Saranika Talukder

Rumination and activity levels as predictors of calving for dairy cows.

The Australian dairy herd size has doubled over the last 20 years substantially increasing the time that farmers require for individual animal attention to monitor and intervene with events such as calving. Technology will help focus this limited labour resource on individual cows that require assistance. The objective of this experiment was to first determine the profiles of rumination duration and level of activity as determined by sensors between, and within, days around calving and second to use these data to predict the day of calving for pasture-based dairy cows. After 2 weeks from the expected calving date, 27 cows were fitted with SCR HR LD Tags, located in 40×90 m2 paddock and offered ad libitum oaten hay and 2 kg grain-based concentrate/cow per day until calving. Hourly activity and rumination data for each cow, as determined by the SCR tags, were fitted with linear mixed models and all parameters were estimated using restricted maximum likelihood. Rumination duration decreased by 33% over the day prior and the day of calving, with the decline in rumination duration starting the day prepartum. Activity levels were maintained prepartum but increased in the days postpartum. The day of calving was recorded and used to determine the gold standard positive (the day before calving) and negative (all other) dates. A threshold rumination level of 0.9 (decline in rumination duration of 10%) gave the optimal combination of 70% sensitivity and 70% specificity. This experiment shows the potential to use rumination duration to predict the day of calving and the opportunity to use sensor data to monitor animal health.

Assessment of oxidative stress biomarkers in exhaled breath condensate and blood of dairy heifer calves from birth to weaning.

The balance between oxidants and antioxidants may be impaired in neonatal calves but only limited information is available on physiological changes in oxidative biomarkers in healthy calves. The aim of this study was to measure biomarkers of oxidative stress (OS) in calves from birth to weaning. Eighteen, healthy, female Holstein-Friesian calves were used in the study. Blood and exhaled breath condensate (EBC) samples were taken on the day of birth (Week 0) and then at Weeks 6, 12 and 18. Reactive oxygen metabolites (ROMs) and biological antioxidant potential (BAP) were determined on fresh blood and the degree of OS was expressed as an oxidative stress index (OSI), where OSI = ROMs/BAP × 100. Plasma concentrations of antioxidant barrier (OXY), thiol antioxidant barrier (SH), advanced oxidation protein products (AOPP), albumin, and non-esterified fatty acids (NEFA) were also measured, as was hydrogen peroxide (H2O2) concentration in EBC. Plasma concentrations of ROMs were relatively stable during the trial; AOPP concentration progressively decreased reaching its lowest values on Week 18. Albumin, SH and OXY concentrations progressively increased from birth to weaning. Concentrations of NEFA in plasma and H2O2 in EBC were relatively stable but peaked in Week 18. The results indicate that antioxidative defence not only increases with time in the plasma of new-born calves but also that it is related to protein oxidation processes. Furthermore, the data support the use EBC H2O2 as a novel biomarker to assess respiratory OS in calves.

Plasma oxidative stress biomarkers and progesterone profiles in a dairy cow diagnosed with an ovarian follicular cyst

This study was conducted to examine the oxidative stress biomarkers in a cow diagnosed with a follicular cyst in her left ovary. Progesterone (P4) and plasma oxidative stress status was measured in 13 Holstein cows after synchronization of oestrus with controlled internal drug release (CIDR) and prostaglandinF2α (PGF2α) protocol. The presence and size of ovarian structures were monitored by transrectal ultrasound at 4 hourly intervals. Of the 13 cows, 12 were monitored until ovulation was detected and recorded, whereas one cow failed to ovulate and developed a follicular cyst. Oxidative stress biomarkers; reactive oxygen metabolites (ROMs), biological antioxidant potential (BAP), oxidative stress index (OSI), glutathione (GSH), ceruloplasmin and advanced oxidation protein products (AOPP) were measured in the cystic cow and compared to those of the 12 ovulated cows and are referred to as higher or lower if they are outside the mean ± standard error of mean of those of ovulated cows. The cystic cow had lower ROMs and OSI between 36 and 84 h after PGF2α injection and at 9 h, from 36 to 60 h after PGF2α injection respectively. On the other hand, antioxidant (BAP and GSH) was higher in the cystic cow compared to her ovulated herd mates. The observed imbalance between oxidant and antioxidant might have disrupted the physiological events for ovulation to occur, leading to cystic ovarian disease.

Changes in plasma oxidative stress biomarkers in dairy cows after oestrus synchronisation with controlled internal drug release (CIDR) and prostaglandinF2α (PGF2α)

This study was designed to evaluate the plasma profiles of oxidative stress biomarkers, progesterone and ovarian follicle diameter in ovulatory versus an-ovulatory cows. Twenty cows were synchronised using controlled internal drug release (CIDR) and prostaglandinF2a (PGF2a) protocol. Plasma samples were analysed for progesterone (P4), oxidative stress (OS) biomarkers; reactive oxygen metabolites (ROMs), biological antioxidant potential (BAP), oxidative stress index (OSI = ROMs/BAP · 100), advanced oxidation protein products, ceruloplasmin and glutathione (GSH). Plasma P4 concentration was greater in ovulated cows 24 hours (h) after PGF2a treatment but lower 48 h after PGF2a treatment compared with that of an-ovulated cows at those sampling sessions (P < 0.05). Ovulated cows were diagnosed with greater ovarian follicle diameter compared with that of their herd mates not diagnosed for ovulation. Significant interaction of time of PGF2a treatment and ovulation status (ovulatory versus an-ovulatory) with the plasma concentrations of OSI, BAP and GSH were observed. Ovulated cows had significantly lower BAP compared with that of an-ovulated cows (P < 0.05) 9 h, 48 h, 60 h and 128 h after PGF2a treatment. Plasma concentrations of GSH were lower (P < 0.05) in ovulated cows than that of an-ovulated cows 60 h and 96 h after PGF2a treatment. However, OSI was greater (P < 0.05) in ovulated cows than that of an-ovulated cows 9 h, 48 h, 60 h and 128 h after PGF2a treatment. Significant associations were observed between OS status and sampling time. Oxidative stress status may have important physiological role in facilitating the ovulation process in oestrus synchronised dairy cows.

Changes in milk oxidative stress biomarkers in lactating dairy cows with ovulatory and an-ovulatory oestrous cycles

This study was conducted to evaluate changes in milk profiles of oxidative stress (OS) biomarkers in dairy cows with ovulatory and an-ovulatory oestrous cycles. Thirty healthy, cycling Holstein cows averaging 60±17 days in milk, and producing 33±6kg of milk per day (the week before commencing the study) were enrolled in this study. Composite milk samples were collected thrice weekly and assayed for the following OS biomarkers: lipoperoxides (LPO), biological advanced potential, superoxide dismutase (SOD), advanced oxidation protein products (AOPP), ceruloplasmin, glutathione (GSH), β-carotene and glutathione peroxidase (GSH-Px). Milk samples were also tested for fat and protein composition and the fat:protein ratio (FPR) was categorized as low (≤1.31), medium (1.32-1.56) and high (>1.57) to evaluate their main effect and the interaction effect of FPR and the week of study on OS using linear mixed models with cow identification being a random factor. Cows with ovulatory oestrous cycles (n=20) presented significantly greater SOD levels than cows that did not ovulate ((n=10; P<0.05). On the other hand, LPO, GSH-Px and GSH concentrations were lower in ovulated cows compared to the an-ovulated cows (P<0.05). The highest level of LPO and AOPP were noted at prooestrus phase while β-carotene presented the lowest value at that phase of oestrous cycle. It could be postulated that the elevated level of milk SOD and the observed lower level of LPO, GSH-Px and GSH in ovulating cows may be an essential event preceding the ovulatory response.

Role of oxidant?antioxidant balance in reproduction of domestic animals

Reproductive process leads to dynamic changes in metabolism and energy consumption, which may be responsible for the excessive production of free radicals (oxidants) that are generated during the physiological process of oxygen consumption. As the ovary is a metabolically active organ, it produces oxidants. Growing follicles, granulose cells of Graffian follicles and ovulated follicles all produce both enzymatic and non-enzymatic antioxidants to preserve themselves from the oxidative damage of oxidants. Oxidants and antioxidants are involved in several reproductive functions such as the regulation of follicular fluid environment, folliculogenesis, steroidogenesis, corpus luteum function, and luteolysis. In this article, the currently available literature is reviewed in relation to the roles of oxidants and oxidative stress in both normal and abnormal reproductive physiological processes.

Rumination patterns, locomotion activity and milk yield for a dairy cow diagnosed with a left displaced abomasum

Left displaced abomasum (LDA) is an important metabolic disease in dairy cattle, with diagnosis based on signs such as anorexia, decreased milk production and clinical examination by simultaneous auscultation and percussion (van Winden et al. 2003). One possible method to identify potential health problems in dairy cows before they show clinical signs is to use an automated system that records the activity profiles of an individual cow (Edwards and Toze 2004). Dramatic changes in rumination patterns can be attributed to sudden changes in intake and ill health (Bar and Solomon 2010), so a decrease in daily rumination along with a decrease in daily activity may provide an early warning to detect LDA in dairy cows. Here we report changes in the levels of rumination, activity and milk yield associated with an LDA before clinical diagnosis and after surgical correction.