The effect of Zindep on B-lymphocyte levels in pregnant cows]

In the present study the immunomodulation effects of the Zindep preparation, based on elementary zinc and zinc oxide, were followed on the humoral response of gravid cows in the 8th and 9th months, a week after parturition and in calves immediately after parturition and on day 15 of their life. An increased level of B-lymphocytes was observed on days 2, 5, 8, 15, 30 and 50 of the experiment. The highest average values were recorded in the experimental group on days 8 and 15 of the experiment. The mentioned values were statistically significant (T-test) at the level 0.05 and 0.01. The average values of B-lymphocytes in cows after parturition reached 22.3% in the cows of the experimental group and 20.5% in the control group. No pronounced differences in the number of B-lymphocytes in the calves of both followed groups were recorded. The statistical evaluation of the values obtained in the cows after parturition as well as in the calves was not carried out due to a small number of samplings.     

Hepatic lipidosis in pregnant cows on a dairy farm.

A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period. After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.     

The effects of long haul transport on pregnant, non-lactating dairy cows

AIMS: The transport of dairy cows from the North to the South Island of New Zealand has been common in recent years. The aims of this study were to determine the serum biochemical and bodyweight responses of cows to such a journey, and to investigate the effects of pre-transport hay feeding. METHODS: Pregnant, non-lactating Jersey cows from two herds were transported by road (1196 km) and ferry (5 hours) over a 3-4 day period. Cows in each herd were allocated to three 4-day pre-transport feeding treatments (grass only, grass + hay, 3 days of grass then 1 day of hay). Twelve experimental cows selected from each treatment group were weighed and blood sampled before transport, on arrival, and 24 and 48 hours after arrival. Additional blood samples were collected from experimental animals in one herd before and after one of the overnight rest stops during the journey. Sera were analysed for serum betahydroxybutyrate, total protein, calcium and magnesium concentrations and creatine kinase (CK) activity. RESULTS: Cow bodyweights declined by 6 9% during the journey and although they increased after arrival, they were still lower (p<0.001) than pre-transport values 48 hours after arrival. Serum magnesium fell (p<0.001) from pretransport concentrations of 0.95 mmol/l (Herd 1) and 0.83 mmol/l (Herd 2) to mean values of 0.50 mmol/l for both herds after transport. Total protein and CK concentrations increased during the first day of transport in Herd 2 cows, but then declined during the subsequent overnight rest stop. Pre-transport feeding treatments did not consistently affect cow bodyweight or blood biochemical responses to transport. CONCLUSIONS: Transported cows benefited from overnight rest, feeding and watering in terms of hydration and muscle status, but bodyweight and serum magnesium concentrations were significantly reduced by the overall journey, emphasising the requirement for suitable mineral supplementation and careful feeding and selection of pregnant cows before long-haul transport.     

The protective effect of zinc sulphate in experimental sporidesmin intoxication of lactating dairy cows

Zinc sulphate solution, administered concurrently with the mycotoxin sporidesmin, gave significant protection against the toxin. The protective effect was shown in maintained milk production and bodyweights, and in reduced liver damage as determined by serum enzyme (gamma-glutamyltransferase, ornithine carbamyltransferase) analysis and by subjective grading of the liver damage after slaughter. There was no overt facial eczema in either group but, in sporidesmin dosed cows not receiving zinc sulphate, there was a fall in milk yield and in bodyweight. Serum enzyme levels did not rise until more than a week after dosing at which time milk yields were showing partial recovery. Serum concentrations of the enzyme gamma-gluta-myltransferase (EC 23.2.2) were found to be correlated to the severity of the liver damage observed at post-mortem.     

The effect of free amino acid levels in the blood and milk of cows on protein levels in milk

In the cows of the whole group under study, a significant negative relation (r = = -0.4797) was found between the histidine level in arterial blood and protein content in milk; further, there was a significant positive relation (r = 0.4624) between alanine level in milk and protein content in milk, and a significant negative relation (r = -0.5028) for the level of threonine. The group of cows with a higher milk output showed a significant negative relation between methionine level in milk and protein content in milk (r = -0.7482) and a highly significant negative relation between threonine level and protein content in milk (r = -0.8410). The negative relations of some amino acids to the content of protein in milk suggest that there is a poor supply of these amino acids for the production of protein in milk.     

Influence of different copper and zinc supply on their concentrations in blood serum, liver and hair of dairy cows

In a feeding trial at the Institute of Animal Nutrition of the Federal Research Institute of Animal Health (FLI) over 12 weeks with 20 cows of the German Holstein Breed the influence of different copper and zinc contents in the ration on their concentration in blood serum, liver and hair was tested. All animals received a diet based on maize- and grass silage ad libitum. The animals were divided in two groups with 10 cows each; group A received a concentrate according to their milk yield with a copper and zinc content as recommended (GfE 2001), whereas group B was offered a concentrate with roughly the double amount of copper and zinc. At the beginning and at the end of the trial a sample of blood, pigmented hair and a liver bioptate was taken from all animals to evaluate the incorporation of copper and zinc in these tissues. In serum and pigmented hair the copper concentrations did not differ between the two groups [13.4 for Group A and 12.5 micromol/L for Group B in serum respectively 6.8 (Group A) and 7.4 mg/kg DM (Group B) in pigmented hair]. Only the copper concentration in the liver was influenced by the different feeding. The higher copper content for group B resulted in a significantly higher copper concentration in the liver (506 mg/kg DM compared to 383 mg/kg DM). The liver is the best indicator organ for a sufficient copper supply. An increase in the zinc content in the ration resulted neither in higher zinc concentrations in serum (15.1 in Group B in comparison to 13.4 micromol/L for Group A) nor in higher zinc concentrations in liver (140 for Group B and 112 mg/kg DM for Group A) and pigmented hair (130 in Group A and 123 mg/kg DM in Group B). There is a significant correlation between copper intake and copper concentration in the liver (r = 0.46), whereas the correlation between zinc intake and zinc concentration in the liver is only tendencially (r = 0.23). The three tested samples serum, liver and cow hair are not qualified to reflect exactly a sufficient zinc supply.     

The adenohypophyseal response and effect of GnRh (Dirigestran inj. Spofa) administration in cows in the postpartum period

Radioimmunological investigation (RIA) of the level of pituitary FSH in the peripheral blood of cows after parturition demonstrated that this level increased successively. The FSH value of 32.93 +/- 3.71 ng per 1 ml, recorded the fourth to sixth day post partum, increased to as much as 57.78 +/- 40.98 ng per 1 ml 40 days after parturition. The LH level changed only slightly over the same period (from 1.12 +/- 0.21 ng per ml to 1.72 +/- 1.15 ng per ml). The concentration of progesterone in the blood of the cows was about 0.40 ng per ml during the first 15 days after parturition, but from the 25th day post partum it trebled, on an average (1.53 +/- 1.19 - 1.59 +/- 1.25 ng per ml). The response of the adenohypophysis of the cows to the administration of 200 micrograms of synthetic gonadoreline (spec. Dirigestran inj. Spofa) increased with increasing length of time from parturition. FSH concentration increased less markedly during the first 28 days p.p. and this increase was not uniform in time (the average increase was 1.5 to three times); in the later period the highest increase 300-500% was recorded, as a rule, 120 minutes after GnRH administration. The situation was similar in the increase in LH concentration in peripheral blood, but after the 26th day post partum the average increase in LH accounted for 500 to 600%. The concentration of progesterone in peripheral blood increased by more than 300%, on an average, from the 25th day after parturition. This testifies to the first post partum ovulation and to the formation of a new yellow body in the majority of cows under study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in lipid levels in the blood of pregnant sows]

Variations of plasma volume (PV) and variations of triglyceride, cholesterol, total lipid, beta-lipoprotein and phospholipid concentrations in the blood plasma were investigated in trials with ten sows, crossbreds of the White Thoroughbred and Landrace breeds, at the age of 2-3 years, kept on a defined diet; the trials were performed before the sows became pregnant and during their pregnancy (days 1-40, 41-60, 61-80, 81-100 and 101-120). The PV in nonpregnant sows is 9.8 +/- 0.33 1. Following a decrease to the values of 7.8 +/- 0.33 l (p less than 0.01) in the first 40 days of pregnancy the plasma volume increases in the successive periods and it makes 15.4 +/- 0.19 l at the end of pregnancy (p less than 0.001). Total lipaemia decreases during pregnancy from 2.80 +/- 0.054 in nonpregnant sows to 2.49 +/- 0.245 g per 1 in sows at the end of pregnancy. Cholesterol concentrations in the blood plasma also decrease from 2.48 +/- 0.53 in nonpregnant ones to 1.88 +/- 0.173 mmol per 1 (p less than 0.001) in sows at the end of pregnancy, beta-lipoprotein concentrations from 3.95 +/- 1.134 in nonpregnant ones to 3.47 +/- 0.199 g per l in sows on days of pregnancy 81-100 (p less than 0.05), phospholipid concentrations in the first 60 days of pregnancy from 1.62 +/- 0.079 before insemination to 1.29 +/- 0.05 mmol per l in sows of 41-60 day pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of beta carotene supplementation on the beta carotene and vitamin A levels of blood plasma and some fertility indices of dairy cows

Seasonal variations in beta carotene intake and low levels of beta carotene and vitamin A in blood plasma were found in cows fed ration based mainly on maize silage. The supplementation of daily winter rations with 300 mg Rovimix-beta carotene per cow, beginning 14 days before parturition and 60 days after calving increased slighty the beta carotene and vitamin A concentrations of blood plasma and improved some fertility indices: the number of inseminations per cow was reduced and the percentage of conception rate was significantly higher. It may be assumed that beta carotene content in feeds and it's utilization rate generally reflected in beta carotene blood plasma level and in the improvement of fertility.     

The influence of dietary protein upon blood composition in dairy cows.

Diets of different protein content were fed to dairy cows in two experiments of seven months and 12 months duration. Significant differences in the mean concentrations of serum urea, albumin and copper and of blood haemoglobin and packed cell volume were observed between cows receiving the various diets. The greatest differences occurred when cows were in mid-lactation. It was concluded that concentrations of urea in the serum of the cows were reflecting dietary protein intake and that concentrations of albumin, haemoglobin and PCV during lactation were affected by long-term protein status. The possible significance of the results is discussed in relation to previous reports indicating interrelationships between protein and copper metabolism, and in relation to the recommended protein content of diets for cows.     

输精部位对奶牛超排效果的影响

对奶牛超排时输精部位进行了研究。结果发现,在其它实验条件相同的情况下,在子宫角部位输精的供体牛的超排效果好于在子宫体部位输精的供体牛,其可用胚数(7±6.353)极显著高于子宫体部位输精的(4.182±1.870)(P<0.01),且无精卵数和停滞卵数(0.222±0.183和0.222±0.183)都分别极显著低于子宫体部位输精的(1.091±0.848和0.909±0.468)(P<0.01)。这说明超排时在子宫角部位进行输精能够提高超排效果。     

Protective effect of zinc sulphate in a natural facial eczema outbreak in dairy cows

The administration of a 50% (w/v) zinc sulphate solution by drenching gun to lactating dairy cows (30 mg Zn/kg/d) during the spore ingestion phase of a mild natural facial eczema outbreak had a marked prophylactic effect as judged by serum gamma-glutamyl transferase values. Weight changes recorded over the period of the experiment indicated that the zinc doses may also have caused inappetance or marginal toxicity under the conditions of the experiment.     

Heat stress in dairy cows. Its effect on reproduction

The effects of heat stress are most pronounced in the lactating dairy cow. The effects manifest themselves in several physiologic mechanisms and include negative effects on the duration of estrus, embryonic development, uterine blood flow, hormonal relationships, fetal growth, and subsequent milk yield.     

The effect of ivermectin treatment of late pregnant dairy cows in south-west Victoria on subsequent milk production and reproductive performance

SUMMARY A total of 498 dairy cows in 5 predominantly pasture-fed herds were allocated to pairs. One cow in each pair was treated with a single dose of ivermectin during the dry period. Treated and untreated cows were managed as a single group throughout the trial. Most cows calved between 45 and 115 days after treatment. When data from all herds were pooled, treated cows produced an extra 74 L of milk over the first 100 days of the subsequent lactation (95% confidence interval 20 to 128). Means were greater among treated groups relative to untreated groups in all 5 herds. However, when analysed individually, differences were statistically significant (P < 0.05) in 1 herd only. Over the complete lactation, mean milk volume for treated cows was 86 L greater than for untreated cows (95% confidence interval of difference -57 to 229; P = 0.24). Untreated cows produced 2473 L and 5883 L for the first 100 days of lactation and for the complete lactation, respectively. Milk production responses to treatment did not vary significantly with parity, body condition score, previous production index, calving date category or with plasma pepsinogen concentration or faecal egg count at the time of treatment. Faecal egg counts and plasma pepsinogen concentrations were low at the start of the study. The interval from calving to conception was 4.8 days less in treated cows (95% confidence interval 1.2 to 8.2) relative to untreated cows when data from all 5 herds were pooled. Differences within individual herds were not statistically significant.