Heritability of intramammary infections at first parturition and relationships with sire transmitting abilities for somatic cell score,udder type traits,productive life,and protein yield

The objective of this study was to determine the relationships among daughter intramammary infections at first parturition and sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield. Quarter milk samples from 958 daughters (in eight Pennsylvania herds and one Nebraska herd) of 182 Holstein sires were collected within a few days of first calving and cultured to determine intramammary infection status. A total of 446 cows had intramammary infections in 835 quarters at first parturition. Incidence of intramammary infections at first parturition and the proportion of quarters infected per cow were regressed on age at first calving, days in milk at sample collection, herd-season of calving (a classification variable), and sire transmitting abilities taken one at a time. Linear effects, non-linear effects, and odds ratios were estimated for sire transmitting abilities. Separate, preplanned analyses were conducted on data from one herd that gave all heifers an intramammary antibiotic infusion in each quarter 30 d prior to the expected calving date. Separate analyses were also conducted on dependent variables that considered intramammary infections at first parturition from: all organisms, coagulase-negative staphylococci, coliform species, streptococci other than Streptococcus agalactiae, and the most common environmental organisms (coliform species and streptococci other than Streptococcus agalactiae). Daughters of sires that transmit the lowest somatic cell score had the fewest intramammary infections at first parturition. Daughters of sires that transmit longer productive life, shorter teats, and closely spaced front teats had fewer intramammary infections at first parturition. Selection for lower somatic cell score, longer productive life, shorter teats, or closely spaced front teats may reduce the incidence of intramammary infections at first parturition.     

Sensitivity and specificity of a tail-activity measuring device for calving prediction in dairy cattle

Efficient calving surveillance is essential for avoiding stillbirth due to unattended dystocia. Calving sensors can help detect the onset of parturition and thus ensure timely calving assistance if necessary. Tail-raising is an indicator of imminent calving. The objective of this study was to evaluate a tail-mounted inclinometer sensor (Moocall Ltd., Dublin, Ireland) and to monitor skin integrity after sensor attachment. Cows (n = 157) and heifers (n = 23) were enrolled at 275 d post insemination, and a sensor was attached to each cow's tail. Investigators checked for signs indicating the onset of stage II of parturition, verified the position of the sensor, and evaluated the skin integrity of the tail above and below the sensor hourly for 24 h/d. We used 5 different intervals (i.e., 1, 2, 4, 12, and 24 h until calving) to calculate sensitivity and specificity. Sensors continuously remained on the tail (i.e., within 3 cm of the initial attachment position) after initial attachment until the onset of calving in only 13.9% of animals (n = 25). Sensors were reattached until a calving event occurred (51.6%) or the animal was excluded for other reasons (34.4%). In 31 animals the sensor was removed because the tail was swollen or painful. Heifers were significantly less likely than cows to lose a sensor but more likely to experience tail swelling or pain. Depending on the interval preceding the onset of parturition, sensitivity varied from 19 to 75% and specificity from 63 to 96%.     

The effect of stocking density and a blind on the behavior of Holstein dairy cattle in group maternity pens. Part I: Calving location,locomotion, and separation behavior

In a more natural setting, dairy cows separate from herdmates and seek a secluded area to give birth. However, on many dairy facilities, cows calve in barren group pens with limited space, which may limit their ability to perform these behaviors. The objective of this study was to determine the effect of stocking density and provision of a blind (a single-sided solid partition) in group bedded pack maternity pens on the behavior of dairy cattle. The study included 4 experimental treatments: (1) high stocking density (7.7–12.9 m² of lying space/cow) with a blind, (2) low stocking density (15.4–25.8 m²) with a blind, (3) high stocking density without a blind, and (4) low stocking density without a blind. We analyzed the effect of these treatments on locomotor and separation behavior as well as blind use during the 24 h before calving. A total of 127 primiparous heifers and 247 multiparous cows were housed in 16 mixed-parity groups (4 groups per treatment) from approximately 3 wk before to immediately after calving. Locomotor behavior increased from 24 to 2 h before calving regardless of treatment but increased the most in high stocking density pens without a blind. Additionally, heifers performed more locomotion than cows. Animals increased their distance from other cows beginning approximately 4 h before calving. Animals in low stocking density pens had a greater distance from other cows compared with those in high stocking density pens. Additionally, heifers had a greater distance from penmates during the 4 h before calving than cows. More animals calved in the area of the pen that contained a blind compared with the same respective areas of high and low stocking density pens that did not contain a blind. These results suggest that periparturient dairy cattle in group maternity pens are motivated to seek seclusion at calving, but increased stocking density may impede their ability to do so. Providing additional space and a blind may benefit periparturient dairy cows and heifers by facilitating natural calving behaviors.     

Short communication: Calving site selection of multiparous,group-housed dairy cows is influenced by site of a previous calving

A calving cow and her newborn calf appear to have an attracting effect on periparturient cows, which may potentially influence the functionality of future motivation-based calving pen designs. In this pilot study we examined whether calving site selection of group-housed Holstein dairy cows was affected by the site of a previous calving. Ten multiparous cows moved to 1 of 2 group pens 11 (range = 4–27) d before calving were included. Each pen consisted of an open area (9 × 9 m) connected to 6 secluded areas (4.5 × 3 m each), where cows could move freely between all areas. Time of calving, location of the breaking of the amniotic sac, as well as the place of birth were recorded. In all but 1 case cows calved within a distance of 1 cow length from where the previous calving took place, suggesting that the cows did not select calving site at random. These preliminary observations indicate that choice of calving site may be affected by the site of a previous calving, potentially explained by the presence of amniotic fluids.     

医用气体(50%O2与50%N2O)的生产与管理

通过对医用气体的原料气医用氧与医用笑气混合生产过程，最终产品质量检验，医院临床使用的控制，使产妇减轻疼痛并保证妇婴安全。     

Carryover effects of potassium supplementation on calcium homeostasis in dairy cows at parturition

The purpose of this study was to test whether supplementation with K improves bone mineral density (BMD) in older cows so that by parturition their bone is better able to mobilize Ca. Twenty-four Holstein Friesian cows (6 mo pregnant, lactating, and in their third or later lactation) were allocated to 2 equal groups and individually fed twice daily a total diet comprising low K oaten hay plus a pelleted concentrate fortified with or without K₂CO₃ to achieve 3.12% K/kg of DM in the total diet of the K-supplemented (KS) cows compared with 1.50% K/kg of DM for the control cows. The cows were fed their respective diets from the beginning of their sixth month of pregnancy until 2 wk before the expected date of parturition. The strategy was to use K to stimulate a mild increase in extracellular pH to potentially improve BMD well before parturition, when high K contents in the diet are considered safe, but cease supplementing in the few weeks prepartum, when high intakes of K are known to be problematic. The expectation was that the effect of the denser bone would carry through to benefit the cow's plasma Ca, P, and Mg status at parturition. Prior to the period of K supplementation, the cows were part of a commercial pasture-based herd, to which they were returned at the end of the supplementation period and treated as 1 group from at least 11 d prepartum until the end of the study at d 42 of the next lactation. Supplementation with K successfully induced a sustained increase of urinary pH throughout late lactation and into the dry period, as expected. The KS cows consistently averaged a urine pH 0.25 ± 0.10 U higher than the controls. However, there was no significant effect of K supplementation on BMD, bone mineral concentrations, plasma osteocalcin, urinary deoxypyridinoline:creatinine plasma Ca, or plasma P concentrations during or immediately after the cessation of supplementation, nor where there any carryover effects during parturition or by d 42 of lactation. Instead, there was an unexpected decrease in the concentration of Mg in plasma of the KS cows compared with the control cows that extended from 0.5 to 2.5 d postpartum. The timing of the decline in plasma Mg was paralleled by declines in plasma concentrations of 1,25 dihydroxy-vitamin D₃ and urinary excretion of Ca and Mg, whereas urinary excretion of P increased; all changes were consistent with a hypomagnesemia that could increase the risk of hypocalcemia. These data suggest that, in addition to the well-documented negative effects of K when fed immediately at parturition, the effects of high dietary K diets can carry over for at least 11 d to trigger a mild hypomagnesemia at parturition. Because K supplementation did not improve BMD prepartum, it was not possible to conclude for or against an ability of denser bone to reduce the risk of hypocalcemia in older cows at parturition.     

ADSA Foundation Scholar Award: What makes for a good life for transition dairy cows? Current research and future directions

Dairy cows experience several challenges during the transition period, historically defined as the 3 wk before to 3 wk after calving. During this 6-wk window, cows undergo a series of social, nutritional, and physical changes that affect their quality of life. Cows are also at the highest risk of becoming ill in the days and weeks after calving compared with any other period in their adult life. Because of this, the transition cow has been a central focus of dairy cattle research for at least the last 50 yr, with much of this work targeted at identifying, treating, and preventing postpartum disease. However, understanding what makes for a good life for transition cows requires consideration of more than just their health. When considering a cow's welfare, we must also include her emotional experiences and ability to live a reasonably natural life. To gain a broader perspective on the welfare of transition cows that goes beyond their health, continued inter- and transdisciplinary approaches are needed. The aims of this narrative review are to (1) describe a framework used to study animal welfare, which includes different perspectives on what makes for a good life for animals using examples from transition cow research, (2) summarize the advancements we have made in developing our understanding of the welfare of transition dairy cows over the last several decades, (3) identify gaps in the literature and propose new and continued topics for research, and (4) suggest a path forward for researchers, including the use of methods from both the natural and social sciences to rethink existing problems, understanding barriers to adoption of evidence-based practice, and prepare for future challenges.