Reserve heifers and adult female cows at different life stages have distinct dietary requirements, nutritional needs, and management practices. To ensure optimal productivity and health, large dairy farms and breeding operations must implement efficient feeding and management strategies. Whether it's a replacement heifer or an adult cow, grouping them based on their stage of development or lactation is essential for effective care and performance.
**Adult Cows**
Adult dairy cows are typically divided into five groups according to their lactation stages:
1. **Dry Period (60 days):** This phase begins when milking stops and ends at calving. It’s a crucial time for the cow’s post-calving recovery and udder health. Proper nutrition and rest during this period help prepare the cow for the next lactation cycle.
2. **Late Perinatal Period (15 days):** This stage covers the 15 days before and after calving. It’s a critical time for the cow’s overall health and the establishment of high milk production in the coming months.
3. **Early Lactation (105 days):** From day 16 to day 120 after calving, this is the peak milk production phase, accounting for about 45-50% of total milk yield during the entire lactation period.
4. **Mid-Lactation (90 days):** From day 121 to day 210 after calving, milk production gradually declines but remains significant, contributing around 30% of the total milk produced.
5. **Late Lactation (90 days):** This phase lasts from day 211 until the end of milking, usually around the 8th to 10th month post-calving. Milk production drops further, making up about 20-25% of the total lactation yield.
**Reserve Heifers**
Reserve heifers, or replacement females, are categorized based on their physiological development:
1. **Lactating Calves (0-3 months):** This is the most vulnerable stage for heifers, with the highest risk of illness and mortality. Early care and nutrition are vital to survival.
2. **Weaned Calves (3-6 months):** This period marks rapid growth and development. Providing adequate feed and monitoring health is key to ensuring they reach their full potential.
3. **Young Breeding Cattle (6-12 months):** At this stage, heifers reach sexual maturity. Puberty typically occurs between 10 and 12 months of age, making this a critical time for reproductive planning.
4. **Growing Breeding Cattle (12-18 months):** This is the maturation phase, where the heifer prepares for her first pregnancy. By 16-18 months, she is considered a mature heifer ready for breeding.
5. **Pre-Breeding Young Cows (18-24 months):** During this stage, the heifer becomes pregnant and undergoes important breast development. Proper nutrition and management are essential for future milk production.
6. **Late Pregnant Heifers (24-27 months):** This is the final stage before calving, where the heifer transitions from a reserve animal to an adult cow. It’s a crucial time for preparing her body for the upcoming lactation cycle.
By understanding and managing each group appropriately, dairy producers can improve the health, productivity, and longevity of their herd.
Starch-based Plastics
Thermoplastic starch is also called "non-structured starch", which can make the starch structure disordered and thermoplastic by certain methods. Starch molecules for polysaccharides molecular structure, containing a large number of hydroxyl, due to its intermolecular and intramolecular hydrogen bond action, so that its melting temperature is higher, and its decomposition temperature is lower than its melting temperature, so in the heat processing, starch molecules did not melt and first decomposed. The traditional mechanical processing method of plastic is mostly heat processing, so to make starch - based whole starch plastic needs to make natural starch thermoplastic. This thermoplasticity can be achieved by changing the crystalline structure inside starch molecules. Destroy intramolecular and intermolecular hydrogen bonds, disrupt the double helix crystal structure of starch molecules, which will reduce the melting temperature of starch and make it thermoplastic.
Starch-Based Plastics,Cellulose-Based Plastics,Protein-Based Plastics,Some Aliphatic Polyesters
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