Post-calving Period Research Articles

Effect of dry cow therapy on incidence of clinical mastitis,milk yield and composition in crossbred cows

Mastitis is considered as one of the important production disease in dairy cows which incurs huge economic losses to dairy industry, despite considerable efforts has been dedicated to solve it for the last two decades. In the present study, the impact of dry cow therapy (DCT) on incidence of clinical mastitis, milk yield and composition in crossbred cows was studied. About 20 healthy crossbred cows were selected at dry-off and randomly allotted either to control or treatment group. Daily milk yield of cows was recorded up to 45 days post-partum and fortnightly separate quarter wise milk samples were collected for estimation of milk composition. While no quarter in the treatment group showed clinical mastitis, 33.33% of quarters in control group showed clinical mastitis within 45 days post-partum. Milk production increased by 9.71, 8.40 and 18.18% during first, second and third fortnight with overall value 11.84% during the entire 45 days post-calving period in DCT treated cows compared to control group. Also, the overall fat-corrected milk, solid-corrected milk and energy-corrected milk production following 45 days post-partum increased significantly (P<0.05) by 22.71, 23.70 and 22.80%, respectively in treated group than control group. However, overall mean milk components such as fat, protein, lactose, SNF and TS remained similar between treatment and control groups. Taken together, the above results indicated that DCT increased milk yield by reducing incidence of clinical mastitis during early lactation.

Identification of predictive biomarkers of disease state in transition dairy cows

In dairy cows, periparturient disease states, such as metritis, mastitis, and laminitis, are leading to increasingly significant economic losses for the dairy industry. Treatments for these pathologies are often expensive, ineffective, or not cost-efficient, leading to production losses, high veterinary bills, or early culling of the cows. Early diagnosis or detection of these conditions before they manifest themselves could lower their incidence, level of morbidity, and the associated economic losses. In an effort to identify predictive biomarkers for postpartum or periparturient disease states in dairy cows, we undertook a cross-sectional and longitudinal metabolomics study to look at plasma metabolite levels of dairy cows during the transition period, before and after becoming ill with postpartum diseases. Specifically we employed a targeted quantitative metabolomics approach that uses direct flow injection mass spectrometry to track the metabolite changes in 120 different plasma metabolites. Blood plasma samples were collected from 12 dairy cows at 4 time points during the transition period (−4 and −1wk before and 1 and 4wk after parturition). Out of the 12 cows studied, 6 developed multiple periparturient disorders in the postcalving period, whereas the other 6 remained healthy during the entire experimental period. Multivariate data analysis (principal component analysis and partial least squares discriminant analysis) revealed a clear separation between healthy controls and diseased cows at all 4 time points. This analysis allowed us to identify several metabolites most responsible for separating the 2 groups, especially before parturition and the start of any postpartum disease. Three metabolites, carnitine, propionyl carnitine, and lysophosphatidylcholine acyl C14:0, were significantly elevated in diseased cows as compared with healthy controls as early as 4wk before parturition, whereas 2 metabolites, phosphatidylcholine acyl-alkyl C42:4 and phosphatidylcholine diacyl C42:6, could be used to discriminate healthy controls from diseased cows 1wk before parturition. A 3-metabolite plasma biomarker profile was developed that could predict which cows would develop periparturient diseases, up to 4wk before clinical symptoms appearing, with a sensitivity of 87% and a specificity of 85%. This is the first report showing that periparturient diseases can be predicted in dairy cattle before their development using a multimetabolite biomarker model. Further research is warranted to validate these potential predictive biomarkers.

A Connection Between Mastitis During Early Lactation and Reproductive Performance of Dairy Cows – A Review / Związek mastitis we wczesnej laktacji z użytkowością reprodukcyjną krów mlecznych – artykuł przeglądowy

Abstract The objective of this study was to present a relationship between mastitis in the post-calving period and fertility traits of dairy cows. The threshold of 200,000 cells/ml for somatic cell count is used as a reference for healthy quarters of the cow’s udder. The genetic correlation between mastitis and somatic cell count is strong (from 0.7 to 0.8). Although heritability for fertility traits is low (from 0.01 to 0.02), the genetic standard deviation for mastitis varies from 1.2 to 7.0 percentage units, suggesting that genetic gain can be achieved by selecting for mastitis. Results of this study suggest that mastitis in the postpartum period can have a markedly negative impact on the reproductive performance of dairy cows. The synergistic effect of common conditions (somatic cell count, body condition score and lameness score) or other factors (e.g. heat stress, fertility management, the presence of repeat breeders) also lowers fertility of cows. Production of milk with fewer than 100,000 cells/ml leads to improved health and fertility in the cows.

Does housing nulliparous dairy cows with multiparous animals prior to calving influence welfare- and production-related parameters after calving?

The aim of this experiment was to determine the effects of housing nulliparous cows with non-lactating multiparous cows during the pre-calving period, on welfare and production-related parameters during the post calving period. Twenty nulliparous Holstein Friesian dairy cattle were assigned to one of two treatments (‘Mixed and Unmixed’) pre-calving. The ‘Mixed’ treatment involved housing experimental animals with non-lactating multiparous cows for three weeks prior to their expected calving date. In the ‘Unmixed’ treatment, experimental animals were housed with other nulliparous animals during the 3-wk period prior to their expected calving date. During this pre-calving period animals in both treatments were housed in groups of 10 animals, with the ‘Mixed’ group comprising of seven multiparous non-lactating cows and three experimental primiparous cows. The experimental animals were added to a resident group that contained 15 animals (10 multiparous cows and 5 primiparous cows) within 24h of calving. The behaviour of the experimental animals was assessed immediately after the mixing period and also after feeding during the first month after introduction to the resident group (days 2, 4, 10, and 1 day in wks 3 and 4). In addition, data loggers were attached to the animals for a 24h period on five occasions during the first month after calving to assess lying behaviour. Lying location and synchronicity of lying with the rest of the group was assessed by direct observation on two consecutive days each wk during the 2-h period prior to evening milking. Milk production, serum cortisol levels and changes in body condition and live weight were assessed during the first month after calving. ‘Mixed’ animals received fewer butts (P<0.05) after mixing, and these animals also showed increased locomotion during this period (P<0.05). After feeding, ‘Mixed’ animals performed more ‘shouldering’ of other animals and increased locomotion (P<0.05), and received fewer butts (P<0.001). Also during this period animals in the ‘Unmixed’ treatment were located in the cubicles to a greater extent (P<0.01). Animals in the ‘Mixed’ treatment were located to a greater extent in the front passage after feeding (P<0.001). During observations prior to evening milking, both treatment groups were located in the rear passage significantly more than resident cows (P<0.05). No significant treatment effects were shown for milk yield, serum cortisol levels or body weight or condition score loss. Overall, giving primiparous cows experience with dry multiparous cows prior to calving appeared to improve their welfare when mixed into a group containing older animals after calving through leading to lower levels of received aggression. It is suggested that the increased levels of aggression and locomotion performed by these animals, and the increased time spent near the front feeding passage after feeding, reflected increased ‘confidence’ in ‘Mixed’ animals.

Using non-steroidal anti-inflammatory drugs around calving: Maximizing comfort, productivity and fertility

Non-steroidal anti-inflammatory drugs (NSAIDs) have analgesic, anti-inflammatory, anti-endotoxic and anti-pyretic effects in cattle. As such, they could be expected to have significant effects in cows and calves in the post-calving period. This review evaluates the published data on the use of NSAIDs in the dam and its calf after dystocia, the impact of NSAIDs on uterine involution, the restoration of ovarian function and prevention and treatment of the metritis complex, and the benefits of using NSAIDs in the recumbent cow. Overall, the published data are very limited, despite frequent use of NSAIDs by veterinarians in the post-calving cow, and the small number of published studies focus on blanket treatment of calving cows rather than targeted treatment after dystocia. Blanket treatment had no economic benefit; indeed, some studies reported adverse effects, such as pyrexia and increased risk of metritis. There is even less information on the value of treating calves with NSAIDs after dystocia, despite significant tissue damage which may benefit from NSAID use. Appreciably more studies have evaluated the influence of NSAIDs on uterine and ovarian function, but clinical relevance is limited. In cows with a normal puerperium, prolonged treatment with NSAIDs may slow the restoration of normal function, but most reported studies are small and use NSAIDs more frequently and for longer periods than is common in general practice. The evidence of a clinical benefit in cows with puerperal disease is limited and equivocal, and the evidence base for the use of NSAIDs in the treatment of recumbent cows is also small, even though an expert panel concluded that NSAIDs were a key aspect of veterinary treatment of downer cows. The lack of evidence identified by this review supports the contention that NSAIDs are likely to be under-used and sub-optimally prescribed in the post calving period. Further research on the use of NSAIDs in the post-calving cow and calf is required.

An evaluation of the effect of altering nutrition and nutritional strategies in early lactation on reproductive performance and estrous behavior of high-yielding Holstein-Friesian dairy cows

Reproductive performance in the high-yielding dairy cow has severely decreased in the last 40 yr. The aim of this study was to compare the effectiveness of 4 nutritional strategies in improving the reproductive performance of high-yielding dairy cows. It was hypothesized that offering cows a high-starch ration in early lactation would enhance the onset of luteal activity, and that decreasing the severity of negative energy balance in the early postcalving period would improve reproductive parameters. Nutritional regimens aimed at improving fertility were applied to 96 Holstein-Friesian dairy animals. Upon calving, animals were allocated in a balanced manner to one of 4 dietary treatments. Primiparous animals were balanced according to live weight, body condition score and calving date. Multiparous animals were balanced according to parity, previous lactation milk yield, liveweight, body condition score and calving date. Treatment 1 was based on an industry best practice diet (control) to contain 170g of crude protein/kg of dry matter. Treatment 2 was an individual cow feeding strategy, whereby the energy balance (EB) of individual animals was managed so as to achieve a predetermined target daily EB profile (±10MJ/d). Treatment 3 was a high-starch/high-fat combination treatment, whereby an insulinogenic (high-starch) diet was offered in early lactation to encourage cyclicity and followed by a lipogenic (low-starch, high-fat) diet to promote embryo development. Treatment 4 was a low-protein diet, containing 140g of crude protein/kg of dry matter, supplemented with protected methionine at an inclusion level of 40g per animal per day. The nutritional strategies implemented in this study had no statistically significant effects on cow fertility measures, which included the onset of luteal activity, conception rate, in-calf rate, and the incidence of atypical cycles. The individual cow feeding strategy improved EB in early lactation but had no benefit on conception rate to first insemination. However, conception rate to second insemination, 100-d pregnancy rate (from the commencement of breeding), and overall pregnancy rate tended to be higher in this group. The high-starch/high-fat treatment tended to decrease the proportion of delayed ovulations and increase the proportion of animals cycling by d 50 postcalving. Animals that failed to conceive to first insemination had a significantly longer luteal phase in the first cycle postpartum and a longer inter-ovulatory interval in the second cycle postpartum. With regards to estrous behavior, results indicate that as the size of the sexually active group increased, the intensity of estrus and the expression of mounting or attempting to mount another cow also increased. Furthermore, cows that became pregnant displayed more intense estrous behavior than cows that failed to become pregnant.

Rumen pH and fermentation characteristics in dairy cows supplemented with Megasphaera elsdenii NCIMB 41125 in early lactation

This study investigated the effect of using the lactate-utilizing bacterium Megasphaera elsdenii NCIMB 41125 as a probiotic supplement on rumen fermentation and pH in dairy cows in the immediate postcalving period. Fourteen multiparous rumen-fistulated Holstein cows, blocked according to 305-d milk yield in the previous lactation, were used in a randomized complete block design. From d 1 to 28 postcalving, cows were fed ad libitum a total mixed ration with a forage to concentrate ratio of 392:608 and a starch concentration of 299g/kg of dry matter. Treatments consisting of a minimum of 1010 cfu of Megasphaera elsdenii NCIMB 41125 or autoclaved M. elsdenii (placebo) were administered via the rumen cannula on d 3 and 12 of lactation (n=7 per treatment). Mid-rumen pH was measured every 15min, and eating and ruminating behaviors were recorded for 24h on d 2, 4, 6, 8, 11, 13, 15, 17, 22, and 28. Rumen fluid for volatile fatty acid and lactic acid analysis was collected at 11 time points on each of d 2, 4, 6, 13, and 15. Yields of milk and milk protein and lactose were similar, but milk fat concentration tended to be higher in cows that received the placebo. Time spent eating and ruminating and dry matter intake were similar across treatments. Ruminal lactic acid concentrations were highly variable between animals, and no cases of clinical acidosis were observed. Both treatment groups had rumen pH <5.6 for more than 3h/d (a commonly used threshold to define subacute ruminal acidosis), but the length of time with rumen pH <5.6 was markedly reduced in the days immediately after dosing and fluctuated much less from day to day in cows that received M. elsdenii compared with those that received the placebo. Ruminal total volatile fatty acid concentrations were similar across treatments, but the acetate:propionate ratio tended to be smaller in cows that received M. elsdenii. Despite the lack of a measurable treatment effect on ruminal lactic acid concentration, supplementation of early lactation dairy cows with lactate-utilizing M. elsdenii altered the rumen fermentation patterns in favor of propionate, with potential benefits for energy balance and animal productivity.

Natural and improved natural pastures on the reproductive performance of first-calf beef cows

This work evaluated the reproductive performance of first-calf cows at three years of age, submitted or not to protein supplementation at yearling on natural pastures. After calving, cows were managed on natural or improved pastures. The feeding managements were the following: on natural pastures as yearlings and during pregnancy, post-calving period and breeding season; on natural pastures with protein supplement as yearlings and only natural pasture during pregnancy, post-calving and breeding season; on natural pastures as yearlings and during pregnancy and on improved natural pastures (Lolium multiflorum L., Trifolium repens cv. Yi and Lotus corniculatus cv. São Gabriel) during the post-calving period and breeding season; on natural pastures with protein supplement at yearling, on natural pastures during pregnancy, and on improved natural pasture during post-calving period and breeding season. Cows did not differ on body weight, but from calving to the beginning of breeding season, cows on improved natural pastures presented higher weight gain than those on natural pastures (0.203 vs. 0.109 kg/day). Cows in post-calving on natural pastures lost 1.0 point of body condition score during mating, determinant of the lowest pregnancy rate and later conception in relation to cows on improved natural pasture. Pregnant cows presented higher body weight (440 vs. 413 kg) and body condition score (4.14 vs. 3.66 points) than open cows at the end of the breeding season.

Pre- and post-calving forage systems and reproductive performance of primiparous cows

During pre and post calving periods, it was evaluated the influence of the following forage systems on reproductive performance of primiparous cows: natural pasture during pre and post-calving periods; natural pastures during pre-calving period and improved pastures during post-calving period; improved pastures during pre-calving and natural pasture during post-calving; improved pasture during pre- and post-calving periods. The lowest body weights and body condition scores were observed on cows kept on natural pastures pre-calving (384.3 kg and 3.31; 391.4 kg and 3.60), followed by those on improved pastures during pre-calving and on natural pasture during post-calving period (424.4 kg and 3.60), finally, cows on improved pasture during pre- and post-calving period (421.2 kg and 3.59). Cows on improved pastures pre and post-calving showed higher body weight and body condition score in the beginning of the breeding season (442.1 kg and 3.76), higher pregnancy rate (82.3%) and they conceived earlier. Natural system during pre-calving and improved on post-calving and that with improved pasture in pre-calving and natural in post-calving did not differ on weight at the beginning of breeding season (417.2 and 409.8 kg) and on pregnancy rate (65.8 and 62.8%), respectively. However, cows on natural pasture in pre-calving and on improved pasture in post-calving conceived earlier. Cows on natural pastures showed lower weight in the beginning of breeding season (391.2 kg), the lowest pregnancy rate (52.7%), and they conceived later. Cows maintained on improved pastures pre- and post-calving improved weight and body condition score at calving and beginning of the breeding season making high reproductive performance possible.

The Hsp72 response in peri-parturient dairy cows: relationships with metabolic and immunological parameters

The study was aimed at assessing whether the peri-parturient period is associated with changes of intracellular and plasma inducible heat shock proteins (Hsp) 72kDa molecular weight in dairy cows, and to establish possible relationships between Hsp72, metabolic, and immunological parameters subjected to changes around calving. The study was carried out on 35 healthy peri-parturient Holstein cows. Three, two, and one week before the expected calving, and 1, 2, 3, 4, and 5weeks after calving, body conditions score (BCS) was measured and blood samples were collected to separate plasma and peripheral blood mononuclear cells (PBMC). Concentrations of Hsp72 in PBMC and plasma increased sharply after calving. In the post-calving period, BCS and plasma glucose declined, whereas plasma nonesterified fatty acids (NEFA) and tumor necrosis factor-alpha increased. The proliferative responses of PBMC to lipopolysaccharide (LPS) declined progressively after calving. The percentage of PBMC expressing CD14 receptors and Toll-like receptors (TLR)-4 increased and decreased in the early postpartum period, respectively. Correlation analysis revealed significant positive relationships between Hsp72 and NEFA, and between PBMC proliferation in response to LPS and the percentage of PBMC expressing TLR-4. Conversely, significant negative relationships were found between LPS-triggered proliferation of PBMC and both intracellular and plasma Hsp72. Literature data and changes of metabolic and immunological parameters reported herein authorize a few interpretative hypotheses and encourage further studies aimed at assessing possible cause and effect relationships between changes of PBMC and circulating Hsp72, metabolic, and immune parameters in dairy cows.

The effect of time of day when dairy heifers are introduced to a group containing mature cows on welfare and performance

Introduction The integration of dairy heifers into the main herd during the post calving period can have negative effects on the heifer’s welfare and productivity (Gonzalez et al, 2003). This appears to be related to the fact that heifers attain low social status when entering the milking herd and therefore are subjected to increased levels of bullying and aggression (Wierenga, 1990; Knierim, 1999). The aim of this study was to assess if the time of day (i.e. after ‘AM’ or ‘PM’ milking) when freshly-calved heifers are introduced to a group containing mature cows influences the heifers’ welfare and performance.

Dynamic Responses of Calving Caribou to Oilfields in Northern Alaska

Past research has suggested that during the calving period, caribou (Rangifer tarandus) in Arctic Alaska generally avoid areas within 1 km of oilfield roads with traffic. However, avoidance is not absolute, and caribou may habituate to infrastructure (e.g., buildings, roads, well pads) and human activity. We conducted road-based surveys of caribou in oilfields on Alaska’s Arctic Coastal Plain during the late calving and post-calving periods of June in 2000–02. We recorded location, composition, and behavior of caribou groups located less than 1 km from active gravel roads and production pads. Caribou groups with calves were on average distributed farther from oilfield infrastructure than were groups without calves, but habituation to oilfield activities, indicated by decreased avoidance, occurred at similar rates for groups with and without calves. During the calving period, sighting rates were greater in areas of low human activity, and calf percentages tended to be greater at night when oilfield activity was reduced. Caribou groups were on average closer to infrastructure during the post-calving periods than during the calving periods in 2000 and 2001, but not in 2002. In 2002, when snow melted early, caribou groups were closer to infrastructure during the calving period than in 2000 and 2001, when snow melted later, emphasizing the importance of examining environmental variables when investigating the dynamic interactions of caribou and oilfields. Overall, caribou appeared to habituate to active oilfield infrastructure after the calving period in 2000, late in the calving period in 2001, and likely before our sampling period in 2002. The timing of annual rehabituation was positively correlated with timing of spring snowmelt. Land and wildlife managers can use information from this study to develop calving period-specific mitigation measures that are more effective and flexible.

Distribution and Movements of the Teshekpuk Caribou Herd 1990–2005: Prior to Oil and Gas Development

Four caribou (Rangifer tarandus grantii) herds calve on the North Slope of Alaska, three of which have been exposed to little or no resource development. We present 15 years of baseline data on the distribution and movements of 72 satellite-collared and 10 GPS-collared caribou from the Teshekpuk caribou herd (TCH) that have had little to no exposure to oil and gas activities. Fixed-kernel home range analyses of collared caribou revealed that calving grounds were concentrated (i.e., 50% kernel utilization distribution) along the northeastern, eastern, and southeastern shores of Teshekpuk Lake. During the postcalving period, 51% and 35% of caribou moved through two constricted zones to the east and west of Teshekpuk Lake, respectively, and accessed insect-relief habitat along the Beaufort Sea coast. During late summer and early fall, TCH caribou were concentrated to the southeast and southwest of Teshekpuk Lake. Although 65% of the Teshekpuk caribou wintered in two areas on the central coastal plain around the village of Atqasuk and south of Teshekpuk Lake, other TCH animals wintered in a great variety of places, including the Seward Peninsula, the eastern and southern Brooks Range, and the Arctic National Wildlife Refuge. We detected an apparent emigration rate of 6.9%. One male and five female TCH caribou joined the breeding populations of the Western Arctic and Central Arctic herds. TCH caribou traveled an average distance of 2348 ± 190 km annually. Movement rates were at a maximum in midsummer, lowest in winter, and intermediate during spring and fall migrations. Restrictions on oil and gas leasing and surface occupancy have been in place to protect calving, migratory corridors, and insect-relief habitat for the TCH, but these protections are likely to be removed. These data will provide a good baseline that can be used to compare predevelopment distribution and movement patterns of TCH caribou to distribution and movement patterns during and after petroleum development.

Manejo de novilhas prenhes aos 13/15 meses de idade em sistemas a pasto

O trabalho foi realizado para avaliar o desenvolvimento de 32 novilhas primíparas gestantes Aberdeen Angus e mestiças Angus recriadas e acasaladas dos 13 aos 15 meses de idade. O experimento teve início no diagnóstico de gestação pela técnica de ultra-sonografia, realizado 28 dias após o término do período reprodutivo. O peso vivo (PV) inicial médio foi de 288 kg e a condição corporal (CC) inicial média de 3,2 pontos. Nesta ocasião, as novilhas foram distribuídas uniformemente por grupo genético, peso e ordem de concepção em dois sistemas de pastejo. Os sistemas de pastejo foram: PMI - novilhas prenhes mantidas na fase inicial de gestação em pastagem de milheto (Pennisetum americanum, L.); PNA - novilhas prenhes mantidas na fase inicial de gestação em pastagem natural. O pastejo em milheto foi mantido por 67 dias. Ao fim dos tratamentos, as novilhas foram manejadas em grupo único: no pré-parto em pastagem natural, no pós-parto em pastagem de azevém (Lolium multiflorum, Lam) e no segundo período reprodutivo em pastagem natural. Na fase inicial da gestação, o ganho médio diário (GMD), de 0,899 kg, e o ganho de condição corporal (GCC), de 0,34 pontos das PMI, foram superiores ao GMD de 0,377 kg e à perda de -0,15 de CC das PNA. As novilhas PMI tiveram peso vivo pós-parto (PVP) e condição corporal pós-parto (CCP) de 301 kg e de 2,9 pontos, valores superiores aos das PNA, de 267 kg e 2,7 pontos, respectivamente. As taxas de parição, distocia, natalidade e desmame não diferiram entre os tratamentos alimentares. As novilhas PMI chegaram ao início do segundo período reprodutivo com peso (31 kg a mais) e condição corporal (0,30 ponto a mais) superiores. A taxa de prenhez e as estimativas de eficiência produtiva ao parto (EPVP) e ao desmame dos bezerros aos 100 dias de idade (EPVD) não foram alteradas pelo tratamento alimentar. A TP média foi de 77%, a EPVP média de 30,3 e a EPVD de 28,1 kg de bezerro desmamado/100 kg de vaca.

Influence of post-calving regrouping strategy on welfare and performance parameters in dairy heifers

Thirty-six Holstein Friesian heifers (dairy herd replacements) were assigned to one of three regrouping treatments during the post-calving period. In Treatment 1, heifers were introduced individually to an established group of cows and heifers within 24 h of calving (‘Single—day 1’). In Treatment 2, heifers were housed individually in a straw pen for 1 week after calving before being added individually to the group (‘Single—day 7’). In Treatment 3, two heifers were housed together in a straw pen for 1 week after calving before being added as a pair to the group (‘Pair—day 7’). The size of the resident group remained constant at 16 animals (10 mature cows and 6 first-lactation heifers). The behaviour of the heifers was assessed during their first 8 h and first month in the resident group, and milk yield parameters, body condition loss and live weight loss were assessed during the first month post-calving. Reproductive performance was assessed during the post-calving period, and hoof health parameters were measured 1 month prior to calving, and at 1 and 3 months post-calving. Heifers in the ‘Pair—day 7’ treatment appeared to associate closely during their first month in the group by spending more time than expected in the same pen area and in adjacent cubicles ( P < 0.001). During the first 8 h in the group, heifers in the ‘Pair—day 7’ treatment tended to lie down more (when more than half of the resident group was lying) than heifers in other treatments ( P < 0.06). However, during the first month in the group heifers in the ‘Pair—day 7’ treatment appeared more active than heifers in other treatments ( P < 0.05), and it is suggested that this reflected reduced fearfulness. Heifers in the ‘Pair—day 7’ treatment also tended to show greater milk protein yields and milk fat + protein yields during the first month post-calving than heifers in other treatments ( P < 0.1). Heifers in the ‘Pair—day 7’ treatment showed greater hoof lesion scores at 3 months post-calving than heifers in other treatments ( P < 0.01), and it is suggested that this reflects greater levels of behavioural activity during the first month post-calving. There were no significant differences in behavioural and performance parameters between heifers in the ‘Single—day 1’ and ‘Single—day 7’ treatments. Reproductive performance, and post-calving live weight and body condition losses were not affected by any of the treatments in this study.

Effect of a Transition Diet on Production Performance and Metabolism in Periparturient Dairy Cows

The objectives of this study were to characterize the change in blood metabolites over time, and to evaluate the effect of dietary energy concentration on ketone body accumulation in periparturient cows. Twenty-eight multiparous Holstein cows were listed in order of their anticipated due dates and assigned randomly to 1 of 2 groups: with or without a transition diet. The control group received a nonlactating cow diet [1.54 Mcal/kg of net energy for lactation (NEL), 10.9% crude protein (CP), 53.1% neutral detergent fiber (NDF)] from 28 d before expected parturition, and a lactation diet (1.77 Mcal of NEL/kg, 16.8% CP, 29.9% NDF) after parturition. The treatment group received a transition diet (1.71 Mcal of NEL/kg, 16.8% CP, 35.2% NDF) from 17 d before parturition to 14 d after calving and was fed the same diets as cows in the control group during the third week of lactation. Blood from the coccygeal vein was sampled 3 times per week from 21 d before expected parturition to 21 d postpartum for analysis of glucose, nonesterified fatty acids (NEFA), β-hydroxybutyrate, acetoacetate, acetone, and glycerol. There were no significant differences in dry matter intake, milk yield, milk components, body weight change, and body condition score change during the postcalving period. Plasma concentrations of different ketone bodies changed in parallel, stayed relatively constant precalving, peaked after parturition, and then decreased but remained high compared with concentrations late in gestation. Plasma concentrations of NEFA and glycerol changed in a pattern similar to those of the ketone bodies. Feeding a transition diet resulted in a greater area under the curve (AUC) for glucose in the last 17 d of gestation, but in no effect within the first 21 d in milk. Acetoacetate AUC was greater for treatment cows than for control cows across the first 21 d in milk. The AUC of NEFA and glycerol between d 15 and 21 postpartum were greater for treatment cows than for control cows. Feeding a transition diet both before and after parturition was associated with greater mobilization of adipose tissue and greater exposure to ketone bodies in early lactation compared with abruptly changing to a lactation diet after parturition.

Hemato-biochemical andclinico-epidemiological aspects of parturient hemoglobinuria in Nili-Ravi buffaloes

For this study, 60 buffaloes suffering from parturient hemoglobinuria (PHU) were randomly selected from field cases occurring in three districts of Punjab, Pakistan and simultaneously, 60 clinically healthy buffaloes of similar description from the same localities were included for case control study. Clinico-epidemiological data were collected. Blood/serum samples from all buffaloes were collected and analyzed. The most prominent clinical sign was passing of red to coffee colored urine. Milk production was reduced and respiration and pulse rates were significantly accelerated. Ruminal motility was significantly weak and reduced along with characteristic straining while defecating. The case fatality was 15%. A significantly high occurrence of PHU was observed in the winter season (41.8%). Maximum number of affected buffaloes (25.0%) was in 4th lactation. Twenty-seven (45.0%) buffaloes developed hemoglobinuria in the post calving period and majority (59.3%) of these were within 1-23 days of calving. Of the 33 (55.0%) PHU affected pregnant buffaloes, 18 (54.6%) were in their third trimester. The highest cases of PHU were observed in buffaloes producing 10 or more liters of milk/day (42.5%). Recurrence of PHU was observed in 18.3% buffaloes. Mean values of total erythrocyte counts, hemoglobin concentration and packed cell volume were lower (P<0.001), while erythrocyte sediment rate was higher (P<0.001) in PHU affected buffaloes as compared to the values in healthy buffaloes. Neutrophils were significantly higher, while lymphocytes and erythrocytic glucose-6-phosphate dehydrogenase (G6PD) were lower, in PHU affected buffaloes than in healthy buffaloes. Serum phosphorus, copper and selenium were significantly (P<0.001) lower, whereas potassium, iron and molybdenum (P<0.001) were higher in buffaloes suffering from PHU than healthy buffaloes.

Influence of macro and micro minerals in the peri-parturient period on fertility in dairy cattle

Infertility in dairy cattle is a complex, multi-factorial problem that cannot be evaluated in isolation of other diseases and disorders. Clearly there is a role for the prevention of problems in the peri-parturient period, in particular hypocalcaemia, mastitis, lameness and retained placenta (RP), that all have a negative impact on the subsequent fertility of the cow. Minerals, trace elements and vitamins play a vital role in the prevention of these disorders at this time. Macro minerals are involved in the acid base status of the dairy cow and influence calcium metabolism. The use of anionic salts in combination with adequate calcium and magnesium supplementation may help to improve dry matter intakes and reduce negative energy balance in the post-calving period as well as prevent hypocalcaemia. Vitamin E and zinc are effective in prevention of mastitis that occurs predominantly in the first weeks of lactation, through enhanced antioxidant function and keratinisation of the teat canal. Lameness in dairy cattle also occurs mainly in lactation though most of the original insults to the hoof can occur prior to calving. Zinc and biotin are implicated in improving keratinisation of the hoof and prevention of this disease. Organic forms of zinc are retained better than inorganic sources and may provide greater benefit in disease prevention. Retained placenta can be reduced by prevention of hypocalcaemia and also adequate selenium status of the dairy cow. Selenium yeast is known to have higher retention in tissues and may play an important role in ensuring sufficient selenium is available to the cow for reduction of disease.

Effect of Metaphylactic Intramammary Infusion of 200 mg Cephapirin Sodium per Quarter in Dairy Cattle at 2-3 Weeks Prepartum on Selected Postpartum Production Parameters

The objective of this study was to determine the effect of a metaphylactic prepartum intramammary infusion of 200 mg cephapirin sodium (Cefa-Lak®) per quarter in heifers and mature dairy cows. Treated and control animals from a large, well-managed herd were evaluated for selected production parameters during the immediate post calving period.

C umulative E ffects of H uman D evelopments on A rctic W ildlife

: Recent discoveries of diamondiferous kimberlite deposits in the Canadian central Arctic led to unprecedented levels of mineral exploration and development. The cumulative effects of such activities are an issue of concern for government regulatory agencies, regional and international conservation organizations, wildlife managers, and indigenous peoples. We investigated the impacts of human activities and associated infrastructure on the distribution of Arctic wildlife in 190,000 km2 of the Taiga Shield and Southern Arctic ecozones 400 km northeast of Yellowknife, Northwest Territories, Canada. We used covariates for vegetation, interspecific interactions, and human disturbance features to develop seasonal resource-selection models for barren-ground caribou (Rangifer tarandus groenlandicus), gray wolves (Canis lupus), grizzly bears (Ursus arctos), and wolverines (Gulo gulo). We used an information-theoretic approach to select 11 seasonal models for the 4 species. Nine models were good predictors of species occurrence and vegetation covariates were important components of all models. Mines and other major developments had the largest negative affect on species occurrence, followed by exploration activities, and outfitter camps. We did not, however, record strong avoidance responses by all species during all seasons to each disturbance type (i.e., major developments, mineral exploration sites, outfitter camps) and for some models carnivores selected for disturbance features (i.e., occurred closer to sites than comparison random locations). We used a geographic information system (GIS) to extrapolate each seasonal resource-selection model to the study area and quantified the reduction in habitat effectiveness as a function of modeled and hypothetical disturbance coefficients. Across all models, grizzly bears and wolves demonstrated the strongest negative response to disturbance and corresponding reduction in habitat effectiveness, followed by caribou and wolverines. The largest seasonal effect was recorded for caribou during the post-calving period, where model coefficients suggested a 37% reduction in the area of the highest quality habitats and an 84% increase in the area of the lowest quality habitats. This is the first study to demonstrate the cumulative effects of multiple sources of human disturbance for caribou, wolves, bears, and wolverines found across the Canadian central Arctic. Resource selection models and corresponding maps of important habitats can be used to guide and evaluate future development proposals and can serve as a component of a regional environmental assessment. However, inferences from large-scale modeling efforts should be carefully evaluated when making detailed prescriptive recommendations. Study design, sample size, reliability of GIS data, and accuracy of model predictions are important considerations when evaluating the strength and scale of inference of correlative resource selection studies such as this. We recommend that regional cumulative effects analyses serve as the coarsest framework for understanding the impacts of human developments on wide-ranging animals. Monitoring and research should be conducted at various behavioral scales leading to a body of knowledge that fully describes the range and strength of impacts resulting from cumulative effects.