Improving the Reproductive Efficiency by Zoo-Technical Methods at a Dairy Farm

This trial was conducted on a Hungarian dairy farm between July 2001 and December 2004. The objective of this work was to improve the reproductive efficiency with relatively high milk production. At the beginning of this trial blood and fodder samples were taken for checking the metabolic status of the animals in order to determine their health condition. The nutritive value of the daily ration for all groups met with the requirements of the Hungarian National Standard and almost all serum metabolic parameters differed between the milking and pregnant animals. Early pregnancy detection (by ultrasound) and ovulation synchronizing methods were introduced to optimize reproductive performance. The oestrus cycle was also checked by ultrasound and open cows were treated by the appropriate method in order to inseminate them as soon as possible. Efficiency of artificial insemination (AI) followed by a single prostaglandin F2alpha (PGF2alpha) and Ovsynch treatment was similar (30.8% and 29%) and less effective than AI after natural heat detection (37.1%). Provsynch (Pre-synch followed by Ovsynch) was the most effective ovulation synchronization method (conception rate=42.6%; p<0.01). Although milk production increased between 2002 and 2004 by approximately 600 kg per cow, the calving period decreased by 20 days and the number of AIs per pregnancy was also improved (0.8 AI per conception). These findings are really beneficial economically because the decrease in the calving interval returns profit for the dairy farms; one open day costs euro2.5/cow. Economical analysis showed a high profit ratio from the reproductive 'investment' on this farm. Every invested euro yielded approximately euro10.     

Anthelmintic efficacy of febantel combined with praziquantel against Ancylostoma tubaeforme, Toxocara cati, and Taenia taeniaeformis in cats

Forty cats, each harboring 2 or 3 parasitic infections (Ancylostoma tubaeforme, Toxocara cati, and/or Taenia taeniaeformis), were used to titrate the anthelmintic efficacy of a paste containing 3.4% febantel and 0.34% praziquantel. The cats were allotted into 4 groups (10 cats/group). For 3 consecutive days, the cats were given febantel/praziquantel at 5/0.5 mg/kg/day, 10/1 mg/kg/day, 15/1.5 mg/kg/day, or a blank paste vehicle (control) at 0.29 g/kg of body weight. The recommended dosage of 10 mg of febantel and 1 mg of praziquantel/kg cleared greater than or equal to 98% of the 3 helminth species.     

Emerging technologies for identifying superior dairy cows in New Zealand

The performance of animals is determined by the interaction of their genes with environmental circumstances. Accordingly, animals exhibiting superior performance are not necessarily the animals with the best genes nor are they the best choice of parents. Statistical analyses of production records for repeated traits, e.g. lactation yields and reproductive performance, show that part of the variation in performance among animals in the same herd and year is due to genetic differences, and the remainder is due to so-called residual or environmental factors that are not passed on to offspring. These within-herd environmental factors can be partitioned into a component that affects performance throughout an animal's lifetime, and a part that is unique to each observation. The process of animal evaluation from pedigree and performance records partitions the superiority of each cow into these three components. Reliable assessment of the genetic merit of bulls has required progeny testing, and for cows has required observation of their own individual performance. Selection on the genetic or breeding value component has systematically improved animal performance over recent decades, but has been limited by the age at which assessments of genetic merit are available.

Emerging molecular technologies can read DNA sequences or measure RNA expression and have allowed the identification of a number of chromosome regions, and a few specific genes in those regions, that influence economic performance. This information allows better characterisation of the relationships between animals and more accurate predictions of genetic merit in bulls without progeny information and in cows that have yet to produce their own performance record. At some stage, enough genes responsible for variation in performance will be identified to allow faster genetic progress through selection of animals at young ages and therefore more rapid turnover of the generations. Mechanisms that modify gene expression have been identified and these may ultimately allow animals to be selected at an early age for lifetime productivity, accounting for processes that modify gene expression and lead to differences in performance that are not reflected by DNA sequence information. This review describes the status of these emerging technologies and their likely role in the improvement of dairy cattle.     

Controlled dosage titration of febantel paste in naturally parasitized cattle

A controlled anthelmintic trial was conducted to determine the efficacy of febantel paste (45.5%) at dosages of 2.5, 5.0, 7.5, and 10.0 mg/kg in calves harboring natural gastrointestinal nematode infections. Dosages of 5.0, 7.5 and 10.0 mg of febantel/kg of body weight were greater than 96% effective in removing adults of Haemonchus contortus, Ostertagia spp, Cooperia spp, and Oesophagostomum radiatum. The 2.5 mg/kg dosage was considered suboptimal because of low efficacy against Ostertagia and Cooperia spp. Efficacies against Trichostronglylus axei, Trichuris spp, Bunostomum phlebotomum, and Stronglyloides papillosus were difficult to determine because fewer numbers of these nematodes were recovered. Efficacies of febantel paste against immature bovine parasites ranged from 83.62% to 97.72%.     

Renal effects of Dirofilaria immitis in experimentally and naturally infected cats

Canine heartworm infection has been associated with glomerular disease and proteinuria. We hypothesized that proteinuria, likely due to glomerular damage, would also be found in cats experimentally and naturally infected with Dirofilaria immitis. Two populations of cats were evaluated, including 80 that were each experimentally infected with 60 infective heartworm larvae as part of a drug safety study, and 31 that were naturally infected with D. immitis. Each had a control population with which to be compared. In the experimentally infected group, we evaluated urine from 64 cats. Ten of these cats were shown to have microalbuminuria 8 months post infection. No cat refractory to infection with larvae and no cats from the control group demonstrated microalbuminuria. All 10 microalbuminuric cats were shown to have significant proteinuria, as measured by the urine protein:creatinine ratio. There was a subtle, but significant, association between worm burden and proteinuria, and although the presence of adult heartworms was required for the development of proteinuria, both microfilaremic and amicrofilaremic cats were affected. Neither the presence of circulating heartworm antibodies and antigen nor the presence of antigenuria predicted the development of proteinuria. Both heavily infected cats (5-25 adult heartworms) and cats with worm burdens compatible with natural infections (1-4 adult heartworms) developed proteinuria, and the relative numbers of cats so affected were similar between heavily and more lightly infected cats. Naturally infected cats, for which only dipstick protein determinations were available, were shown to have a significantly greater incidence of proteinuria (90% vs 35%) than did those in an age- and gender-matched control population. Additionally, the proteinuria in heartworm-infected cats was 3- to 5-fold greater in severity. We conclude that cats infected with mature adult heartworms are at risk for developing proteinuria and that this is recognized relatively soon after infection. While heavier infections may predispose cats to developing proteinuria, this complication is seen in naturally infected cats and experimental cats with worm burdens similar to those seen in natural infections (i.e., "clinically appropriate" worm burdens). The clinical relevance of heartworm-associated proteinuria is yet to be determined.