The relationship between responsiveness of first-lactation heifers to humans and the behavioral response to milking and milk production measures

The human–animal relationship can influence how an animal responds to situations involving humans and affect animal well-being and production. The objectives of this research were to (1) determine if there is a relationship between the behavioral reactivity of New Zealand dairy heifers toward humans and the behavioral response to cluster placement during milking and milk production measures and (2) determine if this relationship changes as heifers become habituated to the milking process. A total of 150 primiparous heifers were randomly selected from 3 commercial dairy farms. Approximately 1 month before calving, 2 behavioral tests, avoidance distance in response to an approaching human and exit speed from a restraint, were performed on 50 heifers at each farm. For each heifer, behavioral observations were recorded during the morning milking period (during the first and sixth weeks of lactation). Behaviors recorded during cluster placement at milking included flinching, stepping, and/or kicking (FSK). Milk yields, milking durations, and average milk flow rates were recorded for each individual heifer during the first and sixth weeks of lactation. Avoidance distance and exit speed were positively correlated (P < 0.001). The FSK response during cluster placement was negatively (P < 0.01) correlated with exit speed during week 6 of lactation, but there was no relationship (P > 0.05) between avoidance distance and FSK. Avoidance distance was positively (P < 0.005) correlated with milk flow rates during weeks 1 and 6 of lactation and milk yields (P < 0.01) during week 6 of lactation. However, there was no relationship (P > 0.05) between exit speed and milk yields, durations, or flow rates. Furthermore, the FSK response was negatively (P < 0.05) correlated with milk yield during weeks 1 and 6 of lactation. Therefore, the behavioral response of heifers toward humans and the milking process appears to be related to milk production measures.     

Associations between pregnancy outcome and serological response to Neospora caninum among a group of dairy heifers

AIM: To monitor pregnancy in a group of rising 2-year-old dairy heifers on a farm on which abortion due to Neospora caninum was known to occur in previous years.

METHODS: A prospective cohort study group of 164 rising 2-year-old heifers was pregnancy-tested and blood-sampled at 4–5-week intervals throughout gestation. Sera were tested for antibodies to N. caninum at 3–4-month intervals, using an enzyme-linked immunosorbent assay (ELISA). When loss of pregnancy was detected, an N. caninum indirect fluorescent antibody test (IFAT) was conducted retrospectively on stored sera collected the month before abortion, the month abortion was detected, and for the following 2 months, from heifers that aborted. All fetal and placental material detected following abortion was subjected to gross post-mortem and histopathological examination.

RESULTS: Eleven of 18 (61%) heifers that were seropositive and 4/146 (3%) heifers that were seronegative to N. caninum by ELISA, aborted. The relative risk for abortion among ELISApositive heifers was 23.6. Abortion occurred predominantly between Days 120 and 152 gestation among the ELISA-positive heifers and throughout gestation among the ELISA-negative heifers. IFAT titres rose around the time of abortion in most of the heifers that were previously seropositive by ELISA, but dropped rapidly again in post-abortion samples. IFAT titres among 4/6 ELISA-positive heifers that did not abort increased, but later in gestation than the time other heifers aborted. IFAT titres remained negative in heifers that aborted that were ELISAnegative.

CONCLUSIONS: Heifers that were seropositive to N. caninum by ELISA had a much greater risk of abortion than seronegative heifers. Most seropositive heifers showed evidence of a reactivation of infection during pregnancy. High (≥1:2,000) N. caninum IFAT titres also occurred in non-aborting heifers.

CLINICAL RELEVANCE: Culling of replacement heifers seropositive to N. caninum may be a cost-effective strategy for minimising risk of abortion. Pregnancy testing heifers before 5 months gestation may overestimate the number that calve in N. caninum-infected herds, but would assist in documenting the occurrence of abortion. Reliance on a high (>1:2,000) IFAT titre to rule-in N. caninum as a cause of abortion is likely to produce false-positive results.     

马头山羊与本地山羊补饲育肥对比试验

对农不同品种山羊进行补饲育肥对比试验，结果表明，在牧草旺盛时节补饲，晶增重公羊高于母羊，马头山羊高于本地山羊，尤其是本地母山羊日增重明显地低于本地公山羊及马头山羊母羊（P＜0．05），极显著低于马头山羊公羊（P＜0．01）；本地公山羊日增重也显著低于马头山羊公羊（P＜0．05），同马头山羊母羊间没有差别（P＞0．05）。在牧草枯衰时节补饲，日增重公羊仍高于母羊，本地母山羊同本地公山羊间没有显著差异（P＞0．05），但仍同马头山羊母羊间存在明显差别（P＜0．05）；本地公山羊同马头山羊母羊间没有差异（P＞0．05），但与马头山羊公羊间存在差异（P＜0．05）。在屠宰率、净肉率上4组间没有明显差别（P＞0．05）。经济效益马头山羊优于本地山羊，公羊优于母羊。     

Effects of type of forage fed to dairy heifers: associations between claw characteristics, clinical lameness, environment and behaviour

Heifers were reared separately on wet fermented (WF) (grass silage based) or dry unfermented (DU) (straw based) diets. Clinical lameness was recorded and physical claw attributes were measured regularly, up to six months after calving at approximately two years of age. Two months before calving, some aspects of animal behaviour and the properties of slurry were studied. The incidence of lameness due to claw horn lesions was significantly higher (P < 0.01) in WF than in DU. WF suffered more serious heel erosion prior to calving (P < 0.05) and had softer claw horn at two (heel and axial sole) out of five sites throughout (P < 0.01 and P < 0.05). The slurry produced by WF had lower total solids content (P < 0.05) and viscosity (P < 0.001). WF spent longer standing and feeding (P < 0.001). It is proposed that standing for longer in less viscous slurry contributed to softer claw horn and more severe heel erosion, predisposing WF to claw horn lesions causing lameness. Reducing contact with low dry matter slurry is recommended for improving claw health.     

An Investigation of the Ability of the Glutaraldehyde Test to Distinguish between Acute and Chronic Inflammatory Disease in Horses

The Glutaraldehyde test (GT), a rapid and inexpensive test, has been utilized empirically for many years in bovine practice for diagnosing inflammatory diseases. GT is used primarily to demonstrate increased serum concentrations of fibrinogen and globulin. Glutaraldehyde binds with free amino groups in fibrinogen and immunoglobulin to create a clot in a first degree chemical reaction. The clotting time of the GT estimates the content of proteins produced in response to inflammation. The applicability of GT for diagnosing inflammation in the horse has never been investigated. The objective of this study was to determine the ability of GT to distinguish between acute and chronic inflammatory disease in horses. Thirty-seven horses with suspected inflammatory diseases were evaluated using the GT, history, complete clinical examination and routine blood analysis. GT-times, laboratory results and clinical outcome were compared statistically. Horses that were determined to be acutely affected (based on history, clinical examination and routine blood analysis) tended to have a negative GT (75%). Results of the GT did not correlate with blood fibrinogen concentration. Positive GT also predicted a fatal outcome in 69% of the clinical cases. The results of this trial indicate that GT can be a useful screening test to distinguish between acute and chronic inflammatory disease in horses.     

Feeding corn distillers grains as an energy source to gestating and lactating beef heifers: Impact of excess protein on feedlot performance,glucose tolerance,carcass characteristics and Longissimus muscle fatty acid profile of steer progeny

This study was conducted to determine the impact of dried distiller's grain with solubles (DDGS) from 192 days of gestation through 118 days of lactation on feedlot performance, carcass characteristics, Longissimus muscle (LM) fatty acids and glucose tolerance of male progeny (n = 36). Angus‐Simmental heifer dams were fed diets that contained either DDGS (DG) or not (CON) formulated to provide similar daily net energy for gain but differing crude protein. In the feedlot, male progeny were fed a diet devoid of DDGS. An intravenous glucose tolerance test (IVGTT) was performed on a subset of 20 steers prior to harvest. Steers were harvested at a common 12th rib fat depth. Data were analyzed with the GLIMMIX and MIXED procedures of SAS. Performance (P ≥ 0.11) and glucose and insulin concentrations during IVGTT (P ≥ 0.24) did not differ between treatments. Dressing percentage tended to be greater (P = 0.09) in DG than CON progeny, but all other carcass characteristics did not differ (P ≥ 0.18). Progeny from DG dams had greater LM 16:2, 18:0, and 20:1 n‐9 concentrations than progeny from CON dams (P ≤ 0.02). In conclusion, DDGS are a viable option for gestating and lactating beef cows.     

Diagnosis of Canine Brucellosis: Comparison between Serological and Microbiological Tests and a PCR Based on Primers to 16S-23S rDNA Interspacer

A pair of primers directed to 16S-23S rDNA interspacer (ITS) was designed directed to Brucella genetic sequences in order to develop a polymerase chain reaction (PCR) putatively capable of amplifying DNA from any Brucella species. Nucleic acid extracts from whole-blood from naive dogs were spiked with decreasing amounts of Brucella canis RM6/66 DNA and the resulting solutions were tested by PCR. In addition, the ability of PCR to amplify Brucella spp. genetic sequences from naturally infected dogs was evaluated using 210 whole-blood samples of dogs from 19 kennels. The whole-blood samples collected were subjected to blood culture and PCR. Serodiagnosis was performed using the rapid slide agglutination test with and without 2-mercaptoethanol. The DNA from whole blood was extracted using proteinase-K, sodium dodecyl sulphate and cetyl trimethyl ammonium bromide followed by phenol–chloroform purification. The PCR was capable of detecting as little as 3.8 fg of Brucella DNA mixed with 450 ng of host DNA. Theoretically, 3.8 fg of Brucella DNA represents the total genomic mass of fewer than two bacterial cells. The PCR diagnostic sensitivity and specificity were 100%. From the results observed in the present study, we conclude that PCR could be used as confirmatory test for diagnosis of B. canis infection.     

Different prostaglandin F2α secretion in response to oxytocin injection between pregnant and non‐pregnant cows: effect of the day of oxytocin challenge test for determining the difference

The present study was conducted to determine the difference in plasma prostaglandin F₂α metabolite concentrations following oxytocin (OT) challenge between pregnant and non‐pregnant cows. Experiment 1: cows were subjected to the OT challenge test on days 12, 14 or 16 (day of estrus = day 0) with or without prior insemination and plasma 13,14‐dihydro‐15‐keto prostaglandin F₂α (PGFM) concentrations were measured from ?30 to 180 min after OT injection. On day 16, the increment of plasma PGFM concentrations in response to OT injection was significantly smaller in pregnant than that in cyclic cows. On days 12 and 14, there was little OT‐induced PGFM secretion and no difference in PGFM increase between the pregnant and cyclic cows. Experiment 2: cows were inseminated on day 0 and subjected to the OT challenge test on day 16. Cows were classified into non‐pregnant/early embryonic death (NP/EED), late embryonic death (LED) and pregnant (PREG) groups. The increment of PGFM concentrations in response to OT injection was less in both PREG and LED groups than that in the NP/EED group. In conclusion, plasma PGFM secretion induced by OT is suggested as the base of pregnancy diagnosis prior to returning estrus in cows.