Treatment Of Dairy Cows Research Articles

Effect of calcium chloride gel treatment in dairy cows on incidence of periparturient diseases

Objective To determine effect of prophylactic treatment of dairy cattle with a calcium chloride gel on serum calcium concentration in the immediate postpartum period and incidence of parturient paresis, retained fetal membranes, and displacement of the abomasum. Design Randomized controlled trial. Animals 204 Holstein cows. Procedure Cows were paired according to parity, whether they had previously had parturient paresis, and expected calving date. Cows in the treatment group received doses of calcium chloride gel 12 hours before expected calving, at calving, and 12 and 24 hours after calving. Cows in the control group did not receive calcium chloride gel. Results Compared with concentration in the control cows, mean serum calcium concentration in cows treated with calcium chloride gel was significantly increased on postcalving days 1 and 2. The increase was significant only in cows that were third parity or greater. Calcium chloride gel treatment also resulted in significantly reduced incidence of parturient paresis, parturient hypocalcemia, and displaced abomasum. The incidence of parturient paresis was lower in cows that received the precalving dose of calcium chloride gel (0/39) than in cows that did not receive the precalving dose (6/63). Clinical Implications Results suggest that periparturient prophylactic treatment of dairy cattle with an oral calcium chloride gel may be beneficial and that treatment would be most effective for cows of third parity or greater. Administration of a precalving dose of calcium chloride gel is necessary to reduce the incidence of parturient paresis, but postcalving treatment alone has other beneficial effects. (J Am Vet Med Assoc 1996;209:958-961)

Effect of sequential treatment with prostaglandin F2 alpha and/or oxytocin on estrus and pregnancy rate of lactating dairy cows

A total of 335 lactating dairy cows was used to determine the effect of oxytocin or PGF2a given 8 h after treatment with a luteolytic dosage of PGF2a on the percentage of cows exhibiting estrus within 7 d after treatment, and the pregnancy rate to a single insemination at this time. On the initial day of treatment (Day 0), cows with a palpable corpus luteum on the ovary were treated with 25 mg, im of PGF2a. At 8 h later, the cows were divided into 3 groups. Cows in Group 1 (n = 112) were treated with oxytocin (0.33 IU/kg bwt im); cows in Group 2 (n = 112) were treated with 25 mg, im of PGF2a; and cows in Group 3 (n = 111) served as the untreated controls. Cows in all 3 groups were continuously observed for estrus visually or by way of an activated heatmount detector within 7 d after treatment, and were inseminated within 12 h of the observed estrus.Plasma progesterone (P4) concentration was determined using radioimmunoassay on Day 0 and Day 2. Of the cows with P4 greater than 1 ng/ml on Day 0, the percentage of cows observed in estrus within 7 d after treatment was 75, 89 and 72% for cows in Group 1, Group 2 and Group 3, respectively. When all cows were evaluated, the percentage of cows observed in estrus within 7 d after treatment was 60, 70 and 55% for cows in Group 1, Group 2 and Group 3, respectively. In both instances, the value for cows in Group 2 was significantly higher than that for either cows in Group 1 or Group 3. The pregnancy rate for cows inseminated within 7 d was similar for cows in all 3 groups. The results of this study demonstrated that treatment of dairy cows with 2 luteolytic dosages of PGF2a at an 8-h interval resulted in more cows being observed in estrus within 7 d than with 1 treatment with PGF2a, or with oxytocin given at an 8-h interval after a luteolytic dosage of PGF2a.

Relationships between administration of GnRH, body condition score and fertility in Holstein dairy cattle

The objective of this study was to determine the effect of GnRH treatment in dairy cows differing in body condition score. A total of 2437 primiparous and multiparous cows was allocated randomly to receive either GnRH (100 μg) or placebo at the post partum exam (25 to 35 d) and at the first breeding. Complete records were available from 1906 cows: Group 1 (n = 535) placebo and placebo; Group 2 (n = 489) GnRH and placebo; Group 3 (n = 438) placebo and GnRH; and Group 4 (n = 444) GnRH and GnRH. The change of body condition score during early lactation was determined on a 1 to 5 scale (1 = emaciated to 5 = obese). Cows with a high body condition score (≥3.0) at the first breeding had 8.8 fewer days to first service and 6.4 fewer days open but more services per conception (0.16) than cows with low body condition score (<3.0). Conception rate improved when GnRH was administered at the first breeding to cows with a body condition score of <3.0 at the first breeding regardless of parity. The administration of GnRH at the post partum exam decreased the conception rate in first lactation cows but was beneficial for cows in second and greater lactations. Thus the efficacy of GnRH may not be consistent in all parities and body condition groups.

Effect of Treatment of Dairy Cows with Slow-Release Bovine Somatotropin During the Periparturient Period on Minerals in Plasma and Milk and on Parathyroid Hormone-Related Protein in Milk

Slow-release bST was given to dairy cows as a single injection prior to calving to determine whether such treatment prevented parturient hypocalcemia or modified the concentrations of Ca and parathyroid hormone-related protein in milk during the periparturient period. Cows were treated about 1 wk prepartum, and serial blood and milk samples were taken from these and similar prepartum control cows over a 3-wk period. Plasma growth hormone concentrations in the bST-treated group reached a peak 2 d after administration and then declined linearly to control concentrations over a 14-d period. Plasma Ca was unaffected by bST treatment 1 d prior to parturition, on the day of parturition, and at 1 and 6 to 9 d postpartum. Plasma P was higher, and plasma Mg was lower, in the bST-treated group on the day of parturition and 1 d postpartum. Concentrations of Ca, P, Mg, and protein in milk were lower in bST-treated cows than in controls at parturition. Milk production of the bST-treated and control groups was similar when measured at d 6 to 9 postpartum. Concentrations of parathyroid hormone-related protein in milk were substantial at parturition and remained high thereafter, although at parturition the concentration in the milk of the bST-treated group was lower than that of the control group.

A review of bovine growth hormone

Unprecedented numbers of technical papers, abstracts, and short communications have been published in the past decade regarding the effects of exogenous bovine growth hormone on milk production, health, and reproductive efficiency of treated dairy cows. In well-managed dairy herds, exogenous growth hormone increases milk production without altering normal variability in milk composition. This has held true regardless of dairy breed tested, geographical location studied, or feeding management system used. Also consistent across studies is the rapidity of the galactopoietic effect of administered bovine growth hormone, which arises from altered partitioning and use of post-absorptive nutrients and increased synthetic capacity of the mammary gland. Growth hormone and its associated peptide, insulin-like growth factor-I, are now known to provide chronic lipolytic, diabetogenic, and gluconeogenic signals to target tissues culminating in increased mammary gland availability of glucose and nonesterified fatty acids. Together with yet ill-defined effects on mammary secretory tissue, this homeorhetic control of metabolism elicited by exogenous growth hormone is so efficient that treated cows are not more susceptible to metabolic disorders than untreated cows. However, some studies have reported an increased frequency of mastitis in groups of treated cows. This has been attributed mainly to increased milk volume in the mammary glands of treated cows and no convincing data are available that show decreased mammary gland immunity as a result of growth hormone treatments. On the contrary, an expanding body of evidence implicates growth hormone as a key neuroendocrine factor that is required for immunological competence. Trends of decreased reproductive efficiency in cows treated with growth hormone have also been reported, but available data imply that this is probably an indirect effect via prolonged negative energy balance in cows treated in early lactation rather than a direct negative effect on estrous cycling via altered reproductive hormone profiles. The objectives of the present review are to bring into focus and summarize pertinent biological discoveries regarding the treatment of dairy cows with recombinant bovine growth hormone, and to explore areas where additional growth hormone research is needed or warranted. Key words: Growth hormone, somatotropin, dairy cows, insulin-like growth factor-I

Resumption of Follicular Activity and Interval to Postpartum Ovulation After Exogenous Progestins

In Experiment 1, treatment of dairy cows with progesterone using an intravaginal device from d 5 to 15 postpartum failed to alter onset or duration of the first estrous cycle. Compared with controls in Experiment 2, concentrations of FSH increased, and those of LH decreased, in cows treated with either norgestomet or progesterone for 6 d. Relationships of various measures of LH, but not FSH, were all positive with increasing days postpartum, and those of FSH produced positive polynomial regressions as days to first ovulation decreased. No significant changes in follicular status occurred during or after progestin treatments; however, a consistent relationship was observed between increasing diameter of dominant follicles and serum concentrations of estradiol-17β in most cows. Appearance of the ovulatory dominant follicle generally was detected 4 to 5 d before ovulation regardless of treatment and was first detected more frequently during treatment with progestins when concentrations of FSH were increased compared with controls. Concentrations of progesterone were higher on d 7 to 10 following removal of progestin treatments. Appearance of the first dominant follicle was detected during periods of increased average minimum concentrations of FSH, increased variation in LH secretion, and was related to subsequent duration of the first estrous cycle.

Effect of recombinant bovine somatotropin (rBST) on follicular IGF-I contents and the ovarian response following superovulatory treatment in dairy cows: A preliminary study

Somatotropin and FSH act synergystically on insulin-like growth factor-I (IGF-I) synthesis in ovarian follicles; IGF-I regulates several granulosa cell specific functions and may thereby be beneficial in bovine superovulation. In a series of 3 experiments we investigated the effects of recombinant bovine somatotropin (rBST) on several parameters of the superovulatory response in dairy cows. A total of 81 Holstein Friesian crossbred dairy cows received either 640 mg rBST or the vehicle (controls) on Day 4 or 13 of the superovulation schedule. Superovulation was induced with 2500 IU PMSG on Day 9. The cows were artificially inseminated on Day 13. In Experiment 1, on Days 4, 8, 11, 13 and 17 4 to 5 animals each were slaughtered to obtain follicular fluid, endometrium and plasma. The rBST application increased IGF-I contents in plasma and follicular fluid on Days 8, 11 and 13 (P < 0.05) in the treated cows when compared with that of the controls. Plasma and follicular IGF-I contents were correlated closely (rBST: r = 0.90, n = 10; control: r = 0.94, n = 9). The number of antral follicles increased following rBST treatment, and on the day of artificial insemination (AI) twice as many follicles > 4 mm were counted in the rBST treated animals than in the control group. In Experiment 2, the flushing of 38 donors on Day 7 after AI resulted in more transferable embryos in the rBST group than in the control group (4.2 ± 1.0 vs 2.5 ± 0.7; P < 0.05). In contrast, in Experiment 3 involving 21 animals when rBST was administered at the time of AI the superovulation response was not altered. It is concluded that rBST increases follicular and plasma IGF-I contents and thereby has profound effects on follicular and early embryonic development.

Estrus and pregnancy rate of dairy cows given one or two doses of prostaglandin F2 alpha 8 or 24 hours apart

A total of 329 cows was used in 2 experiments to study the effect of PGF2a given 8 or 24 h apart on the number of cows observed in estrus within 7 d and the pregnancy rate to a single insemination at this time. In Experiment 1, 233 cows were divided into 2 groups. Cows in Group 1 (n = 117) were treated twice with 25 mg, im of PGF2a (0 and 8 h) while cows in Group 2 (n = 116) were treated only once (0 h). In Experiment 2, 96 cows were divided into 2 groups. Cows in Group 1 (n = 49) were treated twice with 25 mg, im of PGF2a (0 and 24 h) while cows in Group 2 (n = 47) were treated only once (0 h). In Experiment 1, blood samples were obtained from cows in both groups on Days 0 and 2. However, in Experiment 2, blood samples were obtained from cows in both groups only on Day 0. Plasma progesterone concentration was determined using radioimmunoassay. Cows in both experiments were observed for estrus within 7 d of treatment and were inseminated within 12 h of the observed estrus. In Experiment 1, more cows in Group 1 were observed in estrus within 7 d than in Group 2 (P <0.03). In Experiment 2, there was no significant difference in the number of cows in both groups that were observed in estrus within 7 d. However, the interval from treatment to the first observed estrus for cows not observed in estrus within 7 d was significantly longer in cows treated at 0 and 24 h compared with the cows treated once at 0 h. In both experiments, the pregnancy rate for cows inseminated within 7 d was similar for cows in all groups. From the results of this study, it is concluded that treatment of dairy cows with 2 luteolytic dosages of PGF2a at an 8-h interval resulted in more cows being observed in estrus than at a 24-h interval.

Skin inflammation following triclabendazole treatment of dairy cows

Skin inflammation following triclabendazole treatment of dairy cows

Effects of recombinant bovine somatotropin (rbST) on productive and physiological parameters related to dairy cow welfare

Two trials have been carried out to evaluate welfare implications or rbST treatment in dairy cows. 1st trial: effects of rbST and F/C ratio on milk production traits, reproductive, metabolic and endocrine parameters were examined. Forty Italian Holstein Friesians (70 d post-partum) were divided into 4 groups: low concentrate (LC); high concentrate (HC); LC+rbST; HC=rbST. LC and HC groups were fed 0.35 and 0.50 kg concentrate/kg of milk yield >18kg. rbST (640 mg/cow) was injected at 28 d intervals for 112 d. 2nd trial: 4 dairy cows (191 d post-partum), each fitted with rumen cannula, were used in a crossover design to examine influence of rbST (640 mg/28 d) on rumen parameters. There was an average increase of 19% in 4% FCM for rbST versus control cows (24.6 vs. 21.0; 18.33 vs. 15.15 kg/d). Milk composition was unaffected except for a decrease (P<0.01) in milk protein percentage of LC+rbST group (2.87% vs. 2.94%). Days open were unaffected by rbST. Seven days post-injection, rbST significantly increased plasma GH, glucose, NEFA, triglyceride, phospholipid, insulin, somatostatin, lowered plasma urea and did not affect plasma total protein, albumin and total cholesterol. Somatotropin did not influence ruminal pH (6.08 vs. 6.10), concentrations of ruminal ammonia (8.28 mg/100 ml vs. 10.48 mg/100 ml), trotal ruminal VFA (111.73 mmol/1 vs. 114.09 mmol/1) and their molar proportion and liquid passage rate (14%/h).

The effect of treatment with a gonadotrophin releasing hormone on the fertility of dairy cows

Work in New Zealand has suggested that treatment of dairy cows with buserelin an analogue of GnRH between days 11 and 13 after insemination can increase pregnancy rate by reducing embryo loss (MacMillan, Taufa and Day, 1986). This effect is probably mediated via a luteoprotective mechanism (MacMillan, Thatcher &amp; Drost 1989; Thatcher, MacMillan, Hansen &amp; Drost, 1989). The present study was carried out to attempt to confirm this effect of buserelin under UK conditions.A total of 660 Holstein/Friesian cows on 10 commercial dairy farms were used. The cows were paired according to date, of previous calving and allocated at random to control or treated group on the day of service. Only cows in the parity range 1-5 with no obvious reproductive disorders were used. Bulls and inseminators were used on the same number of cows in each group. Milk samples were taken on the day of service for progesterone assay. Cows not in oestrus were removed from the study. Cows in treated groups were given an intramuscular injection of 10 ug buserelin [2.5 ml Receptal, Hoechst] 12 days after first insemination. Cows not observed to return to oestrus before Day 24 were re-sampled for progesterone assay. Pregnancy was confirned by palpation or ultrasonic scanning at six weeks.

Treatment of Dairy Cows with Recombinant Bovine Somatotropin: Genetic and Phenotypic Aspects

Thirty-four multiparous and primiparous Holstein cows were utilized to examine the association between the response to long-term administration of recombinant bovine somatotropin and the cow's phenotypic and genetic production potential. Cows representing a range of phenotypic and genetic production potentials were assigned to one of four treatment groups: 0, 12.5, 25.0, or 50.0mg recombinant bovine somatotropin daily. They were injected daily for 266 d beginning on d 24 to 35 postpartum. Pretreatment milk and fat yields were used to predict daily yields over the lactation and allowed treatment groups to serve as their own controls. Actual minus predicted yield estimated the response to treatment for milk, fat, and FCM for each cow. Milk composition (fat, protein, and lactose percentage) was not significantly affected by treatment. Response in yield for milk, fat, and FCM was significant during the treatment period (266 d). Milk yield increased by 18.5, 19.9, and 21.4%; fat yield increased by 13.4, 20.3, and 18.1%; and FCM increased by 16.3%, 19.7%, and 21.1% after receipt of 12.5, 25.0 and 50.0mg recombinant bovine somatotropin, respectively. Differences in response were not significant. The dramatic effect recombinant bovine somatotropin has on production requires that alternative approaches be adopted in the future for accurate genetic evaluation of sires and dams if somatotropin is discriminately used in the national herd.

Somatotropin Treatment of Dairy Cows and its Effects on Gastrointestinal Motility

Somatotropin Treatment of Dairy Cows and its Effects on Gastrointestinal Motility

EFFECT OF TWO-MONTH TREATMENT WITH GROWTH HORMONE-RELEASING FACTOR ON GROWTH HORMONE RELEASE IN DAIRY COWS

Two experiments were conducted to examine the effect of a human growth hormone-releasing factor fragment (hGRF(1–29)NH2) on growth hormone (GH) secretion in lactating dairy cows. An initial study was conducted on 12 lactating dairy cows to determine the dose effect (5, 10 and 20 μg kg−1) of a subcutaneous (s.c.) injection of hGRF(1–29)NH2 on GH secretion. The three doses induced similar GH response, with peaks and areas under the curve (AUC) of 38.5, 41.2 and 38.0 ng mL−1, and 3496, 4112 and 4079 ng mL−1 min at 5, 10 and 20 μg kg−1, respectively. In a second study, the GH response after daily s.c. injections of saline (n = 8) or 10 μg kg−1 of hGRF(1–29)NH2 (n = 9) for 57 d was evaluated in dairy cows averaging 252 d in lactation. Blood samples were collected on d 1, 15, 29, 43 and 57 of treatment. On the last day of treatment, the GRF-induced GH peak was higher than on the first day, 46.8 vs. 25.2 ng mL−1, while the AUC was not different, 4010 vs. 2684 ng mL−1 min. Finally, to determine if the pituitary's ability to release GH was modified after 57 d of GRF treatment, the 17 cows were challenged with an intravenous injection of hGRF(1–29)NH2 (1 μg kg−1). Control cows had a lower peak (21.8 vs. 32.2 ng mL−1) but a similar AUC (2190 vs. 2579 ng mL−1 min) than GRF-treated cows. Hence, in lactating dairy cows, (1) s.c. administration of hGRF(1–29)NH2 induced a similar GH release with doses ranging from 5 to 20 μg kg−1 and (2) the GRF-induced GH peak was higher after 57 d of GRF treatment while the AUC was not different. Therefore, 2-mo GRF treatment of dairy cows during their two last month of lactation does not result in a decreased GH response to GRF. Key words: Growth hormone-releasing factor, growth hormone, cows (dairy)

Fatty Liver in Dairy Cows

An increase in liver fat concentration during the peripartum period is extremely common in dairy cows and, to some degree, is probably normal. When severe, it is associated with clinical problems including increased morbidity and mortality and reduced breeding efficiency. Fatty liver develops when serum NEFA concentrations rise and hepatic uptake of NEFA exceeds the liver's ability to synthesize and secrete lipoproteins. In most cases, hepatic lipid accumulation appears to commence prepartum, in association with rising serum NEFA concentrations and declining serum lipoprotein concentrations. Commonly used clinicopathologic tests of liver function do not yield clearly abnormal results except in animals with extremely high concentrations of liver fat. Clinically useful estimates of hepatic lipid concentration can be obtained in the field by determining the buoyancy of needle biopsy samples in liquids of various specific gravities. Clinically ill animals with liver fat concentrations of greater than 35 per cent by weight have a poor prognosis, and those that do survive will have a protracted convalescence. Treatment of dairy cows with clinical fatty liver should be aimed at reducing further adipose lipid mobilization and promoting hepatic lipoprotein synthesis; however, protocols for therapy have not as yet been evaluated critically. Prevention of fatty liver is more rewarding than treatment. Dry cows should be maintained in a moderately fat condition and fed high-quality, palatable feeds in amounts necessary to met or slightly exceed their energy requirements. Free-choice feeding of high-energy feeds should be avoided in late lactation and during the nonlactating period.

Calving rate following fixed time insemination after a 12-day progesterone treatment in dairy cows, beef cows and heifers

Farm trials were carried out to determine if cows and heifers could be inseminated on a fixed time basis following a 12-day treatment with progesterone coils and an injection of 5 mg oestradiol benzoate and 200 mg progesterone at the start of treatment. The retention rate of the coils was significantly higher (P less than 0.05) when a 5.5 cm diameter was used compared with a diameter of 7.0 cm. Calving rate was similar in treated cows bred at a detected oestrus, at 56 + 74 hours after treatment or at 56 hours after treatment and injection of 100 microgram gonadotrophin releasing hormone 20 hours previously and in control cows bred at oestrus. Fertility to the first repeat oestrus was also similar in treated and control cows. Significantly (P less than 0.05) more synchronised cows calved following fixed time AI compared with the calving rate in control cows inseminated for a 24-day experimental period. In beef suckler cows, calved at least 50 days, and dairy heifers weighing over 280 kg, calving rate was similar in treated animals bred at 56 and 74 hours after treatment compared to calving rate in control animals bred at oestrus.

Retained foetal membranes in dairy herds in the Huntly district.

Abstract Extract During the period from April 1, 1964 to February 28, 1966, veterinary surgeons of the Huntly District Veterinary Club conducted an investigation into the incidence, the cause, subsequent fertility and treatment of dairy cows with retained foetal membranes.