceptions: satisfaction with the job and perceptions of work group leadership. Results show the importance of establishing and communicating a policy of promotional opportunities to reward high performance. Leadership dimensions (superior orientation and consideration) that discriminate between high and low production groups are identified. These findings have implications in the selection and training of team leaders and the management of autonomous work groups.

Trends in Genetic and Phenotypic Variances for Milk Production

Residual standard deviations estimated separately for each year of first freshening from first lactation milk records of artificially sired Holstein cows increased from 1960 to 1982, especially after 1976. The pattern on the square root scale was similar. On the logarithmic scale, residual standard deviations were smallest in the middle of the time period. Heritabilities estimated from paternal half-sib correlations were greater than .30 on all scales until about 1976 when estimates began to go below .20. Estimates were similar for untransformed and transformed records. When records were divided into four herd production groups within each year, the same patterns over time for residual standard deviations were observed as for the combined data for each year. On the untransformed scale, the largest standard deviations were associated with high herd production and the smallest with low herd production. On the square root scale, standard deviations were similar for all herd production groups. On the log scale, residual standard deviations were smallest with high production and largest with low production—the reverse of the untransformed scale, although differences were smaller. Heritability was highest with middle-production groups and smallest with low-production groups. Data available for each year ranged from 1,400 and 2,849 to 6,821 and 58,082 records, respectively, of daughters of sampling and proved bulls with from 115 to 513 sampling bulls.

Short estrous cycles in postpartum cows as influenced by level of milk production, suckling, diet, season of calving and interval to first estrus

The frequency of short cycles after the first postpartum estrus was determined from data collected in three experiments. Short estrous cycles (SEC) were defined as those less than 17 days long. Cows that were bred at the first estrus postpartum and conceived were included in the non-short cycle count. In Exp. 1, designed to determine the influence of genetic ability for milk production on postpartum traits, 16 of 118 Holstein cows (13.6%) had short estrous cycles. The incidence of SEC was greater in the low milk production group, but the differences were not significant (P>.25). This group had a shorter mean postpartum interval to first estrus (PPI) when compared to the high milk production cows (P<.025). Exp. 2 was designed to test the influence of suckling versus nonsuckling on postpartum traits, and seven of 54 Angus cows (13.0%) had SEC. The incidence of SEC in suckled and nonsuckled cows was 2 26 and 5 28 , respectively (P<.25). The nonsuckled cows had a shorter (P<.005) PPI than suckled cows. When these cows were grouped according to winter or summer calving, the incidence of SEC was 1 20 vs 6 34 (P<.25). In Exp. 3, designed to determine breed of sire x nutrition interactions on postpartum traits, there were 14 SEC out of 174 (8.0%) first estrous cycles in three parities of 58 crossbred cows. There was a tendency (P<.15) for more SEC to occur in the high nutrition group, but this may have been due in part to two cows in the high nutrition group that exhibited SEC in more than one parity. The high nutrition group also tended (P<.10) to have a shorter mean PPI than the low nutrition group. In all experiments, there were more SEC among cows displaying first estrus before 20 days postpartum.

Feeding and Managing Dairy Cows in Three versus One Production Group

Lactating Guernsey and Holstein cows were assigned randomly to either a statified here with high, medium, and low production groups or a one-group control herd. Complete rations were formulated to meet National Research Council requirements for average milk production of the group (medium and low) or group average plus 10% (high and control). Cows in the stratified herd were regrouped at monthly intervals.Mean body weights and average daily intakes of hay, silage, and concentrate over 3 yr were similar between treatments. Stratified and control herds did not differ significantly in milk production adjusted for age and season, fat, or reproductive performance. Stratified Guernsey in first lactation produced more milk and required fewer services per conception than controls. Lactation persistency of cows in the stratified herd was unaffected by intergroup transfer. Stratified cows had higher mean monthly Wisconsin Mastitis Test scores.

Effects of Moderate Heat and Milk Yield on Plasma Thyroxine in Cattle

The effects of milk yield (lactational intensity) and short (18h) moderate heat exposure (30C) on plasma thyroxine were studied in spring (March) and fall (October) in the University of Missouri dairy herd. Spring and fall thyroxine did not differ at thermoneutral temperature of 15C. The relatively short moderate heat exposure had no effect within production groups either in the spring or fall sampling. As stage of lactation progressed, thyroxine also increased. The effect of stage of gestation was an elevation in the first trimester (compared to nonbred) that progressed into the second and third trimesters. In both spring and fall (15C), the high production group (adjusted and unadjusted) had lower plasma thyroxine compared with middle and low production groups, while no difference in adjusted means was significant between middle and low production groups. Correlations were –.51 between plasma thyroxine and lactational intensity in both spring and fall. The short exposure to moderately high environmental temperature intensified the relationship of lowered plasma thyroxine in high producing cows, and thyroxine was negatively correlated (–.63 and –.64) with lactational intensity. Because total plasma thyroxine is inversely related to lactational intensity, studies are warranted to quantitate free hormonal concentrations and utilization by dairy cattle with varying productivity.