The effect of mid-cycle insemination on subsequent conception rates of cattle

Abstract

Extract

Sir,—The proportion of return intervals after first insemination of less than 18 days' duration is between 16 and 20% in New Zealand dairy cattle (Macmillan, 1970 Macmillan, K. L. 1970. Return intervals to first insemination and conception rates to second insemination in New Zealand cattle. N.Z. Jl agric. Res., 43 in press [Google Scholar]) whereas the comparable figure in American herds is 3.5% (Moeller and VanDemark, 1951 Moeller, A. N. and Van Demark, N. L. 1951. The relationship of the interval between inseminations to bovine fertility. J. Anim. Sci., 10: 988–992. [Web of Science ®] , [Google Scholar]; Flerchinger and Erb, 1954 Flerchinger, F. H. and Erb, R. E. 1954. Influence of treatment and fertility level of semen on distribution and non-return decline of repeat service intervals. J. Dairy Sci., 37: 949–949. [Crossref], [Web of Science ®] , [Google Scholar]). Since the incidence of these short cycles tends to increase with increasing: herd size, these short return intervals after first insemination may be the result of errors made by the farmer identifying or diagnosing oestrous cows. Such errors will arise because (1) the farmer correctly submits a cow in the first instance but then unnecessarily resubmits the same cow because of incorrect identification or diagnosis; (2) the initial incorrect submission is followed by correct diagnosis and submission; or (3) errors in detection and diagnosis are made on consecutive occasions.     

Feasibility Study of a Fish By-Product Recovery Plant with a Processing Capacity of 1,000 kg/Day

ABSTRACT

This study evaluates the feasibility of producing hamburger, silage, and leather using fish by-products in a medium-sized recovery plant with total capacity of processing up to 1,000 kg/day of whole fish. The average volume of fish by-products generated daily was 673 kg. The investment necessary to introduce these three technologies was US$47,193.13 in 1 year. The average cost to produce 1 kg of hamburger, silage, and leather was 1.24, 0.17, and US$1.77, respectively. The return of the investment was 56.16%, and the net present value US$570,582.16. The investment pay back was realized in 3.88 years, with a benefit/cost relationship of 1.31. For all the studied scenarios, sale price variations most influenced the economical parameters analyzed.     

Effect of ultraviolet (UV) radiation on the abundance and respiration rates of probiotic bacteria

Effects of ultraviolet radiation (UV) on probiotic bacteria (Bacillus subtilis and B. licheniformis) were tested in two experiments, with the following treatments: (i) UV treatment – using fluorescent and UV‐lamps and (ii) Control – CTRL, using fluorescent lamps. Bacterial abundance and respiration were evaluated every 24 h for 3 days for Experiment 1, and at 0, 6 and 24 h for Experiment 2. In the Experiment 1, total UV dose was 4 336.41 mW cm^?2. UV treatment presented small respiration rates only on day 3, while in the CTRL oxygen consumption was always high. On all days, the abundance of the Bacilli exposed to UV was significantly smaller than that of the CTRL. The second experiment, with total UV dose of 1 445.47 mW cm^?2, presented oxygen consumption in the UV treatment only during the first 6 h. In the CTRL, oxygen consumption increased from the beginning due to the bigger abundance Bacilli cells. Small coccus‐shaped bacteria ocurred in the UV treatment of both experiments. It may be concluded that exposure to UV, normally used for water disinfection, can inactivate probiotic bacteria.     

Ammonia and nitrite toxicity to false clownfish <Emphasis Type="Italic">Amphiprion ocellaris</Emphasis>

False clownfish, Amphiprion ocellaris, is one of the most commercialized fish species in the world, highly produced to supply the aquarium market. The high stocking densities used to maximize fish production can increase ammonia and nitrite to toxic levels. In this study, A. ocellaris juveniles (1.20 ± 0.34 g) were exposed to six concentrations of ammonia ranged from 0.23 to 1.63 mg/L NH₃-N and eight concentrations of nitrite (26.3–202.2 mg/L NO₂ ^?-N). The LC₅₀- 24, LC₅₀-48, LC₅₀-72 and LC₅₀-96 h were estimated to be 1.06, 0.83, 0.75 and 0.75 mg/L for NH₃-N and 188.3, 151.01, 124.1 and 108.8 mg/L for NO₂ ^?-N. Analysis of gill lesions caused by sublethal concentrations of these nitrogenous compounds showed that both nitrogenous compounds induced tissue lesions such as hyperplasia of epithelium cells, hypertrophy of chloride cells and lamellar lifting to all concentrations tested. However, histopathological alterations were more conspicuous accordingly the increase of ammonia or nitrite in fish exposed to 0.57 mg/L NH₃-N or 100 mg/L NO₂ ^?-N. Based on our results, we recommend to avoid concentrations higher than 0.57 mg/L of NH₃-N and 25 mg/L of NO₂-N in water.     

Carcass characteristics and meat quality of lambs fed babassu cake (<Emphasis Type="Italic">Orbignya speciosa</Emphasis>) as a replacement for elephant grass silage

The study aimed to evaluate the effect of the partial replacement of elephant grass silage with babassu cake (Orbignya speciosa) on the carcass characteristics and meat quality of feedlot lambs. Forty-five castrated male Santa Ines sheep (19.08?±?0.41 kg) approximately 4 months old were distributed in a completely randomized design, with five treatments 0.0, 12.5, 25.0, 37.5 and 50 % (%DM) replacement of babassu cake with silage forming isoproteic diets formulated at a ratio of 40 % roughage to 60 % concentrate. All of the studied animals were slaughtered at the end of the experiment. The liver weights and yields increased with the inclusion of babassu cake. The weight of the shoulder increased from 2.31 to 2.61 kg, while the loin yield decreased from 7.38 to 6.64 % with the inclusion of babassu cake, both linearly. The body length, thoracic perimeter, rump perimeter and carcass compactness index showed high and positive correlations with the hot and cold carcass weights. The myofibrillar fragmentation index decreased linearly as a function of the inclusion level of babassu cake, but other quality variables were not affected. The replacement of up to 50 % of the elephant grass silage with babassu cake in the diet of lambs does not cause negative effects on carcass characteristics or meat quality.     

Evaluation of the Integrity of Horse Hoof Dermal and Epidermal Tissues Collected by Dorsal Transmural Access

The purpose of this study was to evaluate the integrity of dermal and epidermal tissues collected by dorsal transmural access. Eight healthy adult horses were subjected to two biopsies of the right hoof, with a 24-hour interval. To ensure hoof integrity, a radiographic evaluation with dorsopalmar and lateromedial positions was performed. The animals were sedated, and the pedal tissue was collected from two sites that were 2 cm distal to the coronary band. For each biopsy, the hoof wall was perforated using an aluminum oxide drill bit, 4.8 mm in diameter that was connected to a drilling machine, yielding a hole of approximately 9.0 mm. The perforation procedure was performed slowly in the stratum medium until 1 mm of it remained, which was determined by evaluating the movement in response to pressure applied with a Halstead forceps. Laminar deep incisions were performed with a number 11 scalpel blade until the distal phalanx was reached. The laminar tissue was then removed using a Frahm scaler. A cuboid laminar sample measuring approximately 5 mm at the base and 7 mm in height was obtained. The samples were suitable for analysis by histology and transmission electron microscopy showing that the ends of the secondary epidermal laminae were round, the basement membrane was intact between the secondary epidermal laminae and secondary dermal laminae, and the ultrastructural analysis of the cells showed their structural integrity.