While spring-calving herds are mid-way through their milk production season, most autumn-calving herds are approaching the end of theirs.
Cows that calved last autumn are now in late lactation, and should be assessed to ensure that they are in the correct body condition score (BCS) of 3.0 at calving.
To assess the BCS of a cow, check the fat cover over the loin, plates and pin bones of the pelvis and tail areas using your hand.
Each person assesses cows differently and gives cows different scores; once you are consistent over your herd, this is not an issue.
Cows should have a BCS of 2.5-3.0 at the moment. Over-conditioned cows are defined as having a BCS of greater than 3.25. Management of these cows is just as crucial as the management of thin cows.
BCS on a five-point scale:
Score 1: Individual transverse processes are fairly sharp to the touch and there is no fat around the tail head. Hip bones, tail head and ribs are visually prominent;
Score 2: Transverse processes can be identified individually when touched, but feel rounded rather than sharp. There is some tissue cover around the tail head and over the hip bones. Individual ribs are no longer obvious;
Score 3: Transverse processes can only be felt with firm pressure. Areas either side of the tail head have a fat cover that is felt easily;
Score 4: Fat cover around the tail head is evident as slight ’rounds’, and is soft to touch. Transverse processes cannot be felt even with firm pressure. Folds of fat are developing over the ribs;
Score 5: Bone structure is no longer noticeable and the animal presents a ‘blocky’ appearance. Tail head and hip bones are almost completely buried in fat, and folds of fat are apparent over the ribs. Transverse processes are completely covered by fat, and the animal’s mobility is impaired.
If you have cows that are below the optimum score and are well past 200 days in milk, you need to increase their dry matter (DM) intake.
According to the Department of Agriculture, Environment and Rural Affairs (DAERA), you should consider feeding 1-3kg/day of a low protein/cereal based concentrate.
This is a practical option you can use to increase the overall feed and energy intake of these animals.
Another option is to milk these cows once a day (OAD) in the lead up to drying off. If you do choose to operate OAD milking on thin cows, it is important to continue feeding cows concentrates twice a day.
The simplest way to do this is to leave the cows in with the main herd, but clearly mark these cows so they can be easily identified.
Managing BCS during dry period
The continued management of BCS during the dry period is important for successful calving.
Autumn-calving cows with a BCS of 3.5 or more have a high incidence of post-partum disorders, including: fatty liver; milk fever; retained placenta; metritis; and ketosis.
These cows will lose excessive condition after calving, resulting in: poor expression of oestrus; decreased conception rates; and increased incidence of embryonic mortality.
However, having cows that calve-down too thin means they are unlikely to reach the target BCS of between 2.5-3.0 at the start of breeding.
This results in a high proportion of non-cycling cows at the beginning of breeding, which will have a negative impact on submission and conception rates.