The productivity of sows is the basis for the production of commercial pigs. The quality of sows also directly affects the quality of commercial pigs. Genetically, the number of sows in the litter of the sow and the weaned weight of the litter are inherited by the mother and sows should be selected accordingly. Healthy sows and sows from large burrows should be kept as gilts if their growth rate and lean meat percentage are high, whereas sows from small dens should not be kept.
Sow selection criteria
1. Perfect body appearance. A healthy physique means that there are no defects or shortcomings. When selecting a gilt, physique health means that there are no defects or shortcomings that can interfere with normal reproductive performance. There are three aspects to pay special attention to: genitals, breasts, and bones. When choosing a gilt, you must meet the minimum requirements of these three areas.
2. Sound fertility. The gilt should reproduce normally, the external genitalia should develop normally, and the small female in the vulva shows that the birth canal stays in the pre-development state. This type of sow should not be preserved.
3. Normal breast function. The gilt should have a sufficient number of healthy nipples. The gilts should each have at least 6 pairs of suitable nipples and a complete nipple. When the gilts reach the puberty, the mammary gland tissue should become more pronounced. It is normal for the nipple to develop.
4. Robust bones. Swing gilts with foot and leg problems should not be kept because they interfere with normal mating, delivery, and breastfeeding.
Precautions when selecting sows
1. Selection of gilt varieties. The determination of sow breeds should be based on the selected hybrid system. Most of the sows used in large-scale commercial hog production use the large-long, two-way hybrid sows as females, and the dual sows are mainly purchased from specialized breeding farms. Since sows are eliminated each year, a certain number of gilts should be purchased from the breeding farm each year. For the small group of self-breeding and self-breeding pigs, gilts can be selected from the hybrid offspring every year by means of progressive hybridization, and the boars can be purchased from the breeding farm on a regular basis. This may reduce the risk of frequent introductions, although the advantage of the sow's hybrid superiority is not sufficient.
2. Select the age of the sow. As a sow to be used as a species, it should be selected from the time of birth. First, select from the large litter size litter, and if the litter size of piglets in the litter, such as hernia, cryptorchidism and other deformed pigs, are not selected. Pre-prepared piglets should be marked with ear numbers. When weaning, check the number of piglets in the piglets and select sows that have more than 12 nipples with evenly spaced nipples. When the weight is 90 kg, the selected sow is separated from the hog and the pigs are restricted to feed and increase the amount of trace elements and vitamins in the feed. Observe the primates' gestation period, record well, wear ear numbers, and start mating after two to three love periods.
The narrowband filter is subdivided from the bandpass filter, and its definition is the same as the bandpass filter, that is, this kind of filter allows the optical signal to pass through in a specific wavelength band, but deviates from the outside of this wavelength band. Optical signals on both sides are blocked, and the passband of the narrowband filter is relatively narrow, generally less than 5% of the central wavelength value.
The narrowband filter is subdivided from the bandpass filter, and its definition is the same as the bandpass filter, that is, this kind of filter allows the optical signal to pass through in a specific wavelength band, but deviates from the outside of this wavelength band. Optical signals on both sides are blocked, and the passband of the narrowband filter is relatively narrow, generally less than 5% of the central wavelength value.
Its main parameters are: center wavelength, half maximum width (bandwidth), peak transmittance, cut-off range, cut-off depth (OD value)
Type: Generally, it can be any wavelength within 350nm~2000nm, the transmittance is greater than 70%, the cut-off wavelength is from 200nm to 3500nm, and the cut-off depth is 1OD~6OD
Let the visible light completely filter out only the near-infrared 940nm light that needs to be used, so that the CCD or CMOS photosensitive chip can form a black and white image. Through the calculation method of the biometric system, the human eye, iris, and face are tested to identify different people. Features, play access control security, hotel, entertainment venue monitoring, factory or office attendance.
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