Vet’s Voice: Reproductive efficiency | TSLN.com

Vet’s Voice: Reproductive efficiency

Dave Barz, DVM

What a strange spring: rain, cold, floods, and of course, wind! It’s hard to believe that the first day of summer is just around the corner. This is the official start to the breeding season for most cow-calf producers in the area. Granted, many producers breed some heifers early, but most of the cows are bred after mid-June. I realize with the high prices for calves that “any cow raising a calf makes money,” but we need to improve efficiency now to be ready should less profitable times return.

Reproductive efficiency is measured by the number of cows that conceive during the first heat cycle, or 21 days. Cows that breed within this time frame rear calves that are consistent in both size and age for future marketing. The workload for the producer at calving time is greatly reduced if 75-80 percent of the cowherd calves within the first 30 days of the season. Once this number is achieved, it is easier to maintain a high fertility level because these cows will tend to recover from calving and be ready to cycle in subsequent years.

There are several things producers should address if they want a concentrated calving season:

• Vaccinations. Make sure cows are properly vaccinated for health problems that exist in your area. Talk with your veterinarian or livestock extension specialist and devise a program which works well in your herd. Be sure to administer vaccinations well in advance of turnout to insure adequate immunity and to avoid interference with egg production.

• Nutrition. Cows must be in adequate body condition to cycle. This spring we are seeing many thin cows. These animals usually will not cycle until they reach a positive energy level or are gaining weight. This is tough to do when the cow is milking heavily. Middle-aged cows are best at handling the pressure of lower body condition scores (BCS). The youngest and oldest cows are more likely to respond poorly to nutritional problems. It is important to assess the age of your herd as well as BCS. Consult with your nutritionist and decide if some supplementation is needed to jump-start these animals into a positive energy status and stimulate estrus.

• Bull power. Make sure bulls are ready to service as many cows as possible. Most bulls have completed the prebreeding phase of semen evaluation and vaccination. Hopefully the bulls have been selected and sorted for each pasture and have been allowed to become accustomed to each other. This eliminates some of the fighting and injuries which occur as bulls establish dominance in the pasture. Watch closely for injuries and lameness, and remove any bull with problems.

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Late-calving cows are the source of many problems to the cow-calf producer. Sometimes they are disease carriers which allow the rest of the herd to become exposed constantly to disease organisms. Others may be reproductively inferior to the rest of the herd. Sometimes these animals are “hard keepers,” which may be a result of poor roughage conversion or merely poor consumption because they are not as aggressive as the rest of the cows in the herd. All of these problems predispose the female to producing a late calf.

It is important to sort females by both BCS and age. Remember the mature, middle aged cow is the easiest to rebreed. These are the foundation of the herd. The young cows are the future of the herd. Segregate them and try to induce them into early heats. Make sure mineral and nutrition are adequate. Several procedures have proven valuable for stimulating heats: inject GnRH; feed MGA; or CIDR usage.

The future of the cowherd depends on the success of the breeding program. Careful attention to detail and planning will insure positive results to the breeding program. Not only will it result in better calf groupings, but the labor required at calving will be decreased. By keeping calf health issues at a minimum, you will produce more, healthy and consistent calves.

What a strange spring: rain, cold, floods, and of course, wind! It’s hard to believe that the first day of summer is just around the corner. This is the official start to the breeding season for most cow-calf producers in the area. Granted, many producers breed some heifers early, but most of the cows are bred after mid-June. I realize with the high prices for calves that “any cow raising a calf makes money,” but we need to improve efficiency now to be ready should less profitable times return.

Reproductive efficiency is measured by the number of cows that conceive during the first heat cycle, or 21 days. Cows that breed within this time frame rear calves that are consistent in both size and age for future marketing. The workload for the producer at calving time is greatly reduced if 75-80 percent of the cowherd calves within the first 30 days of the season. Once this number is achieved, it is easier to maintain a high fertility level because these cows will tend to recover from calving and be ready to cycle in subsequent years.

There are several things producers should address if they want a concentrated calving season:

• Vaccinations. Make sure cows are properly vaccinated for health problems that exist in your area. Talk with your veterinarian or livestock extension specialist and devise a program which works well in your herd. Be sure to administer vaccinations well in advance of turnout to insure adequate immunity and to avoid interference with egg production.

• Nutrition. Cows must be in adequate body condition to cycle. This spring we are seeing many thin cows. These animals usually will not cycle until they reach a positive energy level or are gaining weight. This is tough to do when the cow is milking heavily. Middle-aged cows are best at handling the pressure of lower body condition scores (BCS). The youngest and oldest cows are more likely to respond poorly to nutritional problems. It is important to assess the age of your herd as well as BCS. Consult with your nutritionist and decide if some supplementation is needed to jump-start these animals into a positive energy status and stimulate estrus.

• Bull power. Make sure bulls are ready to service as many cows as possible. Most bulls have completed the prebreeding phase of semen evaluation and vaccination. Hopefully the bulls have been selected and sorted for each pasture and have been allowed to become accustomed to each other. This eliminates some of the fighting and injuries which occur as bulls establish dominance in the pasture. Watch closely for injuries and lameness, and remove any bull with problems.

Late-calving cows are the source of many problems to the cow-calf producer. Sometimes they are disease carriers which allow the rest of the herd to become exposed constantly to disease organisms. Others may be reproductively inferior to the rest of the herd. Sometimes these animals are “hard keepers,” which may be a result of poor roughage conversion or merely poor consumption because they are not as aggressive as the rest of the cows in the herd. All of these problems predispose the female to producing a late calf.

It is important to sort females by both BCS and age. Remember the mature, middle aged cow is the easiest to rebreed. These are the foundation of the herd. The young cows are the future of the herd. Segregate them and try to induce them into early heats. Make sure mineral and nutrition are adequate. Several procedures have proven valuable for stimulating heats: inject GnRH; feed MGA; or CIDR usage.

The future of the cowherd depends on the success of the breeding program. Careful attention to detail and planning will insure positive results to the breeding program. Not only will it result in better calf groupings, but the labor required at calving will be decreased. By keeping calf health issues at a minimum, you will produce more, healthy and consistent calves.

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