Type of cottonseed and level of gossypol in diets of lactating dairy cows: effects on lactation performance and plasma gossypol

Objectives were to determine the effects of feeding whole linted Upland (WUP) and cracked Pima cottonseed (BUPCP) to lactating cows on plasma gossypol concentrations and lactation performance. Holstein cows (n = 813) from three commercial dairies were assigned to one of two diets starting at 13+/-11 d in milk (DIM) for a 170-d experimental period. Cottonseed was included at 10% of the diet dry matter, and treatments consisted of replacing WUP with a 1:2 blend of BUPCP. Blood was collected from all cows at 61 and 91 DIM and from a subset of 56 cows on one dairy at 10, 33, 61, 91, 120, and 152 DIM. Intakes of free gossypol increased 32% in cows receiving the BUPCP diet, and concentrations of total gossypol (TG), as well as the proportion of TG as minus (-) isomer in plasma, were higher for cows fed BUPCP than WUP. Plasma TG increased linearly with increasing DIM, but cows fed the BUPCP, especially multiparous cows, had a higher increase in plasma TG over time. Yields of milk and milk components did not differ between the two treatments, although, yields of milk and milk components were greater in cows with higher plasma TG. Replacement of WUP cottonseed with BUPCP cottonseed increased plasma gossypol, but dry matter intake and yields of milk and milk components were not affected.     

Effects of prepartum 2,4-thiazolidinedione on metabolism and performance in transition dairy cows

Thiazolidinediones (TZD) are potent synthetic ligands for peroxisome proliferator-activated receptor-γ that have been shown previously to reduce plasma nonesterified fatty acids and increase peripartal dry matter intake (DMI) in dairy cows. Data from Holstein cows (n = 36) entering their second or greater lactation were used to determine whether late prepartum administration of TZD would affect periparturient metabolism, milk production, and ovarian activity. Cows were administered 0, 2.0, or 4.0 mg of TZD/kg of BW by intrajugular infusion once daily from 21 d before expected parturition until parturition. Plasma samples were collected daily from 22 d before expected parturition through 21 d postpartum and twice weekly from wk 4 through 9 postpartum. In response to increasing TZD dosage, plasma nonesterified fatty acid concentrations decreased linearly during the postpartum period (d 0 to +21: 348, 331, 268 ± 31 μEq/L, respectively). Plasma concentrations of glucose were highest in cows administered 4.0 mg of TZD/kg of BW during the peripartum and postpartum periods (d −7 to +7: 57.9, 57.8, 61.1 ± 0.8 mg/dL and d 0 to +21: 51.6, 49.3, 54.7 ± 1.1 mg/dL, respectively). Plasma concentrations of β-hydroxybutyrate were increased during the peripartum period by TZD administration (9.6, 9.9, 10.2 ± 0.3 mg/dL) but were not affected during the postpartum period. Plasma insulin was not affected by treatment during any time period. Postpartum liver triglyceride content was decreased linearly (11.0, 10.4, 4.2 ± 1.6%) and glycogen content was increased linearly (2.16, 2.38, 2.79 ± 0.19%) by prepartum TZD administration. Prepartum TZD administration linearly increased DMI during the peripartum period (d −7 to +7: 16.1, 17.2, 17.3 ± 0.5 kg/d). Cows administered TZD prepartum maintained higher postpartum body condition scores than control cows (wk 1 through 9: 2.77, 2.89, 3.02 ± 0.05). There was no effect of prepartum TZD on milk yield; however, yields of 3.5% fat-corrected milk (52.2, 54.6, 48.0 ± 1.6 kg/d) and most other milk components were decreased in cows that received 4.0 mg of TZD/kg of BW prepartum. Prepartum TZD administration linearly decreased the number of days to first ovulation (29.3, 28.3, 19.0 ± 3.6 d). These results suggest that prepartum administration of TZD improves metabolic health and DMI of periparturient dairy cows and may decrease reliance on body fat reserves during early lactation.     

Lipopolysaccharide challenge following intravenous amino acid infusion in postpartum dairy cows: II. Clinical and inflammatory responses

Amino acids (AA) are integral nutrients for a functioning immune system. Postpartum cows experience AA deficits early postpartum that may influence the response to immune activation. This study investigated the clinical and inflammatory responses to a systemic inflammatory stimulus after a 4-d intravenous (IV) AA infusion with a mix of essential and nonessential AA designed to ameliorate the estimated metabolizable protein deficit in early postpartum cows. Our objectives were (1) to describe the clinical and inflammatory response to an acute IV lipopolysaccharide (LPS) challenge in early postpartum cows, and (2) to compare these clinical and inflammatory responses between IV AA-treated and control cows. Cows (n = 14, 4 ± 1 d in milk) were continuously infused IV for 4 d in a matched-pair randomized controlled design and received 0.9% NaCl (CTRL) or IV AA (IVAA) to supply 1 g/kg of BW per day of combined essential and nonessential AA. After infusion ended, cows were challenged with IV LPS (0.0625 µg/kg of BW over 1 h), and serial blood samples were collected for complete blood cell counts and to quantify plasma cytokines and acute-phase proteins. Body temperature, heart rate, and respiratory rate were monitored for 24 h during challenge. During challenge, maximum body temperature was greater in IVAA (41.3 ± 0.20°C) than in CTRL (40.6 ± 0.19°C). In both groups, respiratory rate increased during the first 2 h following challenge, whereas heart rate first decreased over the first 2 h and then increased to reach a maximum at 4 h. Acute leucopenia occurred within 1 h of challenge in both groups before leukocytosis was observed at 24 h, with white blood cell counts returning to baseline values within 72 h. Plasma haptoglobin and serum amyloid A concentrations increased 3-fold and 4-fold in both groups and peaked at 48 and 24 h following challenge, respectively. Plasma concentrations of TNF-α and IL-10 increased within 1 h and peaked at 2 h following the start of challenge. Plasma IL-10 concentrations increased to a greater extent in CTRL compared with IVAA during challenge. Despite differences in IL-10 concentration, previous AA infusion did not alter the acute-phase protein response to LPS challenge. We conclude that AA infusion before systemic inflammatory challenge decreased the anti-inflammatory response but did not alter concentrations of other systemic markers of inflammation.     

Short communication: Repeat breeder cows with fluid in the uterine lumen had poorer fertility

The objective of the present study was to test the association between the presence of fluid in uterine lumen and the fertility of repeat breeder cows (RBC). Grazing Holstein cows that were clinically normal and were not pregnant after at least 3 consecutive inseminations were defined as RBC and included in the study (n = 358). A cut-point ≥2 mm of uterine lumen visible by ultrasonography was used as indicative of the presence of fluid in the uterus. The effect of this fluid on the fertility of RBC was assessed by mixed logistic regression. Twenty percent of the RBC had ≥2 mm of fluid in their uterus, and this finding was associated with a marked reduction in the odds of conception (odds ratio = 0.46). Additional intrauterine sampling revealed that 24.0% of RBC showed signs of subclinical endometritis [≥5% neutrophils in endometrial cytology (SCE)]. However, we found no agreement between the finding of uterine fluid and the diagnosis of SCE (kappa coefficient = 0.03, 95% confidence interval = ?0.07 to 0.14). In conclusion, the presence of fluid (≥2 mm) in uterine lumen, detected by ultrasonography, was associated with lower fertility in RBC, but was not related to the diagnosis of SCE. Thus, ultrasonographic evaluation is an important tool to assist in assessment of RBC.     

Effect of feeding cows in early lactation with diets differing in roughage-neutral detergent fiber content on intake behavior, rumination, and milk production

This study measured the effects of including soyhulls as partial roughage replacement in total mixed rations (TMR) fed to 25 pairs of cows during early lactation, on the dry matter (DM) intake, particle kinetics, rumination, in vivo DM and NDF digestibility, milk and FCM yields, and BW changes. The 2 diets used in this study differed in the content of roughage and roughage NDF [23.5 vs. 35.0%, and 12.8 vs. 18.7% in the experimental (EXP) and control (CON) TMR, respectively]. The EXP TMR contained 20.5% less physically effective NDF than the CON TMR (11.7 vs. 14.1% of DM, respectively). These differences were expressed in a greater intake per meal (by 13.3%), a higher rate of meal intake (by 23.2%), a similar number of meals per day, a shorter daily eating duration (by 13%), and a higher total daily DMI (by 7.2%) in the EXP cows as compared with the CON cows. The in vivo DM and NDF digestibility was higher by 4.9 and 22.7%, respectively, in the EXP cows than in the CON cows. The rumination time for the TMR in the EXP cows was 12.7% (54.3 min/d) shorter than in the CON cows, and this was probably related to the difference of 12.4% in physically effective NDF intake between the 2 groups. Patterns of daily rumination and feed consumption throughout an average day showed a delay of approximately 1 to 2 h between the eating and rumination peaks. Particle flow from the rumen of the EXP cows was characterized by a longer rumen mean retention time (by 17.8%) and longer rumination time per kilogram of roughage ingested (by 23.5%) as compared with the CON cows. Thus, favorable conditions for NDF digestion were created in the rumen of the EXP cows, as reflected in their rumen pH values (6.67). The advantage of the EXP cows in intake and digestibility was reflected in a concomitant increase of 7.4% in milk production and of 9.2% in FCM yield as compared with the CON cows. No difference was found between the 2 groups with respect to efficiency of feed utilization for milk production and BW changes.     

甘肃省有机肥资源分布与利用潜力

通过调查研究和测定分析,甘肃省有机肥资源总量是13405.3万吨,有机肥利用量5846.43万吨,利用率为43.6%,且品种全,富含氮、磷、钾养分。人畜粪尿、作物秸秆、绿肥、饼肥四种肥源贡献N,P2O5,K2O养分总量达到204.36万吨,是1999年甘肃省化肥施用量的63.4万吨的3.22倍,重视有机肥养分资源的再循环利用,有利于农业的可持续发展。     

复(混)肥尿素磷铵、氯磷铵的肥效与施用技术

据省内17个田间试验点统计,水稻施氯磷铵处理平均亩产488公斤,比尿素磷铵447公斤增产9.2％,比尿素 普钙458.2公斤增产6.5％。在棕壤、草甸土上,氯磷铵对玉米、谷子、棉花和大豆等作物的肥效同尿素磷铵及等养分的单质配合肥大体相等。在中等肥力条件下,氯磷铵对玉米、大豆经济效益最佳施肥量分别为24.7公斤/亩和16.4公斤/亩;对水稻作物在高、中、低三种肥力水平条件下最佳施肥量分别为26.6公斤/亩,45.5公斤/亩和57.8公斤/亩.在粮食作物上,采用氮磷比为 1:1型的复合肥应以50％作基肥.再用50％的单质氮素作追肥经济效益最高。在施用方法上复合肥以作基肥深施和全层施肥效果好,分别比对照增产49.6％和39.1％。     

Short communication: reference values for blood parameters in Holstein dairy cows: effects of parity, stage of lactation, and season of production

Confidence intervals for blood parameters used for nutritional and metabolic profile testing in cattle were calculated for clinically normal lactating Holstein cows, taking into account the effects of parity, stage of lactation, and season. Blood samples were collected from 740 cows in 33 Italian dairy herds according to a predefined protocol. Herds were visited during summer and the following winter, sampling 12 lactating cows at each visit (4 primiparous and 8 multiparous). Six cows were selected from the early-lactation group (days in milk: 10 to 89) and the other 6 were selected from the mid-lactation group (days in milk: 90 to 215). Cow selection criteria excluded animals clinically exposed to periparturient diseases as well as animals not considered in good health by a veterinary clinical examination. For each blood variable, outliers were identified and discarded. Data were then analyzed for their Gaussian distribution and variables with not normal distribution were log-transformed to adjust for lack of normality. Herd mean values were calculated for each blood parameter according to 3 main classification factors: parity (primiparous vs. multiparous), stage of lactation (early vs. mid) and season of production (summer vs. winter). The resulting data set was statistically analyzed using a mixed model with the fixed effects of these factors, their interactions, and the random effect of herd. General 95% confidence intervals were calculated for blood variables that showed a relevant herd variance component such as albumin, triglycerides, aspartate, urea, glucose, alanine aminotransferase, lactate dehydrogenase, direct and total bilirubin, calcium, magnesium, and potassium. For the remaining parameters, specific confidence intervals were calculated for each level of the significant main factors. Parity affected blood concentration of total protein, globulin, creatinine, alkaline phosphatase, gamma glutamyl transferase, creatinine kinase, and phosphorus. Blood nonesterified fatty acids, aspartate aminotransferase, gamma glutamyl transferase, creatinine kinase and cholesterol were influenced by stage of lactation. The season of production had a significant effect on total protein, globulin, creatinine, alkaline phosphatase, phosphorus, sodium, and chlorine. The outcomes of this work will improve the accuracy of the biochemical profile as a tool for dairy practitioners to assess the metabolic status of lactating Holstein cows.     

新型有机肥的氮素在土壤中的转化及其对草莓生长和品质的影响

土壤中硝态氮和铵态氮的含量直接影响着作物的生长和品质。通过田间试验研究了不同有机肥料氮素在土壤中的转化及其对草莓生长和果实品质的影响。结果表明,施用有机肥可以提高草莓苗期土壤硝态氮的比例,硝铵比值大于尿素处理,同时有机肥处理硝铵比值从苗期至盛花期呈下降趋势,但尿素处理则表现为上升的趋势,而花序现蕾期土壤硝铵比的降低,有利于植株花蕾的形成,因此土壤硝铵比值的变化趋势一定程度上决定着草莓的产量和品质。在等量施用氮素养分的条件下,施用有机肥料均较尿素更能促进草莓生长发育和增加草莓产量。施用有机肥对草莓品质的改善作用也优于尿素,果实中糖/酸比值较无肥区提高23.7%-28.7%,较尿素区提高16.5%-21.2%。     

Net flux of nutrients across the rumen wall of lactating dairy cows as influenced by dietary supplements of folic acid

The objective of the present study was to determine whether a dietary supplementation of folic acid, at levels used in our previous studies, would affect ruminal fermentation and the net flux of nutrients across the rumen wall of lactating dairy cows. Approximately 4 wk after calving, 5 lactating multiparous cows were surgically equipped with a ruminal cannula, an ultrasonic flow probe around the right ruminal artery, and indwelling catheters in the right ruminal vein and the ileocolic artery. Cows were fed a total mixed ration served in 7 equal meals per d (i.e., every 3.4 h). The experimental design was an unbalanced crossover arrangement with 3 periods of 4 wk each. The vitamin supplement, incorporated in equal amounts into each meal, was supplied at 0, 3, or 6 mg of folic acid per kg of BW per d. During the last week of each experimental period, blood samples were taken simultaneously from the 2 catheters every 30 min and rumen fluid was collected every 60 min during 2 consecutive meal intervals. Dietary supplementation with folic acid had no effect on milk production (27.2 ± 1.3 kg/d) or DMI (19.9 ± 0.7 kg/d), but milk concentrations and yields of total solids, fat, and protein increased linearly with increasing doses of folic acid ingested. Concentrations of folates in rumen fluid and arterial plasma, averaged over time, increased linearly with the dose of folic acid ingested but the net flux of folates across the rumen wall was not different from zero. Concentrations of butyrate in ruminal fluid decreased quadratically with the daily supply in folic acid. Dietary supplements of folic acid had no effect on pH and osmolality of ruminal fluid, nor on ruminal concentrations of lactate, ammonia, acetate, or propionate, total VFA, or microbial counts. The uptake of urea-N by the rumen wall tended to increase quadratically with the dose ingested but net fluxes of other nutrients were not affected by treatments. These results suggest that the effects of folic acid supplements on lactational performance cannot be explained by effects on rumen metabolism.